.... ========================================================================= From: Nicholas McKinney Subject: [JN] Re: Date: Thu, 15 Apr 1999 12:50:23 -0400 Source: Sound Digest Archive v02.n125 At 04:07 PM 4/15/99 +0100, John Hancock wrote: > > > >Nicholas McKinney wrote: > >>John, more woofer speed is higher frequency, don't you mean more >amplitude? > >My definition of speed is velocity: the first derivative of position. Is >there another definition?--no incredulity intended, I suspect that there >might be a subjective hi-fi use of the word speed that I am unfamiliar >with. You can either change the speed of the movement (faster increases frequency, smaller period, same amplitude) or change the amplitude (changes SPL, same period, same frequency) The position of the woofer with the increased amplitude is increased from fore to aft, is this what you are talking about? >I don't question that at all for DC motor systems that convert current into >force. I'm talking about a positional system, though, where all of this is >irrelevent. Hmmm, I would imagine that unless you can make a pure monopole system, you will still have the issue of the rear wave that is 180 degree out of phase from the front wave. If these 2 waveforms are allowed to meet without change to one, the net effect is a cancelation of acoustic power, even though the electrical input was constant. Basically, you need to either stick the driver in a box to "seal" off the rear wave, or use the listening room as the box (woofer in the wall leading to the outdoors is an extreme example) Both of these can be modeling using TS parameters. Nick ========================================================================= From: Rich Barrett Subject: Re: [JN] Date: Sun, 15 Aug 1999 21:51:26 -0400 Source: Sound Digest Archive v02.n247 Help, I mentioned this list to a gentleman today and he was very interested in getting on, but I can't seem to find a link or the correct address to get him started. Can anyone help me to help him? TIA Rich Barrett rdbear@earthlink.net ========================================================================= From: Thomas Danley Subject: [JN] Re: Date: Thu, 09 Dec 1999 14:20:50 -0500 Source: Sound Digest Archive v02.n359 John Hancock wrote: > Aaron wrote: > > >I wanted to reread the discussion we had a couple of months ago regarding > >a positional subwoofer system driven by a stepper motor and controller. > >I've tried to find it in my archives, etc. but haven't been able to. Did > >anyone save this or does anyone know which digests they were? > > Aaron, > > I think you are refering to my hairbrained scheme, which I gave up on after > Tom Danley pointed out that I had done my math wrong. At the time, I was > thinking of using a stepper motor that had something like 16 bit resolution > per turn and about a 3000 rpm rating (I had erroneously done the math using > 3000 rotations per second, argghh). That's not enough resolution to get > very much bandwidth. However, since then I received a catalog from Pacific > Scientific and they have a brushless servo motor/feedback system that can > attain 24 bit resolution per turn and 6000 rpm. This makes the scheme > possible, but also a lot more expensive. The advantage of the steppers is > they are cheap. Let me know if you are crazy enough to pursue this, > > John Crazy idea? no no and I hope I didn't quash your sense of curiosity. Like they say (or at least they should) "Many of the biggest discoveries were made by people that didn't know what they had done was impossible". This certainly was true for me making the first servodrive, in fact if you asked anyone in audio at the time "can a rotary motor accurately follow a musical signal?" the answer was certainly no, its unimaginable.. You might consider using an "open loop" low inertia DC servomotor as well, they can be driven with a normal audio signal and if the DCR is ok, then are driven directly from a normal audio amplifier. They have no "steps" (analogue so to speak) and above very low power are a vastly more linear motor for a speaker than most voice coils (and much lower inductance) and the Xmax is only limited by the cone suspension. In terms of a "normal" speaker, a modest size servomotor can be the equal of a very large VC motor. For example a PacSci 4vm62 as we use them has a BL of 27 and Rdc of 2 ohms. For an 8 ohm nominal speaker (Rdc = 6 ohms), this same motor strength would require a BL of 46.7 a figure well beyond any single VC speaker motor I know of. More importantly, suitable motors are frequently available as new surplus for under $100.00 and Nick Mckinney has suitable passives for sale for the "Shiva" and other contraesque designs. While the design is patented, this only prevents one from making and selling them, the individual is always able to build any patented technology for there own use. Build, enjoy, for me, back to working on polar plots. Tom Danley ServoDrive inc / Sound Physics Labs www.servodrive.com ========================================================================= From: "John Hancock" Subject: [JN] Re: Date: Fri, 10 Dec 1999 11:16:07 +0100 Source: Sound Digest Archive v02.n359 Tom Danley wrote: >Crazy idea? no no and I hope I didn't quash your sense of curiosity. Don't worry, I don't discourage that easily. It is just simply not possible given the current state of stepper motor technology. When I was looking at this, the best stepper motor I found had a resolution of 25,000 per turn--approximately 16 bits per 2 revolutions--and a 3,000 rpm rating. That means the maximum frequency at which one could obtain 16 bit resolution with this system is: 3,000 rpm /60 seconds per minute / 2 revolutions / 2pi = 4 Hz Since, in a sealed-box system, for a given output level, excursion is four times smaller for each octave increase in frequency, resolution also falls 2 bits per octave. That means this system would provide only 8 bit resolution at 64 Hz. Now, since human hearing is somewhat poor at these frequencies, 8 bit resolution may not be that bad, but you still need 4 or 5 bits for volume control too. It seems that stepper motor technology is progressing pretty quickly, but it is not "there" yet. Now do the math at 24 bits resolution at 6000 rpm. The maximum frequency that this system can provide 24 bit resolution is: 6,000 rpm / 60 seconds per minute / 2 pi = 16Hz. That means 20 bit resolution at 64 Hz, 18 bit resolution at 128Hz--plenty even losing a few bits for volume control. This would be really simple to implement too--Pacific Scientific already offers a module that converts analog voltage into step-direction commands. The only thing you would have to worry about is some DC drift getting into the system--this system literally has extension to 0 Hz. Perhaps some kind of very-low-frequency filter could be programmed into the voltage-to-step-direction converter. Cost is the other issue of course. I haven't priced the hardware for this, but I'm assuming that it ain't cheap. >You might consider using an "open loop" low inertia DC servomotor as well, they >can be driven with a normal audio signal and if the DCR is ok, then are driven >directly from a normal audio amplifier. Actually that is what I'm working on now. I bought a few Pac Sci motors from C&H Sales after the discussion on the list. I've managed to find a source for Aramid pulley belts right here in Switzerland. I'm planning on ordering some driver frames, surrounds and spiders from Nick McKinney. I'll build the diaphragms and miscellaneous parts out of composites. The only thing I am missing right now are some shaft connecters that match the size of the Pac Sci motor shafts. I'm planning on a sealed two-way system. One driver will operate full range, but at restricted excursion for lower frequencies. The second driver will augment the lower frequencies. This is a bit of a rube goldberg arrangement--your system with the passive radiators is a lot simpler. However, I plan on using DSP to do the equalization and phase compensation and from my experience, this is much easier to do in a sealed system. John ========================================================================= From: "Danielak, Robert M" Subject: [JN] RE: Date: Tue, 04 Jan 2000 09:32:19 -0500 Source: Sound Digest Archive v02.n384 hey blackie, happy new year! how's the new family? please count me in for nynoise. i have a bunch of things i could show and a couple more on the drawing board. there's that bunch of 1626 amps that we took to valerie's but i was thinking of trying the other end of the spectrum this year. instead of the *lowest* power amp maybe we'll shoot for the *highest*... ;) any more thought on the *jam-session* this year. in that case i could bring amps that i made and guitars that rich made... ;) talk to you soon! bob.d. > ---------- > From: blackie[SMTP:tubesville@yahoo.com] > Reply To: blackie@tubesville.com > Sent: Tuesday, January 04, 2000 6:17 AM > To: joe list; me; jc morrison > > howdy joe drinkers > > i am making a last call for submissions to nyNOISE > audio/design exhibition 2000 > > jc and I hope to have some concrete idea of how this > baby is gonna work within a couple of weeks > > just to reiterate: > no special requirements, just try not to be boring > > 2nd Sat of March 2000, jc's loft in hoboken, > attendance by invite, email me with questions or > submissions please... > > thanks > > please note, i will solicit addresses for invites > *after* we sort out the exhibitors...these will be > first come first served, a total of 250 attendees > (all we have room for) > > > > > > > ===== > blackie > blackie@tubesville.com > www.tubesville.com > __________________________________________________ > Do You Yahoo!? > Talk to your friends online with Yahoo! Messenger. > http://messenger.yahoo.com > ========================================================================= From: Roscoe Primrose Subject: Re: [JN] Re: Date: Mon, 17 Apr 2000 11:57:42 -0400 Source: Sound Digest Archive v02.n523 evaguido wrote: Snip... > > >Besides the first circuitry in the PCM63 after the data input pad is > >some kind of D-type flip flop anyways, probably in a serial to parallel > >converter. > > Yes, and which clock is used to clock that flipflop ? The bit clock. Which is a clock where jitter is much less important. It's the word clock, where all those latched bits are sent simultanously to the DAC that has the most stringent jitter requirements. Peace - -- Roscoe Primrose -- mailto:roscoe@aiko.com -- http://www.aiko.com/roscoe "Once in a while you get shown the light In the strangest of places if you look at it right." Robert Hunter "640K ought to be enough for anybody" , Bill Gates, 1981 ========================================================================= From: evaguido Subject: [JN] Re: Date: Mon, 17 Apr 2000 17:34:25 +0200 Source: Sound Digest Archive v02.n523 At 11:24 17/04/2000 +0200, thomas.mayer@philips.com wrote: >Guido, Thomas, >> Agreed but that is in most cases better than forcing another jittery >> current into an IC. Substrate coupling mechanisms then again take care of >> jitter at the conversion..... > >I agree that the conversion process might be influenced by the >way data arrives at it's inputs, via substrate or supply coupling >mechanisms. But to argue if one or the other is better seems to >be speculation to me. I agree. The point is that I cannot find an experiment to separate those.... (reclocking gives additional circuit, non-reclocking may interfere at the substrate level) >One could also argue the other way around, >that a slightly jittery data couples a more smeared out noise >spectrum into the supply than a rigidly reclocked one. Yes, but the lower the energy content of jitter, the better.... >Besides the first circuitry in the PCM63 after the data input pad is >some kind of D-type flip flop anyways, probably in a serial to parallel >converter. Yes, and which clock is used to clock that flipflop ? >So why double up that flip flop outside ? I would think >that the additional flip flop on the board potentially does more harm. I do not know, more than experiments giving preference to "double" reclocking >> But I am not sure if I can get a clock transfered between two boxes, and >> remain the 1 ps jitter requirement > >Huh ??? 1ps jitter requirement ? The whole purpose of my scheme is to >have very relaxed jitter requirements on the interface between DAC >and transport. The 11.289MHz clock has somewhere around 80ns cycle >time. Substracting all the set up and hold timing requirements this >still leaves a HUGE margin for allowable jitter in the 10s of ns range! If you take data correctness as the requirement: Yes At the DAC (20 bits, 8 times oversampled) it needs to be around 1 ps >The resynchronisation mechanism in front of the DAC removes that jitter To what extent ? Sufficient ? How many chokes or additional filters do you have in your amps ? Sufficient ? Have fun Guido >Ciao ... Thomas > > ========================================================================= From: evaguido Subject: Re: [JN] Re: Date: Mon, 17 Apr 2000 20:05:19 +0200 Source: Sound Digest Archive v02.n523 Roscoe Thanks for you reply. I am aware of the importance of the wordclock. However, our ecxperience and measurements show that reclocking any digital (synchronised) signal that enters a PCM63 improves the whole. Given part of my daily work as EMC Engineer (currently on silicon) I am not surprised.... In theory you are right, though practice is different, once many parasitics are involved. regards, - - Guido At 11:57 17/04/2000 -0400, Roscoe Primrose wrote: >evaguido wrote: > >Snip... > >> >> >Besides the first circuitry in the PCM63 after the data input pad is >> >some kind of D-type flip flop anyways, probably in a serial to parallel >> >converter. >> >> Yes, and which clock is used to clock that flipflop ? > >The bit clock. Which is a clock where jitter is much less important. >It's the word clock, where all those latched bits are sent >simultanously to the DAC that has the most stringent jitter >requirements. > >Peace >-- >Roscoe Primrose -- mailto:roscoe@aiko.com -- >http://www.aiko.com/roscoe > >"Once in a while you get shown the light >In the strangest of places if you look at it right." Robert Hunter > >"640K ought to be enough for anybody" , Bill Gates, 1981 > > ========================================================================= From: evaguido Subject: [JN] Re: Date: Sun, 09 Jul 2000 22:47:33 +0200 Source: Sound Digest Archive v02.n599 Andrew It can be done using a voltmeter, but these are also sensitive for the low frequency variations due to the mains variations and/or variations due to the load. These variations are low frequency, making reading difficult. A highpass at 20 Hz or so helps. Easier work is taking an oscilloscope, if you have one at hand. Always realise yourself that high DC voltages may damage the instruments you use: AC coupling using a caacitor may be required. Enjoy = Guido At 13:24 09/07/2000 -0700, Andrew Brandon wrote: >Hi folks, > >How do I measure noise "ripple?" in my power supplies. >Can it be done using a vom? I see where people quote >"10 mv" or whatever figure they have measured. >Thanks > >Andrew > >__________________________________________________ >Do You Yahoo!? >Get Yahoo! Mail – Free email you can access from anywhere! >http://mail.yahoo.com/ > > ========================================================================= From: StepHydro@aol.com Subject: [JN] Re: Date: Fri, 25 Aug 2000 10:41:44 EDT Source: Sound Digest Archive v02.n641 In a message dated 00-08-25 10:23:20 EDT, andersedenholm@cableinet.co.uk writes: << Hi Joes, any one have any info on this tube. Apparantly made by Svetlana. A friend got hold of a bunch, useable for audio? >> Anders, I suspect that is a great tube. Uhhhhh, does it have a type identifier???? Cheers/Carron :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) :-) ========================================================================= From: Roscoe Primrose Subject: [JN] Re: Date: Fri, 15 Dec 2000 14:05:25 -0500 Source: Sound Digest Archive v02.n760 TORSTEN.LOESCH@enhar-ha.nthames.nhs.uk wrote: > Quite impressive for a box of tricks costing less than $ 1,000. BTW, in a digital loop between CD > Transport and DAC the UC is essentially sonically neutral, without audible contribution unless the EQ is > employed. I'm currently running my BSS OmniDrive Compact Plus directly from the digital out on my transport with similarly good results. Unfortunately, the BSS doesn't have digital outs (yet, I plan to take a look inside about providing three after the new year) but it is still quite neutral. Havn't played with the analog ins yet, have to finish my Teres first... > So for anyone with Fullrange drivers that have sonic problems with their response and room in a fu lly > digital system with separate X-Port and DAC I cannot recommend the UC high enough. For a prima rily I'd been thinking the same thing, but hadn't been willing to shell out the bucks to find out. > analogue system like my own the case is not as clear-cut. The Converters and analogue stages in th e UC > should ideally be a lot better, though they seem adequate. One could of course use true high resolution > external converters if one wants to, looking at the Datasheets it seems that especially the D2A > converter used in the UC is the limiting factor to sound quality. I'd also thought about that. I don't think I will use an external A/D converter with the BSS, at least not initially, it operates at 96/24 (probably more like 20bits useable) from analog inputs, so I'll see how that works out first. Peace - -- Roscoe Primrose -- mailto:roscoe@aiko.com -- http://www.aiko.com/roscoe "Once in a while you get shown the light In the strangest of places if you look at it right." Robert Hunter "640K ought to be enough for anybody" , Bill Gates, 1981 ========================================================================= From: sschenkel@juno.com Subject: [JN] Re: Date: Sun, 17 Dec 2000 21:08:59 -0800 Source: Sound Digest Archive v02.n762 Does that include speakers too? Schenkelini On Sun, 17 Dec 2000 10:25:57 -0800 (PST) blackie writes: > An Open Invitation to Designers… > > …to submit work for inclusion in a new Audio/Design > Collection, showing in a large finished loft space / > listening room in Hoboken. The work will be offered > for sale to the listening public on a consignment > basis. > > I am opening this space as an alternative to > traditional high end audio stores. It will be called > NOISE Audio/Design Space (NADS), and is not directly > affiliated with nyNOISE Audio Design Exhibition. Our > primary purpose will be to provide an outlet for the > sale of work built by designers outside the existing > commercial audio structure. Our secondary purpose > will be to foster dialog, exchange of ideas, and > possible collaboration among the underground design > community. > > It is my feeling that there is an untapped market for > audio / design that is unencumbered by the typical > corporate approaches of "cost vs. price" analysis, > committee based design decisions, and mass > marketability - alternative designs informed mainly > by a pursuit of sonic excellence and personal > aesthetics. My goal will be to select a group of this > work and provide a context for the work based on the > artist / gallery model rather than the traditional > corporation / retail store system. It is my hope that > press and public will respond positively. > > Any designers interested in being considered for > inclusion in this venture, please contact me by email > for particulars. > > Thanks- > Blackie Pagano > blackie@tubesville.com > www.tubesville.com > > ===== > blackie > blackie@tubesville.com > www.tubesville.com > > __________________________________________________ > Do You Yahoo!? > Yahoo! Shopping - Thousands of Stores. Millions of Products. > http://shopping.yahoo.com/ > > ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/tagj. 0000 ========================================================================= From: "Multi-Volti Devices" Subject: [JN] 0.1 uF 450 v~ (that's vac) paper in mineral oil Date: Mon, 19 Apr 1999 03:34:57 -0400 Source: Sound Digest Archive v02.n129 Hello: I have some NOS Matsushita Industrial paper in mineral oil (labeled no PCB's) capacitors, 0.1 uF 450 Vac. Ceramic body, fairly long leads. A friend who is a capacitor applications engineer with a large film cap company estimates a 'good quality' 450 vac part may have a DC rating as high as 1100 VDC. I am pondering how I can safely test these to estimate a DC rating. I don't have access to a current limited DC hi-pot (dielectric withstand) tester (only have access to an ac unit, which would just ruin the parts). I was hoping I could observe leakage current at increasingly higher voltages (analogous to diode reverse breakdown), and stop increasing voltage when I start to get a change in IDC. Any ideas on how to estimate the DC capability, and any ideas what would be a fair (to me) price to sell some for? I have more than I anticipate needing, but don't want to 'give them away' naively. I'd like to get a fair price for them. (Roughly 60-70 left). Thanks Murray ========================================================================= From: Remco Stoutjesdijk Subject: [JN] 01 vs 26 ? Date: Tue, 24 Apr 2001 15:27:58 +0200 Source: Sound Digest Archive v02.n873 Hi, Whilst pondering a new preamp and trying to decide which tube to use, I noticed the many similarities between the 01 and the 26. However while the 26 is used in a lot of preamps, I hardly ever see the 01. Why? From the datasheet it seems just a bit more fragile, but in preamps it should work just fine. I have a pair of 301s that measure and match very well and seem fine candidates for a nice WVOT preamp. Unless... well, I'm curious why not! Regards, Remco - -- http://www.ultranalog.com ========================================================================= From: Jim de Kort Subject: Re: [JN] 01 vs 26 ? Date: Tue, 24 Apr 2001 17:05:02 +0200 Source: Sound Digest Archive v02.n874 Hoi Remco, Whilst pondering a new preamp and trying to decide which tube to use, I >noticed the many similarities between the 01 and the 26. However while >the 26 is used in a lot of preamps, I hardly ever see the 01. Why? From >the datasheet it seems just a bit more fragile, but in preamps it should The 01A is very similar to the 30, Rp of 10K etc... Jim de Kort jim@vt52.com http://www.vt52.com http://www.ux226.com ========================================================================= From: SBench@aol.com Subject: Re: [JN] 01 vs 26 ? Date: Tue, 24 Apr 2001 22:12:13 EDT Source: Sound Digest Archive v02.n874 In a message dated 01-04-24 09:31:29 EDT, remco@ultranalog.com writes: > Whilst pondering a new preamp and trying to decide which tube to use, I > noticed the many similarities between the 01 and the 26. However while > the 26 is used in a lot of preamps, I hardly ever see the 01. Why? Hi, In addition to the excellent notes also posted, I've found the 01A to be better sounding than 26, but only when operated on reduced filament voltage. (see distortion curves of 01A starved filament on my web pages at http://members.aol.com/sbench101) 01A is sometimes harder to find, and it can be a bit microphonic, but very nice sounding. Best Regards, Steve ========================================================================= From: William Gardner Subject: [JN] 025 sale Date: Sun, 02 Jan 2000 23:29:30 -0600 Source: Sound Digest Archive v02.n559 For sale : Pair magnequest 025 OPT . New . $225.00 Thanks William Gardner ========================================================================= From: peufeu@free.fr Subject: [JN] $0.5 cable recipe Date: Fri, 22 Dec 2000 15:53:50 +0100 (MET) Source: Sound Digest Archive v02.n768 Hi people, This is a mad scientists' recipe for strange, yet interesting, audio cables : ingredients : - uninsulated plain standard copper wire from the junk pile (or strip the insulation from an insulated wire) - some of this PCB breadboard which you use for wrapping and making prototypes that smoke in the making : - cut small chunks of breadboard, rectangular pieces of about 1.5 cm. long and 3 mm wide (with just one row of holes in the middle). - cut your wire in 2 equal lengths, then thread the little PCB rectangles on it, using them as spacers to keep the two wires apart (put each wire in the holes at each side) - solder the wire to the breadboard pieces to make the thing hold together nicely Now you have two bare wires kept apart by little spacers. If you want a stereo cable, you can do it with three wires, with ground in the center of the spacers. Twist it so the wire pair does a half turn for every spacer (there should be one every 10 cm or so) Solder it to your favorite connectors and listen !!! I won't tell you how it sounds. It is interesting. Given the cost, I encourage everybody to try this and report your experiences on the mailing list... You can also do this with your speaker cables (no shieldong problems), your power supplies, etc... Have fun, and merry christmas ! ========================================================================= From: "Joerg Heyer" Subject: [JN] 0.5 F Capacitors (16V) Date: Thu, 28 Sep 2000 16:14:22 EDT Source: Sound Digest Archive v02.n677 Hi, does anybody know a source for large value capacitators (o.33 - 1F) which are, *aehemm*, cheap (the schematic calls for 4 of them)? Thanks Joerg _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ========================================================================= From: "David R. McGown" Subject: Re: [JN] 0.5 F Capacitors (16V) Date: Thu, 28 Sep 2000 19:13:07 -0400 (EDT) Source: Sound Digest Archive v02.n677 On Thu, 28 Sep 2000, Joerg Heyer wrote: Try an shop specializing in automobile sound. Here in the US, Parts Express carries 1F capacitors as storage caps for high power custom auto sound installations. They have to be at least 12V. Also, I think Panasonic has some 1F 5V caps for computer power storage, if they are cheap enough you can always use 3 in series to get 15V. These are available from Digikey. David > Hi, > > does anybody know a source for large value capacitators (o.33 - 1F) which > are, *aehemm*, cheap (the schematic calls for 4 of them)? > > Thanks Joerg > _________________________________________________________________________ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. > ====================================================================== David R. McGown dmcgown@megacats.com -o-O-o- Home: (301)946-3027 13100 Wilton Oaks Dr. Work: (703)416-1240 Silver Spring, MD 20906 ========================================================================= From: evaguido Subject: Re: [JN] 0.5 F Capacitors (16V) Date: Fri, 29 Sep 2000 09:26:03 +0200 Source: Sound Digest Archive v02.n678 Joerg do you realy mean 1 F ? The only onesd I know are back ups for RAM memory. These are 5.5 V, not cheap and I use them as back up in the backlight of bikes.... Guido At 16:14 28/09/2000 EDT, Joerg Heyer wrote: >Hi, > >does anybody know a source for large value capacitators (o.33 - 1F) which >are, *aehemm*, cheap (the schematic calls for 4 of them)? > >Thanks Joerg >_________________________________________________________________________ >Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > >Share information about yourself, create your own public profile at >http://profiles.msn.com. > > > ========================================================================= From: "Joerg Heyer" Subject: Re: [JN] 0.5 F Capacitors (16V) Date: Sat, 30 Sep 2000 14:36:02 EDT Source: Sound Digest Archive v02.n681 Hi, thanks for the help and suggestion! Since finally taking a plunge at analog again, I settled on the Hiraga MC - -prepre for a starter for my (yet to order) Denon DL103. The schematics can be found at the Bonavolt website http://www.infomaniak.ch/~bonavolt/prepre.htm. The caps 16V 0.5 F are for the battery power supply ( I like the idea of being independent of the power line, I hope to avoid electroexecuting me on my first non kit amp project). I will try other power supplies later but I wanted to start with a "original proven" design. Joerg _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. ========================================================================= From: "P. Caillaud" Subject: Re: [JN] 0.5 F Capacitors (16V) Date: Sat, 30 Sep 2000 23:57:14 +0200 Source: Sound Digest Archive v02.n681 Hi, If I can be of any advice, you don't need such a huge capacitance when using battery power supply. Batteries are slow, but not to the point of putting caps that can keep the amp running for several minutes once you unplug the batteries... It looks like overkill to me. Having good quality caps is more important than having 1 Farad. I would suggest low inductance 63000 uF types with MKP bypassing and anti-vibration treatment (all caps are microphonic, some more than others). This will save you much dough, that you will re-invest at once in MAT-03 precision matched low-noise transistor pairs to replace the BC560C's. Overall you should get much better performance from this. Good luck ! Joerg Heyer wrote: > Hi, > > thanks for the help and suggestion! > > Since finally taking a plunge at analog again, I settled on the Hiraga MC > -prepre for a starter for my (yet to order) Denon DL103. > The schematics can be found at the Bonavolt website > http://www.infomaniak.ch/~bonavolt/prepre.htm. > > The caps 16V 0.5 F are for the battery power supply ( I like the idea of > being independent of the power line, I hope to avoid electroexecuting me on > my first non kit amp project). I will try other power supplies later but I > wanted to start with a "original proven" design. > > Joerg > > _________________________________________________________________________ > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. > > Share information about yourself, create your own public profile at > http://profiles.msn.com. - -- _________________________ Pierre-Frédéric Caillaud peufeu@free.fr 32 Passage Gonin 69001 Lyon France 06 61 52 75 96 04 78 43 15 94 1111 ========================================================================= From: "Greg Monfort" Subject: "100+dB / 1W speaker". Was: Fw: [JN] System 1:Step 4, Speakers........... Date: Fri, 11 Feb 2000 14:10:19 -0500 Source: Sound Digest Archive v02.n445 Hi, I guess I should have changed the subject line to: "100+dB / 1W speaker". I was 'thinking out loud' so to speak WRT Peter's desire for a 1W ~full range speaker. I couldn't sleep and found it an interesting diversion. WRT the System 1, I'm for a two way horn system down to ~100Hz, with a multiple driver bass unit to keep the size semi-reasonable, but after witnessing the BassList Speaker design forum / fiasco I'm steering clear of this one too. :^)) - ------------- Jean-Michel Le Cleac'h wrote: > > While necessary, frequency response and cut-off slope are not the only > things to consider. ======== You bet! Amplitude, phase shift, etc. ======== > How is the impedance inside the reproduced interval of frequency? is > another important question. ======== Why so in a wide range driver? ======== > Also a TEF to look for possible parasitic resonnances (inside the air > volume between basket and membrane, inside the basket,etc.) is necessary. ======== This is well beyond my capabilities at present, and normally isn't considered in most DIY, but would be nice. ======== > IMHO our Joenet's loudspeakers system should present a constant impedance > from 100Hz to 10000Hz. ======== I'm not sure why, with my idea at least, but a zobel should take care of it. - ------------- Gordon wrote: > Actually if you had the T/S parameters for this you would know that it > would be more like 0.7CUf and tuned to 125 is about as low as you can go. ======== Again, if the info at http://www.netspace.or.jp/~eifl/eifl/export/export2.htm is fairly accurate, Vas Qes, Qms can be guesstimated from it's Qts, Sensitivity ratings. With my assumptions, BoxPlot predicted close enough to your numbers for a Q =.7 box, but that's hardly all the BW this puppy can do, or any other driver for that matter. With a power limited EBS (extended bass shelf) alignment (and <2W is pretty limited IMO!) there's lots more usable BW to be had, especially when a second driver of the same type is added to help fill in the bottom octaves. A little room gain helps to finish it off. An EBS also lowers system Q, reduces phase shift, and gives a ~flat amplitude response over a wider BW (with a second driver). It's my understanding, and experience, that these are all pluses in the pursuit of accurate sound reproduction. Tradeoffs are dramatically increased box size, non flat FR, though in this design I see neither one being an issue. TIA for more insight, GM ========================================================================= From: "Le Cleac'h Jean-Michel" Subject: Re: [JN] 100 mu.sec. square wave - RIAA filtered Date: Thu, 16 Nov 2000 18:35:32 +0100 Source: Sound Digest Archive v02.n735 This is a multi-part message in MIME format. - ------=_NextPart_000_000F_01C04FFC.0048D560 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Hello, As since several days it is very difficult to use xdrive from France, I send to the whole list a very small attachment (4.71k) that contains a 2 color .gif graph showing a part of a square signal through an inverse RIAA network (the one I described previously). I could have shown the result of a longer duration square signal but in fact it only differs by the length of the nearly horizontal part of the signal, so you can easily prolongate linearly the actual signal to obtain a longer one. 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[JN] 100W AKSA Amp Date: Fri, 24 Aug 2001 11:05:48 -0400 Source: Sound Digest Archive v02.n954 Hi all, Wondering if anyone on the list has already own one. How does it match up to the 55 watter? - -- Johari Yip =================== j45yip@netscape.net =================== __________________________________________________________________ Your favorite stores, helpful shopping tools and great gift ideas. Experience the convenience of buy ing online with Shop@Netscape! http://shopnow.netscape.com/ Get your own FREE, personal Netscape Mail account today at http://webmail.netscape.com/ ========================================================================= From: Larry Van Wormer Subject: [JN] $10 CDnow coupon Expires 2/15 Date: Wed, 10 Feb 1999 20:45:37 -0500 Source: Sound Digest Archive v02.n040 http://www.cdnow.com/cgi-bin/mserver/redirect/leaf=from=vbd:u:imu:nht:d A nice deal, $10 off an order of $20 or more. I just ordered a couple of CD's using it. Larry Van Wormer ========================================================================= From: Allen Wright Subject: [JN] 10" driver recommendation? Date: Fri, 23 Apr 1999 04:37:05 -0400 Source: Sound Digest Archive v02.n130 Lady and Gents, Following a failed commercial venture, a good friend has a pair of impressive looking (and very expensive) 70 liter speaker boxes needing a suitable full range/coaxial 10 inch driver, hopefully of highish dB/watt sensitivity. I have suggested the Tannoy 10" coaxial, going on the 12's and 15's I have heard and liked very much. But I have never heard them. Any ear reports on the 10", or any other suggestion? The boxes are currently sealed, but a reflex port could easily be fitted, conversion to a horn (front or rear) is not possible... The box design will not allow a separate tweeter and still look as stunning as it does, hence the full range/coax request. Thanks in advance for any experiences/suggestions. A European sourced device would be preferred but is not essential. Allen (VSE) PS We have a REAL web address now: www.vacuumstate.com ========================================================================= From: "=?ISO-8859-1?Q?Torbj=F8rn_Lien?=" Subject: Re: [JN] 10" driver recommendation? Date: Fri, 23 Apr 1999 20:06:43 +0200 Source: Sound Digest Archive v02.n130 Hello Allen, all,- Allen Wright wrote: > Lady and Gents, > Following a failed commercial venture, a good friend has > a pair of impressive looking (and very expensive) 70 liter > speaker boxes needing a suitable full range/coaxial 10 inch > driver, hopefully of highish dB/watt sensitivity. > > I have suggested the Tannoy 10" coaxial, going on the 12's > and 15's I have heard and liked very much. [snip!] I don't get to post or participate much these days,-(The family + I is moving to a new appartment,-so I'm buried in my junk and stash these days, trying to sort through it.....(wondering what evil childhood experiences that made me collect all this junk..) But,-amongst that is a pair of the 10" 'er Goodmans axiom 80. (Mine are not for sale..Took me 10 years to get an old pair..) IMNHO this is easily the most well-balanced, musical and extended full-range driver I've yet experienced,- I think it beats the Lowther-consept clearly,-when it comes to balance, versatility,finesse,-especially on vocal.But they are *somewhat* thin in the bass,-Not much there as the cantilever surround makes for an extremely low Fres ,-with a following very lo-Q. If they still are made I don't know,- but Godmans produced a series for the Asian marked in the mid/late eighties I think. At that time it was possible to get these in Denmark,- for approx. 2400 Dkr. each? (Kurt?) Maybe other know something on the wherabouts of the Axiom 80's these days? My 2 oeres worth. (100 oere=1 Nok= 0,128 USD) Regards Torbjoern Lien, Norway > > > > ========================================================================= From: Allen Wright Subject: Re: [JN] 10" driver recommendation? Date: Sun, 25 Apr 1999 07:20:28 -0400 Source: Sound Digest Archive v02.n131 Torbjoern wrote: >>>But,-amongst that is a pair of the 10" 'er Goodmans axiom 80. (Mine are not for sale..Took me 10 years to get an old pair..) IMNHO this is easily the most well-balanced, musical and extended full-range driver I've yet experienced,- I think it beats the Lowther-consept clearly<<< I know them well, and almost had a pair for myself - but the seller pulled out of the deal when he found what these puppies are worth in Japan! They do sound beautiful but would be far too fragile for my friends usage, he tends to play things loud. Great suggestion though! Allen (VSE) PS Anyone heard a Tannoy 10" coax? ========================================================================= From: Torsten.Loesch@enhar-ha.nthames.nhs.uk Subject: Re(2): [JN] 10" driver recommendation? Date: 26 Apr 1999 11:15:32 +0000 Source: Sound Digest Archive v02.n131 Hi there, Allen (VSE) wrote: > PS Anyone heard a Tannoy 10" coax? I have (fairly regulary actually) heard the Tannoy 10" Units for Studio-use.... Reasonably nice, but not great.... How about trying these Boxes with a Normal decent Wideband 10" (JBL 2123?) and a Horn sitting on top of them.... I know - boring, but works well.... Later Thorsten ========================================================================= From: "Craig Anderson" Subject: Re: [JN] 10k:10k input tranny? Date: Fri, 31 Aug 2001 21:42:19 -0600 Source: Sound Digest Archive v02.n958 Funny you should ask, I placed an order for one of these today: WSM 10k/10k 0.5 Watt Matching Transformer 10k ohms to 10k ohms http://www.edcorusa.com/magnetics/audio/WSM/WSM10k-10k.htm $7.56 My first purchase here, they have an 800 order line and sold me qty 1. I'm planning to build a single channel headphone amp and try one of these for a stereo to mono input. EM6410 Stereo to Mono Coupling Transformer Stereo line level to mono line level $7.09 - ----- Original Message ----- From: "Steven S" To: Sent: Friday, August 31, 2001 8:38 PM Subject: [JN] 10k:10k input tranny? > > Anyone know where i can get a small and/or good 10k:10k input > tranny. Putting together a headphone amp to fiddle with and i cant seem to > find what i'm looking for from the usual sources. > > > > Steven St.Laurent ::: stevensl@mindspring.net ::: 403forbidden.net > > "Outlook not so good." > That magic 8-ball knows everything! > I'll ask about Exchange Server next. > > > ========================================================================= From: Steven S Subject: [JN] 10k:10k input tranny? Date: Fri, 31 Aug 2001 22:38:35 -0400 (EDT) Source: Sound Digest Archive v02.n958 Anyone know where i can get a small and/or good 10k:10k input tranny. Putting together a headphone amp to fiddle with and i cant seem to find what i'm looking for from the usual sources. Steven St.Laurent ::: stevensl@mindspring.net ::: 403forbidden.net "Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next. ========================================================================= From: "Ellen Oler" Subject: [JN] 10 monkeys eat a free lunch Date: Sun, 05 Nov 2000 22:09:16 -0500 Source: Sound Digest Archive v02.n722 I *think* that what would happen is that they would reach an equilibrium somewhere. You couldn't hold either tube to a fixed op point as if it were attached to a stiff supply, you could just get it set to a desired op point by experimentation, I imagine. Imagine using one of the Doc B C4S boards set to 30mA instead of another tube. Well, the tube attached to the C4S would reach an equilibrium where it was drawing the current it was permitted to draw - the DC op point would be forced to shift - I think??? With the two tubes I imagine the voltage drop across each one would shift (from where it would be otherwise in a "free running" setup) until they were both working at the same current. What this does to the sound of course is anybody's guess. In fact the whole thing is just a guess . . . I bet as you twiddled that 300 ohm pot you'd get the cathode of the 10 running up and down to adjust. Sounds like a fun sport! - -j, voting for Al (M.? G.?) in a couple of days, then breathlessly awaiting the Canadian results >what happens if one of the tubes is not matched in current draw to the other? > >in otherwords, if the 10 is running 30ma and the 6c45 is biased to run >35ma??? or take it the other way and let the 10 run 35ma and the russkie >only lets 30ma go through... > >well we know both tubes will have the same current, the question becomes is >that how much current they would be running if the other tube were not >there? > >its an interesting question, what happens to a tube when you force it away >from its characteristics? can this be done... > >i bet a small say 300 ohm or so pot in series with the choke will let you >tune the sound and nail the operating point... and a 500 ohm DCR choke is >easy enough to source for this... otherwise you got 6500 turns of #35 on an >EI87 nickel core.... > >in any event at some point one of the tubes is gonna current limit the >other... ========================================================================= From: "Epstein, Jeremy" Subject: [JN] 10 monkeys eat a free lunch - design idea/questions Date: Fri, 3 Nov 2000 10:16:03 -0500 Source: Sound Digest Archive v02.n720 Design idea: Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for a seperate cathode resistor from the cathode of the 10 to ground: all the 10's juice flows through the driver tube. Design questions: Does there need to be a bypass cap from the cathode of the 10 to prevent regeneration? As I look at it, the driver tube would serve as a cathode impedance for the 10 equal to the vector sum of the impedance of the driver load choke plus the plate impedance of the driver tube plus any resistance needed in series to get correct bias (does some portion of this get multiplied by the mu of the bottom tube too?) hence the 10 would suffer a large amount of regenerative feedback. True or false? Also as I see it, the bypass could either go from cathode to B+ a la Ultrapath or cathode to ground as is more conventionally done. True or false or not necessary because the first answer is "false"? If the bypass cap is necessary would it need to be largish (because the total cathode impedance is smallish, say <2K) or small (because there is in fact a "times mu" term that makes the effective impedance large)? Proposed schematic for reference: (fixed width font please): B+ | C|C---> C|C C|C---> | 10 _|_ ...-----+ /^\ | | | | UUU | bypass?----* | (* = center tap of filament < | transformer) DCR < | of this < | R and | | choke C| | totals C| | ~860 C| | +------+ 6C45Pi _|_ - -----+-----... C| --, C| | C| _|_ C| - | | 2 x AA battery V _|_ - | V Note that this could be built as a one-resistor per channel amp (grid stopper on 6C45pi), if a battery is used to bias the driver and the plate choke DCR is made 860 ohms, and a grid choke is used on the input. Figure a filtered supply of 595 V, drop 5V in the OPT, drop 395 across the 10, drop 30 (DCR = 860, I = 35mA) to the plate of the 6C45Pi where the voltage will be 165V. (I got this 10 op point from a Joe who oughta know.) - -j ========================================= Jeremy Epstein........jepstein@ndbcap.com ========================================= ========================================================================= From: TubeGarden@aol.com Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions Date: Fri, 3 Nov 2000 11:20:09 EST Source: Sound Digest Archive v02.n720 - --part1_db.bbbb1b8.27343fb9_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Hi If you replace the two AA batterries with a 6AS7 with its grip tied to the plate (as a diode), you can live without the bypass C. In my amp, the 6AS7 so wired drops 4.4 volts at 40 mA, so it will be fairly close at 35 mA. Happy Ears! Al B^} - --part1_db.bbbb1b8.27343fb9_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: 7bit Hi

If you replace the two AA batterries with a 6AS7 with its grip tied to the
plate (as a diode ), you can live without the bypass C.

In my amp, the 6AS7 so wired drops 4.4 volts at 40 mA, so it will be fairly
close at 35 mA.

Happy Ears!
Al        B^}

- --part1_db.bbbb1b8.27343fb9_boundary-- ========================================================================= From: "Epstein, Jeremy" Subject: RE: [JN] 10 monkeys eat a free lunch - design idea/questions Date: Fri, 3 Nov 2000 12:06:43 -0500 Source: Sound Digest Archive v02.n720 > Hi Jeremy, > > wow, a tube related technical question on the JoeNet, > long time no see. Sorry. DEMOCRACY SUCKS!! UP WITH IMPERIALISM!! JUST BECAUSE YOU'RE PARANOID DOESN'T MEAN THEY'RE *NOT* OUT TO GET YA!! SEX PISTOLS RULE!! Better? > >Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, > so no need for > >a seperate cathode resistor from the cathode of the 10 to > ground: all the > >10's juice flows through the driver tube. > > Sounds like a nice idea! I got some VT-25's for my birthday, hence the thought. > >Does there need to be a bypass cap from the cathode of the > 10 to prevent > >regeneration? > > Absolutely. You will get no output signal from this amp > without a cathode bypass. OK. > >If the bypass cap is necessary would it need to be largish > (because the > >total cathode impedance is smallish, say <2K) > > If memory serves me right then the impedance seen when > looking into the cathode is (Rp+Ra)/(mu+1). > The size of bypass cap needed will a bit less then in a conventional > cathode biased stage but not by much so. So pretty large the way I like to do it, say 100uF or thereabouts. > I hope the AA-batteries you mentioned in your schematic consists > of NiCd cells. Normal batteries will blow up! But of course! Anecdotal research shows that NiCads will survive 70mA of charging current for at least many months. Thanks Manfred! - -j ========================================= Jeremy Epstein........jepstein@ndbcap.com ========================================= ========================================================================= From: "Larry D. Moore" Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions Date: Fri, 03 Nov 2000 12:33:30 -0500 Source: Sound Digest Archive v02.n720 Don't like monkey amps. Tried it. It simply moves the problem from one location in the circuit to another. Think making the cathode bypass cap the most critical component in the amp signal section. To me, do seperate supplies, diode bridge, or a cap. I mean I'd rather pick a low value cap that sounds good than a big one that sounds bad. Think 0.1uF versus several orders of magnitude bigger. Granted it will change the soundstage, but if you listen long enough it is simply wrong. LDM At 10:16 AM 11/3/00 -0500, you wrote: >Design idea: > >Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for >a seperate cathode resistor from the cathode of the 10 to ground: all the >10's juice flows through the driver tube. > >Design questions: > >Does there need to be a bypass cap from the cathode of the 10 to prevent >regeneration? As I look at it, the driver tube would serve as a cathode >impedance for the 10 equal to the vector sum of the impedance of the driver >load choke plus the plate impedance of the driver tube plus any resistance >needed in series to get correct bias (does some portion of this get >multiplied by the mu of the bottom tube too?) hence the 10 would suffer a >large amount of regenerative feedback. True or false? > >Also as I see it, the bypass could either go from cathode to B+ a la >Ultrapath or cathode to ground as is more conventionally done. True or false >or not necessary because the first answer is "false"? > >If the bypass cap is necessary would it need to be largish (because the >total cathode impedance is smallish, say <2K) or small (because there is in >fact a "times mu" term that makes the effective impedance large)? > > >Proposed schematic for reference: > >(fixed width font please): > > > B+ > | > C|C---> > C|C > C|C---> > | > 10 _|_ > ...-----+ > /^\ | > | | | > UUU | > bypass?----* | (* = center tap of filament > < | transformer) > DCR < | > of this < | > R and | | > choke C| | > totals C| | > ~860 C| | > +------+ > 6C45Pi _|_ >-----+-----... > C| --, > C| | > C| _|_ > C| - > | | 2 x AA battery > V _|_ > - > | > V > > >Note that this could be built as a one-resistor per channel amp (grid >stopper on 6C45pi), if a battery is used to bias the driver and the plate >choke DCR is made 860 ohms, and a grid choke is used on the input. > >Figure a filtered supply of 595 V, drop 5V in the OPT, drop 395 across the >10, drop 30 (DCR = 860, I = 35mA) to the plate of the 6C45Pi where the >voltage will be 165V. (I got this 10 op point from a Joe who oughta know.) > >-j > >========================================= >Jeremy Epstein........jepstein@ndbcap.com >========================================= > > ========================================================================= From: MHuber@t-online.de (Manfred Huber) Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions Date: Fri, 03 Nov 2000 17:48:52 +0100 Source: Sound Digest Archive v02.n720 Hi Jeremy, wow, a tube related technical question on the JoeNet, long time no see. >Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for >a seperate cathode resistor from the cathode of the 10 to ground: all the >10's juice flows through the driver tube. Sounds like a nice idea! >Does there need to be a bypass cap from the cathode of the 10 to prevent >regeneration? Absolutely. You will get no output signal from this amp without a cathode bypass. Imagine you sit in the #10 and lock out through the cathode wire. What do you see first? The choke! This means there is a very large ac impedance in between the cathode and GND. The other way around: Imagine a signal on the plate of the 6C45. This signal is also on the grid of the #10. Because of the choke there is no ac current through the tubes and the #10 cathode will follow it's grid! Viewed from this perspective it looks like a 'choke-enhanced' SRPP stage. The bypass cap 'shorts' the #10 cathode to gnd and thus allows the #10 to modulate it's plate current. >As I look at it, the driver tube would serve as a cathode >impedance for the 10 equal to the vector sum of the impedance of the driver >load choke plus the plate impedance of the driver tube plus any resistance >needed in series to get correct bias (does some portion of this get >multiplied by the mu of the bottom tube too?) hence the 10 would suffer a >large amount of regenerative feedback. True or false? Exactly true! >Also as I see it, the bypass could either go from cathode to B+ a la >Ultrapath or cathode to ground as is more conventionally done. True or false True. >If the bypass cap is necessary would it need to be largish (because the >total cathode impedance is smallish, say <2K) If memory serves me right then the impedance seen when looking into the cathode is (Rp+Ra)/(mu+1). The size of bypass cap needed will a bit less then in a conventional cathode biased stage but not by much so. I hope the AA-batteries you mentioned in your schematic consists of NiCd cells. Normal batteries will blow up! Regards Manfred - ------------------ Manfred Huber MHuber@t-online.de - ------------------ ========================================================================= From: dslagle@earthlink.net (dave slagle) Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions Date: Fri, 3 Nov 2000 13:31:43 -0500 Source: Sound Digest Archive v02.n721 hey j, what happens if one of the tubes is not matched in current draw to the other? in otherwords, if the 10 is running 30ma and the 6c45 is biased to run 35ma??? or take it the other way and let the 10 run 35ma and the russkie only lets 30ma go through... well we know both tubes will have the same current, the question becomes is that how much current they would be running if the other tube were not there? its an interesting question, what happens to a tube when you force it away from its characteristics? can this be done... i bet a small say 300 ohm or so pot in series with the choke will let you tune the sound and nail the operating point... and a 500 ohm DCR choke is easy enough to source for this... otherwise you got 6500 turns of #35 on an EI87 nickel core.... in any event at some point one of the tubes is gonna current limit the other... i would be interested to hear what the tone "pot" does to the sound... and who knows... maybe it will all just fall perfectly into place... tubes have a funny way of doing that. dave >> >> >> B+ >> | >> C|C---> >> C|C >> C|C---> >> | >> 10 _|_ >> ...-----+ >> /^\ | >> | | | >> UUU | >> bypass?----* | (* = center tap of filament >> < | transformer) >> DCR < | >> of this < | >> R and | | >> choke C| | >> totals C| | >> ~860 C| | >> +------+ >> 6C45Pi _|_ >>-----+-----... >> C| --, >> C| | >> C| _|_ >> C| - >> | | 2 x AA battery >> V _|_ >> - >> | >> V >> >> ========================================================================= From: Paul Joppa Subject: Re: [JN] 10 monkeys eat a free lunch - design idea/questions Date: Fri, 03 Nov 2000 17:41:03 -0800 Source: Sound Digest Archive v02.n721 > From: "Epstein, Jeremy" > Design idea: > > Monkey amp using 10 tube driven by 6C45Pi. Both run at 35mA, so no need for > a seperate cathode resistor from the cathode of the 10 to ground: all the > 10's juice flows through the driver tube. > > Design questions: > > Does there need to be a bypass cap from the cathode of the 10 to prevent > regeneration? As long as the output signal current goes through the cathode circuit to ground (then through the power supply back to the output transformer and tube), it needs to be bypassed. With parallel feed or ultrapath, the signal current in the midband can be kept out of the cathode to ground path and the bypass cap is not needed. I have talked briefly with two people who have tried parafeed with and without the cathode bypass cap; both thought it sounded better (had better bass) with the cap. It might have worked better if the parafeed/ultrapath cap were as large as a bypass cap, like 220uF instead of 2.2uF. I have not heard from anyone who has tried this yet though - I say, go for it, Jeremy! and tell us what happened... Another way to look at it - without a bypass it is a mu follower of the amplified choke variety (an SRPP with a choke for the upper bias resistor). This is a great driver circuit, with output taken from the lower plate. Or, take it from the upper cathode as a cathode follower output, cap coupled to an interleaved output transformer. Kind of a mutant spud... > If the bypass cap is necessary would it need to be largish (because the > total cathode impedance is smallish, say <2K) or small (because there is in > fact a "times mu" term that makes the effective impedance large)? Like any other cathode bypass cap, it should be large enough to have a small impedance relative to the rest of the output signal current loop. In addition, if the cathode impedance is to be kept small enough to not affect the 10's operation, the cathode impedance should be small relative to the 10's cathode impedance which is on the order of 1/gm. > Note that this could be built as a one-resistor per channel amp (grid > stopper on 6C45pi), if a battery is used to bias the driver and the plate > choke DCR is made 860 ohms, and a grid choke is used on the input. So use a ferrite bead on that grid! :^) - -Paul Joppa ========================================================================= From: Rich Conte Subject: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7 Date: Fri, 09 Feb 2001 21:24:41 -0500 Source: Sound Digest Archive v02.n802 Dear Folks, I just installed 2 - 10's running only 6.3 V AC Filament supply v. req. 7.5 and do they ever sound good, just DC coupled via 6SN7's, rectifier is GZ37 and outputs are NOS. Anyone use these, they are the BRIGHTEST filaments I've seen, look like Svetlana Triodes. The tubes GE VT25 and RCA VT25...even at 5.0 V AC they are wonderful. The plates run about 305VDC and current about 20mA. Cheers,. ========================================================================= From: SBench@aol.com Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7 Date: Fri, 9 Feb 2001 21:46:59 EST Source: Sound Digest Archive v02.n803 In a message dated 01-02-09 21:28:51 EST, rconte@attglobal.net writes: > I just installed 2 - 10's running only 6.3 V AC Filament supply v. req. > 7.5 and do they ever sound good, just DC coupled > via 6SN7's, rectifier is GZ37 and outputs are NOS. > > Anyone use these, they are the BRIGHTEST filaments I've seen, look like > Svetlana Triodes. > > The tubes GE VT25 and RCA VT25...even at 5.0 V AC they are wonderful. > > The plates run about 305VDC and current about 20mA. > I can confirm that 801s (which oughta be similar) sound great at that operating point (300V, 20mA and 6.3V on the filaments). - -Steve ========================================================================= From: evaguido Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7 Date: Sat, 10 Feb 2001 12:49:30 +0100 Source: Sound Digest Archive v02.n803 Guys Arent these tubes supposed to run on 7.5 V ? lowering heater voltage will decrease life expectancy...... Enjoy your sound (a little longer :-) Guido At 21:46 9-2-01 -0500, SBench@aol.com wrote: >In a message dated 01-02-09 21:28:51 EST, rconte@attglobal.net writes: > >> I just installed 2 - 10's running only 6.3 V AC Filament supply v. req. >> 7.5 and do they ever sound good, just DC coupled >> via 6SN7's, rectifier is GZ37 and outputs are NOS. >> >> Anyone use these, they are the BRIGHTEST filaments I've seen, look like >> Svetlana Triodes. >> >> The tubes GE VT25 and RCA VT25...even at 5.0 V AC they are wonderful. >> >> The plates run about 305VDC and current about 20mA. >> > >I can confirm that 801s (which oughta be similar) sound great at >that operating point (300V, 20mA and 6.3V on the filaments). > >-Steve ========================================================================= From: SBench@aol.com Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7 Date: Sat, 10 Feb 2001 20:16:46 EST Source: Sound Digest Archive v02.n803 In a message dated 01-02-10 06:46:26 EST, EvaGuido@iaehv.nl writes: > Guys > > Arent these tubes supposed to run on 7.5 V ? > > lowering heater voltage will decrease life expectancy...... > > Enjoy your sound (a little longer :-) > Hi, DHT W-Th filaments when run starved can be regenerated to a large extent. Procedure is in RCA TT3 among other places. Note that the operating point chosen is very low with respect to the tubes capability (6 watts and only 20mA). When running close to the tubes rated capabilities, starving the filament will indeed lead to (temporarily) reduced life. With oxide coated devices, the tube cannot successfully be resuscitated so beware of using that technique on oxide devices (2A3, 300B etc). Thanks for the cautionary note. Best Regards, Steve ========================================================================= From: evaguido Subject: Re: [JN] 10 Tube, VT25 DC Coupled driven by 6sn7 Date: Sun, 11 Feb 2001 22:28:19 +0100 Source: Sound Digest Archive v02.n804 Hi all Steve wrote: >DHT W-Th filaments when run starved can be regenerated to a large >extent. Procedure is in RCA TT3 among other places. I'll give that a look >Note that the >operating point chosen is very low with respect to the tubes capability >(6 watts and only 20mA). Yes > When running close to the tubes rated >capabilities, starving the filament will indeed lead to (temporarily) reduced >life. With oxide coated devices, the tube cannot successfully be >resuscitated so beware of using that technique on oxide devices >(2A3, 300B etc). Yes, that is true, however regenerating needs extreme care as the tube may die as well, if not regnerated the right way (but what can you loose....) >Thanks for the cautionary note. thanks ! Guido >Best Regards, >Steve ========================================================================= From: Allen Wright Subject: [JN] Re: 10 turn ww pots Date: Sat, 13 Feb 1999 08:42:30 -0500 Source: Sound Digest Archive v02.n044 Various people contributed: >>>> I believe the ten-turns do not sound OK, though I did not listen to them........Crack one open and you will see very quickly why. They are made with a VERY long spirial element. Very high inductance<<< Gents, this is all opinion. Has anyone actually taken a listen? Allen (VSE) ========================================================================= From: Grover Gardner Subject: Re: [JN] Re: 10 turn ww pots Date: Sat, 13 Feb 1999 22:03:46 -0500 Source: Sound Digest Archive v02.n044 At 8:42 AM -0500 2/13/99, Allen Wright wrote: >Various people contributed: > >>>>> I believe the ten-turns do not sound OK, though I did not listen to >them........Crack one open and you will see very quickly why. They are made >with a VERY long spirial element. Very high inductance<<< > >Gents, this is all opinion. Has anyone actually taken a listen? > >Allen (VSE) 10 turn pots can be very noisy and unsatisfactory sonically, if used directly in the input path. Grover Gardner groverg@postoffice.att.net ========================================================================= From: "PEARL Cust Serv" Subject: Re: [JN] Re: 10 turn ww pots Date: Sat, 13 Feb 1999 22:36:57 -0700 Source: Sound Digest Archive v02.n044 >From: Grover Gardner >To: Allen Wright , JoeNet >Subject: Re: [JN] Re: 10 turn ww pots >Date: Sat, Feb 13, 1999, 8:03 PM > > At 8:42 AM -0500 2/13/99, Allen Wright wrote: >>Various people contributed: >> >>>>>> I believe the ten-turns do not sound OK, though I did not listen to >>them........Crack one open and you will see very quickly why. They are made >>with a VERY long spirial element. Very high inductance<<< >> >>Gents, this is all opinion. Has anyone actually taken a listen? >> >>Allen (VSE) > > 10 turn pots can be very noisy and unsatisfactory sonically, if used > directly in the input path. > > Grover Gardner > groverg@postoffice.att.net - -------------------- I was hoping against hope. Steppers are SUCH a PITA!! Bill - PEARL ========================================================================= From: evaguido Subject: Re: [JN] Re: 10 turn ww pots Date: Sun, 14 Feb 1999 22:46:41 +0100 Source: Sound Digest Archive v02.n044 At 08:42 13-2-99 -0500, Allen Wright wrote: >Various people contributed: > >>>>> I believe the ten-turns do not sound OK, though I did not listen to >them........Crack one open and you will see very quickly why. They are made >with a VERY long spirial element. Very high inductance<<< > >Gents, this is all opinion. Has anyone actually taken a listen? I suppose... As I wrote, the series inductance might be a burden, but it depends on the loading impedance The proof is in the eating of the pudding. I guess at least I have to buy a pair Which brand is reccomended ? Guido >Allen (VSE) > > ========================================================================= From: Torsten.Loesch@enhar-ha.nthames.nhs.uk Subject: Re: [JN] Re: 10 turn ww pots Date: 15 Feb 1999 11:30:35 +0000 Source: Sound Digest Archive v02.n044 Hi there, > >>>> I believe the ten-turns do not sound OK, though I did not listen to > them........Crack one open and you will see very quickly why. They are made > with a VERY long spirial element. Very high inductance<<< > > Gents, this is all opinion. Has anyone actually taken a listen? I did. While still doing solid Stae. I did not like the sound much. Though due to low capacitances there was not much rolloff.... I still think that the only way is a stepped (ladder) attenuator. Cermet pots are close but wear out quickly and often have tracking problems.... Later Thorsten ========================================================================= From: SBench@aol.com Subject: [JN] 10W SE No R No C Amp Date: Sun, 24 Dec 2000 00:56:12 EST Source: Sound Digest Archive v02.n769 Hi All, Finally had a bit of time to update my web page. I put up an 845 amp providing about 10 watts using only tubes, transformers and inductors. Driver stage is differential 6DJ8 (push pull class A driver) driving SE 845. Interestingly, provides some insight into how power systems affect the sound quality! During development I was able to find topologies producing graininess (traced to limited slew rate at HF, even though frequency response MEASURED OK) and classic old style "distorted tube" sound (related to signal frequency ripple). Direct access via http://members.aol.com/sbench/norc845.html or by the front door at http://members.aol.com/sbench101 Best of seasons greetings to all. Steve ========================================================================= From: Grover Gardner Subject: Re: [JN] 10Y (VT-25) vs 801A Date: Thu, 12 Aug 1999 11:38:23 -0400 Source: Sound Digest Archive v02.n240 I have been exploring this myself. I would assume the 801 is built to allow more grid current. I know the plate and grid structures are different, the 801 having a boxer, deeper plate. I haven't yet been able to compare the sound of the two. jsuen wrote: > > Hello, > > I would like to know if there is any significant difference between 10Y > and 801A apart from higher voltage and power ratings of the latter. - -- Grover Gardner groverg@postoffice.att.net ========================================================================= From: jsuen Subject: [JN] 10Y (VT-25) vs 801A Date: Thu, 12 Aug 1999 19:25:33 +0800 Source: Sound Digest Archive v02.n240 Hello, I would like to know if there is any significant difference between 10Y and 801A apart from higher voltage and power ratings of the latter. ========================================================================= From: Carter Hendricks Subject: [JN] 112A/12A Date: Wed, 28 Mar 2001 22:48:01 -0600 Source: Sound Digest Archive v02.n847 Does anyone have 4 of these new/used for purchase or trade??? --Carter ========================================================================= From: "Danielak, Robert M" Subject: [JN] RE: 112 pre with battery filaments Date: Wed, 06 Dec 2000 17:20:57 -0500 Source: Sound Digest Archive v02.n754 hi folks, where shall i start? ok Q1: should you charge while playing audio? probably not. as the bear mentioned below, it sorta defeats the purpose of battery filaments. now nicads are known for their very low impedance, and some folks go on to suggest that they make good "ripple-filters". but they do have significant impedance at higher frequencies. the go inductive starting above 100Hz to 1kHz. Q2: should you use ni-cads or lead-acid? memory effect is almost a joke in the industry, these days. most battery engineers consider it an "urban-legend". most capacity loss in nicad packs is done by heavy discharge to very low states of charge - i.e. running the batteries flat. in a series pack of 4 or six cells, oftentimes one or more of these cells (weakest) are forced into reversal (negative voltage). this causes premature degradation which some folks attribute to "memory-effect". overcharging has a similar effect... now for this application, what is the best choice? 5V @ 0.25A means that you need 4 ni-cads in series (~4.8V). but the voltage profile if fairly flat. a D-cell is anywhere between 4 to 5 Ah. so theoretically, you can get 16-20 hours out of them. self-discharge is quite high for ni-cads though. you might want to keep them on a trickle-charge once they're topped up. C/50, or about 100mA is a good rate. the charger could be as simple as a constant current source switchable between a *fast* rate and a *trickle* rate, or just a single *low* rate for overnight (8-10 hour charging). you could expect that most of the time, you won't discharge to zero capacity, so a C/20 rate might be a good compromise. sealed-lead-acid (SLA) is a fine option, too. they won't give you as many cycles as nicad. but they are a little easier to charge. you can build a simple float charger for them using a dc power supply and a resistor. they are bulki er than nicads, but we're talking tubes, not cell-phones. 3 in series will give you 6V or so. paralleling cells with either of these battery types (especially nicad) is not recommended. if you need more capacity, get a bigger cell. a separate charger circuit is recommended for each battery. the circuits should be fairly simple, and easy to replicate. we're not talking about more than 1A, so a simple LM317 current source should be sufficient. 3. switch network i'd recommend a spdt (or DPDT if you want to isolate the grounds, too) for each battery/filament. in one position you connect the battery to the filaments, in the other position to the charger. if you are using cathode bias, i suppose you need a DPDT switch. if you need any detailed help, just let me know... hth, bob.d. > ---------- > From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com] > Sent: Wednesday, December 06, 2000 3:19 PM > To: Joe List > Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500 > > Phil Sieg: > > > > Joes, > > > > I have the kernel of an idea bubbling in my bonnet and have some questions > > for those who have gone before. I am working on a design for a phono and > > line preamp that uses CX-112As in each stage. The stages will be > > IT-coupled > > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp design at > > Direct Heating for the general concept). > > Mighty interesting... > > > > > The 112As seem a good candidate for battery filament supplies. > > Yes, it indeed does, and this is nothing new. It was designed for battery > operation. > > > > And here > > lies my question. I want to use rechargeable NiCad battery packs in > > parallel with switching to recharge as needed (I hope I'm being > > clear). I've > > read Jim de Kort's excellent treatment of the subject on his site (and > > that's a way cool thing you are doing, Jim) but need a little > > more detail to > > implement.> > > I'm slightly involved in this project and have myself a UX-226 linestage > with battery operated filaments. Jim and I have had a lot of conversation > about how to charge this babies. Now, I don't quite see why you would want > to use NiCads. They have a most annoying memory effect. Unless you want to > keep your tubes on until the batteries are virtually drained every time you > will not have a relaxed relationship with these batteries for long. They > WILL annoy you... Use lead batteries - these may be more expensive, but they > last much longer and are much easier to use. If batteries in series are > needed for an application, parallelling them when charging is definately the > best and easiest option for a good recharge. > > > > I will use the standard power transformer/valve rectifier for the > > B+. But I > > would like to design a battery-based supply that recharges while > > in use. So > > I'm looking for help and input from those who have implemented > > these things. > > The 12A has 5V, 0.25A filaments. > > As I said, I have done this with my 26's. No problems so far AT all. I use 2 > ea 2V 8Ah lead cells in parallel per filament (with drop resistors of > course). I wouldn't want to charge the supply while in use - you loose > almost all the benefits of the battery approach... > > regards, > Bjørn Aaholm > > http://listen.to/aaholm (Read about my UX-226 linestage here if you want to > know more) > > ========================================================================= From: "Phil Sieg" Subject: Re: [JN] RE: 112 pre with battery filaments Date: Wed, 6 Dec 2000 18:50:50 -0500 Source: Sound Digest Archive v02.n754 Bjorn, Bob: many thanks for your detailed replies. Did a little more research today (and talked at length with a local DIY friend whose an electronics instructor at the local Tech Institute). Seems lead acid is the way to go. Here's the current plan (no pun intended). I will use 6V rechargeable lead-acid batteries, one per tube. The positive leg will be fitted with a dropping resistor; the negative with a 120VAC DPDT relay that will be activated when the rectifier filament supply is turned on After greater perusal of Jim's site (and increasing appreciation for what he's doing ), I plan to build a charger per channel that put out 18V with the batteries in series. It will be switchable separately from the main PS. The batteries I'm looking at are rated for 1.3Ah for 20 Hr, which means at a draw of 250 mA, they should last a long time. A *long* listening session for me is 6-7 hours, and that's only reached usually when we have our monthly DIY get together. So I can't see the need for parallel batteries and a switching supply. So feasible/ Phil - ----- Original Message ----- From: "Danielak, Robert M" To: "Joe List" Sent: Wednesday, 06 December, 2000 17.20 Subject: [JN] RE: 112 pre with battery filaments > hi folks, > > where shall i start? > > ok > > Q1: should you charge while playing audio? > > probably not. > as the bear mentioned below, it sorta defeats the purpose of > battery filaments. > > now nicads are known for their very low impedance, and some > folks go on to suggest that they make good "ripple-filters". > > but they do have significant impedance at higher frequencies. > the go inductive starting above 100Hz to 1kHz. > > Q2: should you use ni-cads or lead-acid? > > memory effect is almost a joke in the industry, these days. > most battery engineers consider it an "urban-legend". > > most capacity loss in nicad packs is done by heavy discharge > to very low states of charge - i.e. running the batteries flat. > > in a series pack of 4 or six cells, oftentimes one or more of these cells (weakest) are forced into reversal (negative voltage). > this causes premature degradation which some folks attribute to "memory-effect". > > overcharging has a similar effect... > > now for this application, what is the best choice? > > 5V @ 0.25A means that you need 4 ni-cads in series (~4.8V). > but the voltage profile if fairly flat. > > a D-cell is anywhere between 4 to 5 Ah. > so theoretically, you can get 16-20 hours out of them. > > self-discharge is quite high for ni-cads though. > > you might want to keep them on a trickle-charge once they're > topped up. C/50, or about 100mA is a good rate. > > the charger could be as simple as a constant current source > switchable between a *fast* rate and a *trickle* rate, > or just a single *low* rate for overnight (8-10 hour charging). > > you could expect that most of the time, you won't discharge to > zero capacity, so a C/20 rate might be a good compromise. > > sealed-lead-acid (SLA) is a fine option, too. > they won't give you as many cycles as nicad. but they are a little easier to charge. > you can build a simple float charger for them using a dc power supply and a resistor. they are bulkier than nicads, but we're talking > tubes, not cell-phones. > 3 in series will give you 6V or so. > > paralleling cells with either of these battery types (especially nicad) is not recommended. > if you need more capacity, get a bigger cell. > > a separate charger circuit is recommended for each battery. > > the circuits should be fairly simple, and easy to replicate. > we're not talking about more than 1A, so a simple LM317 current > source should be sufficient. > > 3. switch network > > i'd recommend a spdt (or DPDT if you want to isolate the grounds, too) > for each battery/filament. in one position you connect the battery > to the filaments, in the other position to the charger. > > if you are using cathode bias, i suppose you need a DPDT switch. > > if you need any detailed help, just let me know... > > hth, > > bob.d. > > > ---------- > > From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com] > > Sent: Wednesday, December 06, 2000 3:19 PM > > To: Joe List > > Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500 > > > > Phil Sieg: > > > > > > Joes, > > > > > > I have the kernel of an idea bubbling in my bonnet and have some questions > > > for those who have gone before. I am working on a design for a phono and > > > line preamp that uses CX-112As in each stage. The stages will be > > > IT-coupled > > > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp design at > > > Direct Heating for the general concept). > > > > Mighty interesting... > > > > > > > > > The 112As seem a good candidate for battery filament supplies. > > > > Yes, it indeed does, and this is nothing new. It was designed for battery > > operation. > > > > > > > And here > > > lies my question. I want to use rechargeable NiCad battery packs in > > > parallel with switching to recharge as needed (I hope I'm being > > > clear). I've > > > read Jim de Kort's excellent treatment of the subject on his site (and > > > that's a way cool thing you are doing, Jim) but need a little > > > more detail to > > > implement.> > > > > I'm slightly involved in this project and have myself a UX-226 linestage > > with battery operated filaments. Jim and I have had a lot of conversation > > about how to charge this babies. Now, I don't quite see why you would want > > to use NiCads. They have a most annoying memory effect. Unless you want to > > keep your tubes on until the batteries are virtually drained every time you > > will not have a relaxed relationship with these batteries for long. They > > WILL annoy you... Use lead batteries - these may be more expensive, but they > > last much longer and are much easier to use. If batteries in series are > > needed for an application, parallelling them when charging is definately the > > best and easiest option for a good recharge. > > > > > > > I will use the standard power transformer/valve rectifier for the > > > B+. But I > > > would like to design a battery-based supply that recharges while > > > in use. So > > > I'm looking for help and input from those who have implemented > > > these things. > > > The 12A has 5V, 0.25A filaments. > > > > As I said, I have done this with my 26's. No problems so far AT all. I use 2 > > ea 2V 8Ah lead cells in parallel per filament (with drop resistors of > > course). I wouldn't want to charge the supply while in use - you loose > > almost all the benefits of the battery approach... > > > > regards, > > Bjørn Aaholm > > > > http://listen.to/aaholm (Read about my UX-226 linestage here if you want to > > know more) > > > > > ========================================================================= From: "Danielak, Robert M" Subject: RE: [JN] RE: 112 pre with battery filaments Date: Wed, 06 Dec 2000 19:07:33 -0500 Source: Sound Digest Archive v02.n754 minor correction phil: the rating of 1.3AH @ 20hours is simply describing how they measured the capacity (they used a C/20 rate). they specify the 20-hour rate because it gives them a better #. if you used a 2 hour rate (C/2) you would wind up with less capacity (because of voltage performance). so you have to stick with the 1.3AH number as a starting point. this means that you will be able to operate for 1.3AH / 0.25A = 5.2 hours, maximum. in other words, you're using more like a c/5 discharge rate. so the capacity will be a little less, and you'll get less run-time. probably no more than 5 hours. and when they get near flat, they will drop like a rock (and potentially cause degradation). if you use a bigger battery, you will get the potential for longer run-time, and you'll be going easier on the cells during the one or two hour sessions. this means you will get more cycles out of them. also, unless you have a compelling reason to charge the packs in series, i'd suggest doing a 6V char ger per battery. it's much easier to manage if there are slight differences from battery to battery. in series, you are forcing the same charge into each battery. if one reaches ful l charge first, it will be overcharged, while the others catch up. this will shorten cycle life... a separate charger, with proper charge termination can extend the life of the batteries, significant ly. you should be able to get 500 full cycles from a modern battery. more if you treat them well (no overcharge, overdischarge/reversal). less if you abuse them. good luck, bob.d. ps: go for the battery B+ supply, too!!!! > ---------- > From: Phil Sieg[SMTP:psieg@nxs.net] > Sent: Wednesday, December 06, 2000 6:50 PM > To: Danielak, Robert M; Joe List > Subject: Re: [JN] RE: 112 pre with battery filaments > > Bjorn, Bob: > > many thanks for your detailed replies. Did a little more research today > (and talked at length with a local DIY friend whose an electronics > instructor at the local Tech Institute). Seems lead acid is the way to go. > > Here's the current plan (no pun intended). I will use 6V rechargeable > lead-acid batteries, one per tube. The positive leg will be fitted with a > dropping resistor; the negative with a 120VAC DPDT relay that will be > activated when the rectifier filament supply is turned on > > After greater perusal of Jim's site (and increasing appreciation for what > he's doing ), I plan to build a charger per channel that put out 18V with > the batteries in series. It will be switchable separately from the main PS. > The batteries I'm looking at are rated for 1.3Ah for 20 Hr, which means at a > draw of 250 mA, they should last a long time. A *long* listening session > for me is 6-7 hours, and that's only reached usually when we have our > monthly DIY get together. So I can't see the need for parallel batteries > and a switching supply. > > So feasible/ > > Phil > > > ----- Original Message ----- > From: "Danielak, Robert M" > To: "Joe List" > Sent: Wednesday, 06 December, 2000 17.20 > Subject: [JN] RE: 112 pre with battery filaments > > > > hi folks, > > > > where shall i start? > > > > ok > > > > Q1: should you charge while playing audio? > > > > probably not. > > as the bear mentioned below, it sorta defeats the purpose of > > battery filaments. > > > > now nicads are known for their very low impedance, and some > > folks go on to suggest that they make good "ripple-filters". > > > > but they do have significant impedance at higher frequencies. > > the go inductive starting above 100Hz to 1kHz. > > > > Q2: should you use ni-cads or lead-acid? > > > > memory effect is almost a joke in the industry, these days. > > most battery engineers consider it an "urban-legend". > > > > most capacity loss in nicad packs is done by heavy discharge> > > to very low states of charge - i.e. running the batteries flat. > > > > in a series pack of 4 or six cells, oftentimes one or more of these cells > (weakest) are forced into reversal (negative voltage). > > this causes premature degradation which some folks attribute to > "memory-effect". > > > > overcharging has a similar effect... > > > > now for this application, what is the best choice? > > > > 5V @ 0.25A means that you need 4 ni-cads in series (~4.8V). > > but the voltage profile if fairly flat. > > > > a D-cell is anywhere between 4 to 5 Ah. > > so theoretically, you can get 16-20 hours out of them. > > > > self-discharge is quite high for ni-cads though. > > > > you might want to keep them on a trickle-charge once they're > > topped up. C/50, or about 100mA is a good rate. > > > > the charger could be as simple as a constant current source > > switchable between a *fast* rate and a *trickle* rate, > > or just a single *low* rate for overnight (8-10 hour charging). > > > > you could expect that most of the time, you won't discharge to > > zero capacity, so a C/20 rate might be a good compromise. > > > > sealed-lead-acid (SLA) is a fine option, too. > > they won't give you as many cycles as nicad. but they are a little easier > to charge. > > you can build a simple float charger for them using a dc power supply and > a resistor. they are bulkier than nicads, but we're talking > > tubes, not cell-phones. > > 3 in series will give you 6V or so. > > > > paralleling cells with either of these battery types (especially nicad) is > not recommended. > > if you need more capacity, get a bigger cell. > > > > a separate charger circuit is recommended for each battery. > > > > the circuits should be fairly simple, and easy to replicate. > > we're not talking about more than 1A, so a simple LM317 current > > source should be sufficient. > > > > 3. switch network > > > > i'd recommend a spdt (or DPDT if you want to isolate the grounds, too) > > for each battery/filament. in one position you connect the battery > > to the filaments, in the other position to the charger. > > > > if you are using cathode bias, i suppose you need a DPDT switch. > > > > if you need any detailed help, just let me know... > > > > hth, > > > > bob.d. > > > > > ---------- > > > From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com] > > > Sent: Wednesday, December 06, 2000 3:19 PM > > > To: Joe List > > > Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500 > > > > > > Phil Sieg: > > > > > > > > Joes, > > > > > > > > I have the kernel of an idea bubbling in my bonnet and have some > questions > > > > for those who have gone before. I am working on a design for a phono > and > > > > line preamp that uses CX-112As in each stage. The stages will be > > > > IT-coupled > > > > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp design > at > > > > Direct Heating for the general concept). > > > > > > Mighty interesting... > > > > > > > > > > > > > The 112As seem a good candidate for battery filament supplies. > > > > > > Yes, it indeed does, and this is nothing new. It was designed for > battery > > > operation. > > > > > > > > > > And here > > > > lies my question. I want to use rechargeable NiCad battery packs in > > > > parallel with switching to recharge as needed (I hope I'm being > > > > clear). I've > > > > read Jim de Kort's excellent treatment of the subject on his site (and > > > > that's a way cool thing you are doing, Jim) but need a little > > > > more detail to > > > > implement.> > > > > > > I'm slightly involved in this project and have myself a UX-226 linestage > > > with battery operated filaments. Jim and I have had a lot of > conversation > > > about how to charge this babies. Now, I don't quite see why you would > want > > > to use NiCads. They have a most annoying memory effect. Unless you want > to > > > keep your tubes on until the batteries are virtually drained every time > you > > > will not have a relaxed relationship with these batteries for long. They> > > > WILL annoy you... Use lead batteries - these may be more expensive, but > they > > > last much longer and are much easier to use. If batteries in series are > > > needed for an application, parallelling them when charging is definately > the > > > best and easiest option for a good recharge. > > > > > > > > > > I will use the standard power transformer/valve rectifier for the > > > > B+. But I > > > > would like to design a battery-based supply that recharges while > > > > in use. So > > > > I'm looking for help and input from those who have implemented > > > > these things. > > > > The 12A has 5V, 0.25A filaments. > > > > > > As I said, I have done this with my 26's. No problems so far AT all. I > use 2 > > > ea 2V 8Ah lead cells in parallel per filament (with drop resistors of > > > course). I wouldn't want to charge the supply while in use - you loose > > > almost all the benefits of the battery approach... > > > > > > regards, > > > Bjørn Aaholm > > > > > > http://listen.to/aaholm (Read about my UX-226 linestage here if you want > to > > > know more) > > > > > > > > > > ========================================================================= From: "Phil Sieg" Subject: Re: [JN] RE: 112 pre with battery filaments Date: Wed, 6 Dec 2000 20:05:26 -0500 Source: Sound Digest Archive v02.n754 Bob, Thanks for the corrections. Panasonic has a lead-acid battery rated at 6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one. WRT the charger, if I can construct a charger for each channel that can feed 6V to each battery in parallel with the ability to provide at least 2A of current draw, won't that work as well as separate chargers? As far as battery B+ goes, let me get the SO used to battery filament supplies ;-). The idea of 25 12V batteries in series for each channel [3 amplifiers per side using 2 x 45 (woofer); 1 x 45 (mid); 1 x 71A (tweet)], plus the preamp is a hard sell to a spouse who has always given me free reign in the audio arena. Phil ----- Original Message ----- From: "Danielak, Robert M" To: "Joe List" Sent: Wednesday, 06 December, 2000 19.07 Subject: RE: [JN] RE: 112 pre with battery filaments > minor correction phil: > > the rating of 1.3AH @ 20hours is simply describing how they measured > the capacity (they used a C/20 rate). > > they specify the 20-hour rate because it gives them a better #. > > if you used a 2 hour rate (C/2) you would wind up with less capacity > (because of voltage performance). > > so you have to stick with the 1.3AH number as a starting point. > > this means that you will be able to operate for 1.3AH / 0.25A = 5.2 hours, maximum. > > in other words, you're using more like a c/5 discharge rate. > so the capacity will be a little less, and you'll get less run-time. > > probably no more than 5 hours. > and when they get near flat, they will drop like a rock > (and potentially cause degradation). > > if you use a bigger battery, you will get the potential for longer > run-time, and you'll be going easier on the cells during the one > or two hour sessions. this means you will get more cycles out of them. > > also, unless you have a compelling reason to charge the packs in series, i'd suggest doing a 6V charger per battery. > > it's much easier to manage if there are slight differences from > battery to battery. in series, you are forcing the same charge into each battery. if one reaches full charge first, it will be overcharged, while the others catch up. this will shorten cycle life... > > a separate charger, with proper charge termination can extend the life of the batteries, significantly. > > you should be able to get 500 full cycles from a modern battery. > more if you treat them well (no overcharge, overdischarge/reversal). > less if you abuse them. > > good luck, > > bob.d. > > ps: go for the battery B+ supply, too!!!! > > ---------- > > From: Phil Sieg[SMTP:psieg@nxs.net] > > Sent: Wednesday, December 06, 2000 6:50 PM > > To: Danielak, Robert M; Joe List > > Subject: Re: [JN] RE: 112 pre with battery filaments > > > > Bjorn, Bob: > > > > many thanks for your detailed replies. Did a little more research today > > (and talked at length with a local DIY friend whose an electronics > > instructor at the local Tech Institute). Seems lead acid is the way to go. > > > > Here's the current plan (no pun intended). I will use 6V rechargeable > > lead-acid batteries, one per tube. The positive leg will be fitted with a > > dropping resistor; the negative with a 120VAC DPDT relay that will be > > activated when the rectifier filament supply is turned on > > > > After greater perusal of Jim's site (and increasing appreciation for what > > he's doing ), I plan to build a charger per channel that put out 18V with > > the batteries in series. It will be switchable separately from the main PS. > > The batteries I'm looking at are rated for 1.3Ah for 20 Hr, which means at a > > draw of 250 mA, they should last a long time. A *long* listening session > > for me is 6-7 hours, and that's only reached usually when we have our > > monthly DIY get together. So I can't see the need for parallel batteries > > and a switching supply. > > > > So feasible/ > > > > Phil > > > > > > ----- Original Message ----- > > From: "Danielak, Robert M" > > To: "Joe List" > > Sent: Wednesday, 06 December, 2000 17.20 > > Subject: [JN] RE: 112 pre with battery filaments > > > > > > > hi folks, > > > > > > where shall i start? > > > > > > ok > > > > > > Q1: should you charge while playing audio? > > > > > > probably not. > > > as the bear mentioned below, it sorta defeats the purpose of > > > battery filaments. > > > > > > now nicads are known for their very low impedance, and some > > > folks go on to suggest that they make good "ripple-filters". > > > > > > but they do have significant impedance at higher frequencies. > > > the go inductive starting above 100Hz to 1kHz. > > > > > > Q2: should you use ni-cads or lead-acid? > > > > > > memory effect is almost a joke in the industry, these days. > > > most battery engineers consider it an "urban-legend". > > > > > > most capacity loss in nicad packs is done by heavy discharge> > > > to very low states of charge - i.e. running the batteries flat. > > > > > > in a series pack of 4 or six cells, oftentimes one or more of these cells > > (weakest) are forced into reversal (negative voltage). > > > this causes premature degradation which some folks attribute to > > "memory-effect". > > > > > > overcharging has a similar effect... > > > > > > now for this application, what is the best choice? > > > > > > 5V @ 0.25A means that you need 4 ni-cads in series (~4.8V). > > > but the voltage profile if fairly flat. > > > > > > a D-cell is anywhere between 4 to 5 Ah. > > > so theoretically, you can get 16-20 hours out of them. > > > > > > self-discharge is quite high for ni-cads though. > > > > > > you might want to keep them on a trickle-charge once they're > > > topped up. C/50, or about 100mA is a good rate. > > > > > > the charger could be as simple as a constant current source > > > switchable between a *fast* rate and a *trickle* rate, > > > or just a single *low* rate for overnight (8-10 hour charging). > > > > > > you could expect that most of the time, you won't discharge to > > > zero capacity, so a C/20 rate might be a good compromise. > > > > > > sealed-lead-acid (SLA) is a fine option, too. > > > they won't give you as many cycles as nicad. but they are a little easier > > to charge. > > > you can build a simple float charger for them using a dc power supply and > > a resistor. they are bulkier than nicads, but we're talking > > > tubes, not cell-phones. > > > 3 in series will give you 6V or so. > > > > > > paralleling cells with either of these battery types (especially nicad) is > > not recommended. > > > if you need more capacity, get a bigger cell. > > > > > > a separate charger circuit is recommended for each battery. > > > > > > the circuits should be fairly simple, and easy to replicate. > > > we're not talking about more than 1A, so a simple LM317 current > > > source should be sufficient. > > > > > > 3. switch network > > > > > > i'd recommend a spdt (or DPDT if you want to isolate the grounds, too) > > > for each battery/filament. in one position you connect the battery > > > to the filaments, in the other position to the charger. > > > > > > if you are using cathode bias, i suppose you need a DPDT switch. > > > > > > if you need any detailed help, just let me know... > > > > > > hth, > > > > > > bob.d. > > > > > > > ---------- > > > > From: Bj> ørn Aaholm[SMTP:bjorn@vt52.com] > > > > Sent: Wednesday, December 06, 2000 3:19 PM > > > > To: Joe List > > > > Subject: SV: [JN] Date: Tue, 5 Dec 2000 18:57:09 -0500 > > > > > > > > Phil Sieg: > > > > > > > > > > Joes, > > > > > > > > > > I have the kernel of an idea bubbling in my bonnet and have some > > questions > > > > > for those who have gone before. I am working on a design for a phono > > and > > > > > line preamp that uses CX-112As in each stage. The stages will be > > > > > IT-coupled > > > > > (Sakuma-style, see his 12A/12A/12A/12A/50 phono pre/power amp design > > at > > > > > Direct Heating for the general concept). > > > > > > > > Mighty interesting... > > > > > > > > > > > > > > > > > The 112As seem a good candidate for battery filament supplies. > > > > > > > > Yes, it indeed does, and this is nothing new. It was designed for > > battery > > > > operation. > > > > > > > > > > > > > And here > > > > > lies my question. I want to use rechargeable NiCad battery packs in > > > > > parallel with switching to recharge as needed (I hope I'm being > > > > > clear). I've > > > > > read Jim de Kort's excellent treatment of the subject on his site (and > > > > > that's a way cool thing you are doing, Jim) but need a little > > > > > more detail to > > > > > implement.> > > > > > > > > I'm slightly involved in this project and have myself a UX-226 linestage > > > > with battery operated filaments. Jim and I have had a lot of > > conversation > > > > about how to charge this babies. Now, I don't quite see why you would > > want > > > > to use NiCads. They have a most annoying memory effect. Unless you want > > to > > > > keep your tubes on until the batteries are virtually drained every time > > you > > > > will not have a relaxed relationship with these batteries for long. They> > > > > WILL annoy you... Use lead batteries - these may be more expensive, but > > they > > > > last much longer and are much easier to use. If batteries in series are > > > > needed for an application, parallelling them when charging is definately > > the > > > > best and easiest option for a good recharge. > > > > > > > > > > > > > I will use the standard power transformer/valve rectifier for the > > > > > B+. But I > > > > > would like to design a battery-based supply that recharges while > > > > > in use. So > > > > > I'm looking for help and input from those who have implemented > > > > > these things. > > > > > The 12A has 5V, 0.25A filaments. > > > > > > > > As I said, I have done this with my 26's. No problems so far AT all. I > > use 2 > > > > ea 2V 8Ah lead cells in parallel per filament (with drop resistors of > > > > course). I wouldn't want to charge the supply while in use - you loose > > > > almost all the benefits of the battery approach... > > > > > > > > regards, > > > > Bjørn Aaholm > > > > > > > > http://listen.to/aaholm (Read about my UX-226 linestage here if you want > > to > > > > know more) > > > > > > > > > > > > > > > > ========================================================================= From: Simon Busbridge Subject: Re: [JN] RE: 112 pre with battery filaments Date: Thu, 7 Dec 2000 07:37:30 +0000 (GMT) Source: Sound Digest Archive v02.n754 NiMH? Supposed to be as good as NiCad but without the memory effect. Never used them personally. Simon Simon Busbridge, BSc(Hons) PhD CPhys MInstP School of Engineering University of Brighton Lewes Road Moulsecoomb Brighton BN2 4GJ UNITED KINGDOM Tel: 0044 (0)1273 642542 Fax: 0044 (0)1273 642327/642301 e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com ========================================================================= From: "Danielak, Robert M" Subject: RE: [JN] RE: 112 pre with battery filaments Date: Thu, 07 Dec 2000 10:36:08 -0500 Source: Sound Digest Archive v02.n755 > Bob, > > Thanks for the corrections. Panasonic has a lead-acid battery rated at > 6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one. > yes, this is more like a C/20 rate (actually C/26). so you don't really need to make adjustments to available capacity based upon discharge rate. 6.5AH / .25A = 26 hours. > WRT the charger, if I can construct a charger for each channel that can feed > 6V to each battery in parallel with the ability to provide at least 2A of > current draw, won't that work as well as separate chargers? > you really don't want to charge cells in parallel. this is because you can't guarantee that they will share equally. you can probably build a single DC supply, then use a current source circuit (like a LM317 + resistor) for each battery. this is not too bad, really. > As far as battery B+ goes, let me get the SO used to battery filament > supplies ;-). The idea of 25 12V batteries in series for each channel [3 > amplifiers per side using 2 x 45 (woofer); 1 x 45 (mid); 1 x 71A (tweet)], > plus the preamp is a hard sell to a spouse who has always given me free > reign in the audio arena. > i hear ya. just figured that if you were taking the plunge.... ;) take care, bob.d. ========================================================================= From: "Danielak, Robert M" Subject: RE: [JN] RE: 112 pre with battery filaments Date: Thu, 07 Dec 2000 10:45:58 -0500 Source: Sound Digest Archive v02.n755 NiMH are pretty expensive. besides that, they require a more complicated charger. their main benefits include a bit higher energy density (they're smaller), decent cycle-life, and they're more environmentally friendly. they are very quickly being overtaken in the market by Lithium Ion (Li Ion). i did not suggest Li Ion because the voltage is all wrong (3.7V average), and because they need special charging techniques, as well. also, any commercially available Li ion batteries contain control/safety electronics which would probably defeat the purpose (at least philosophically) of using batteeries on toobs.... bob.d. > ---------- > From: Simon Busbridge[SMTP:S.C.Busbridge@bton.ac.uk] > Sent: Thursday, December 07, 2000 2:37 AM > To: Danielak, Robert M > Cc: Joe List > Subject: Re: [JN] RE: 112 pre with battery filaments > > NiMH? Supposed to be as good as NiCad but without the memory effect. > > Never used them personally. > > Simon > > Simon Busbridge, BSc(Hons) PhD CPhys MInstP > School of Engineering > University of Brighton > Lewes Road > Moulsecoomb > Brighton BN2 4GJ > UNITED KINGDOM > > Tel: 0044 (0)1273 642542 > Fax: 0044 (0)1273 642327/642301 > e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com > > > ========================================================================= From: "Danielak, Robert M" Subject: RE: [JN] RE: 112 pre with battery filaments Date: Thu, 07 Dec 2000 15:16:10 -0500 Source: Sound Digest Archive v02.n755 > ---------- > From: Jim de Kort[SMTP:jim@vt52.com] > Sent: Thursday, December 07, 2000 2:26 PM > To: Danielak, Robert M > Cc: sound@lists.io.com > Subject: RE: [JN] RE: 112 pre with battery filaments > > Hi, > > > > Thanks for the corrections. Panasonic has a lead-acid battery rated at > > > 6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one. > > >yes, this is more like a C/20 rate (actually C/26). > >so you don't really need to make adjustments to available capacity > >based upon discharge rate. > > > >6.5AH / .25A = 26 hours. > jim wrote: > Yes, but it will not be giving 6V anymore and we do not live in a > theoretical world. Take about 70% of that for effective playing time. > sure. i look at it the other way around. he's already mentioned that his max. run time will be less than 8 hours. so this guarantees rather shallow discharge cycles, which SLA batteries prefer. meaning he won't have to replace the batteries in six months.... ;) actually, these batteries will probably give close to the calculated run-time, given the resistive l oading. the voltage performance issue that you are alluding to is more of a concern in constant-power application (the most common applications - feeding a dc-dc converter ...or a motor). > >you really don't want to charge cells in parallel. > >this is because you can't guarantee that they will share equally. > > This is even more so in series. I used to charge my 32 batteries (12V) on a > single lab supply. It takes a while longer to get them all charged, but in > the end they do all fill up the same. This is not to say this is a good way > of charging. Batteries suffer this way as a battery with fuller charge will > pass (full) current to charge another battery that has been drained more. > yeah. we talked about this before... individual chargers are the way to go.... ;) > Best thing to do is use a relay (dual pole, dual contacts) to switch to > it's own little charger. A 317 costs about $1, plus a few resistors and a > transisitor, in all that should cost about $5 for an entire charger. Add > $2-3 for the relay (Siemens has very nice gold-clad silver contact relays) > and you're done. Two of these will not hurt your bank account ;))) > amen... > >you can probably build a single DC supply, then use a current source > >circuit (like a LM317 + resistor) for each battery. > > Voltage source... > right you are. you can simply build a "float-charger". this would be a DC regulated supply set to about 2.2 to 2.3V per cell (6.6 to 6.9V for your 6V battery). it think 6.75V is the recommended float voltage for most manufacturers. check the temperatures on the first few charges. if the batteries are getting too hot, reduce the vo ltage a 10th... would be a good idea to try to implement current limiting of some sort in each circuit. find out the max. rate for that cell. it's probably around 2.5A. > Yes indeed, this is what I do in my chargers. One big > rectifier and capacitor and then split to 8 charger circuits. > > >just figured that if you were taking the plunge.... ;) > > There's an address in the UK (www.steatite.co.uk) that has really cheap > 12V/2Ah batteries ($6-8 each). If you live in the UK this might be a good > oppertunity. I would have done it already, but shipping (even to just > across the channel) is about 4 times that due to weight. > > > > > Regards, > > > Jim de Kort > jim@vt52.com > ========================================================================= From: "Danielak, Robert M" Subject: RE: [JN] RE: 112 pre with battery filaments Date: Thu, 07 Dec 2000 16:15:22 -0500 Source: Sound Digest Archive v02.n755 > >the voltage performance issue that you are alluding to is more > >of a concern in constant-power application (the most common applications - > >feeding a dc-dc converter...or a motor). > > A filament would qualify this description. > interesting... i would have considered it purely resistive. i'll have to think about this.... > >you can simply build a "float-charger". > > That is actually what I have. As long as the power switch is turned off, > the batteries are being charged. The supply is set to 2.3V and current > limited to C/10 by way of two resistors and a transistor. > jim is da' man! just do as he's done ;) > >check the temperatures on the first few charges. if the batteries are > >getting too hot, reduce the voltage a 10th... > > My batteries don't even get luke warm. If they are getting warm then the > current is too high and should be limited. These high currents and > temperatures limit battery life. The amp has all night to recharge, so no > hurry, why push 2A into them when 0.5A will do the job in time for the next > session. > there you go... > >would be a good idea to try to implement current limiting of some sort > >in each circuit. find out the max. rate for that cell. > > Take C/10, it's not the max specification, but it will lengthen tube life > and still recharge before the morning. See my site for a schematic using > the current limiter. > like i said, jim's da' man! take care, bob.d. ========================================================================= From: "Phil Sieg" Subject: Re: [JN] RE: 112 pre with battery filaments Date: Thu, 7 Dec 2000 16:31:49 -0500 Source: Sound Digest Archive v02.n755 Jim, Bob, Thanks again. I think the fog is beginning to clear ;-). Here's what I've come up with, based on your help. One Panasonic 6V, 6.5Ah battery for each tube. (Jim, I am in the US.) A 3-stage version of Tom Ronan's regulator. I have several and can do one per tube. This gives two stages of voltage reg and one of current reg (which is decidedly overkill, but my current preamp now has them on the filament supplies, so my only outlay will be for a few resistors). I have some Hammond filament trannies (12.6V, 2.5A). Put those in the power supply chassis - 1 per channel - rectified and filtered , with a NIWW trim pot to trim the voltage to that required at the inputs of the regulators (I'll need to drop around 5VDC). Feed the regulators from this DC supply in parallel The current reg will be set to allow the battery to draw the 6.75V at 650 MA. Add the relay at the filaments to switch between "charge" and "heat" plus a separate power switch on the charger supply in the PS chassis. Sound right? Have I missed anything? Phil - ----- Original Message ----- From: "Danielak, Robert M" To: Sent: Thursday, 07 December, 2000 15.16 Subject: RE: [JN] RE: 112 pre with battery filaments > > ---------- > > From: Jim de Kort[SMTP:jim@vt52.com] > > Sent: Thursday, December 07, 2000 2:26 PM > > To: Danielak, Robert M > > Cc: sound@lists.io.com > > Subject: RE: [JN] RE: 112 pre with battery filaments > > > > Hi, > > > > > > Thanks for the corrections. Panasonic has a lead-acid battery rated at > > > > 6.5Ah for 20 hrs. At 250 mA, I calculate nearly 24 hrs on that one. > > > > >yes, this is more like a C/20 rate (actually C/26). > > >so you don't really need to make adjustments to available capacity > > >based upon discharge rate. > > > > > >6.5AH / .25A = 26 hours. > > > jim wrote: > > > Yes, but it will not be giving 6V anymore and we do not live in a > > theoretical world. Take about 70% of that for effective playing time. > > > sure. > > i look at it the other way around. > > he's already mentioned that his max. run time will be less than 8 hours. > > so this guarantees rather shallow discharge cycles, which SLA > batteries prefer. meaning he won't have to replace the batteries in > six months.... ;) > > actually, these batteries will probably give close to the calculated run-time, given the resistive loading. > > the voltage performance issue that you are alluding to is more > of a concern in constant-power application (the most common applications - feeding a dc-dc converter...or a motor). > > > >you really don't want to charge cells in parallel. > > >this is because you can't guarantee that they will share equally. > > > > This is even more so in series. I used to charge my 32 batteries (12V) on a > > single lab supply. It takes a while longer to get them all charged, but in > > the end they do all fill up the same. This is not to say this is a good way > > of charging. Batteries suffer this way as a battery with fuller charge will > > pass (full) current to charge another battery that has been drained more. > > > yeah. > we talked about this before... > > individual chargers are the way to go.... ;) > > > Best thing to do is use a relay (dual pole, dual contacts) to switch to > > it's own little charger. A 317 costs about $1, plus a few resistors and a > > transisitor, in all that should cost about $5 for an entire charger. Add > > $2-3 for the relay (Siemens has very nice gold-clad silver contact relays) > > and you're done. Two of these will not hurt your bank account ;))) > > > amen... > > > >you can probably build a single DC supply, then use a current source > > >circuit (like a LM317 + resistor) for each battery. > > > > Voltage source... > > > right you are. > > you can simply build a "float-charger". > this would be a DC regulated supply set to about 2.2 to 2.3V per cell > (6.6 to 6.9V for your 6V battery). it think 6.75V is the recommended > float voltage for most manufacturers. > > check the temperatures on the first few charges. if the batteries are getting too hot, reduce the voltage a 10th... > > would be a good idea to try to implement current limiting of some sort > in each circuit. find out the max. rate for that cell. > > it's probably around 2.5A. > > > Yes indeed, this is what I do in my chargers. One big > > rectifier and capacitor and then split to 8 charger circuits. > > > > >just figured that if you were taking the plunge.... ;) > > > > There's an address in the UK (www.steatite.co.uk) that has really cheap > > 12V/2Ah batteries ($6-8 each). If you live in the UK this might be a good > > oppertunity. I would have done it already, but shipping (even to just > > across the channel) is about 4 times that due to weight. > > > > > > > > > > Regards, > > > > > > Jim de Kort > > jim@vt52.com > > > ========================================================================= From: "Danielak, Robert M" Subject: RE: [JN] RE: 112 pre with battery filaments Date: Thu, 07 Dec 2000 17:40:32 -0500 Source: Sound Digest Archive v02.n755 depends upon the manufacturer of the cells/packs. the ubiquitous 18650 cells themselves (made by sony, sanyo, etc) have built-in PTC devices and pressure switches to protect them from overcharge and over discharge. some battery packs have external protection and cell-level charge-management circuits. > ---------- > From: Aigner Josef, Dr.[SMTP:j.aigner@igk.co.at] > Sent: Thursday, December 07, 2000 5:11 PM > To: Danielak, Robert M; Joenet (E-Mail) > Subject: AW: [JN] RE: 112 pre with battery filaments > > What kind of safety device ? > > Josef > > > -----Urspr> üngliche Nachricht----- > > Von: Danielak, Robert M [SMTP:robert.m.danielak@lmco.com] > > Gesendet am: Donnerstag, 07. Dezember 2000 16:46 > > An: Joe List > > Betreff: RE: [JN] RE: 112 pre with battery filaments > > > > NiMH are pretty expensive. > > besides that, they require a more complicated charger. > > > > their main benefits include a bit higher energy density > > (they're smaller), decent cycle-life, and they're more environmentally > > friendly. > > > > they are very quickly being overtaken in the market by > > Lithium Ion (Li Ion). > > > > i did not suggest Li Ion because the voltage is all wrong > > (3.7V average), and because they need special charging techniques, > > as well. > > > > also, any commercially available Li ion batteries contain > > control/safety electronics which would probably defeat the purpose > > (at least philosophically) of using batteeries on toobs.... > > > > bob.d. > > > ---------- > > > From: Simon Busbridge[SMTP:S.C.Busbridge@bton.ac.uk] > > > Sent: Thursday, December 07, 2000 2:37 AM > > > To: Danielak, Robert M > > > Cc: Joe List > > > Subject: Re: [JN] RE: 112 pre with battery filaments > > > > > > NiMH? Supposed to be as good as NiCad but without the memory effect. > > > > > > Never used them personally. > > > > > > Simon > > > > > > Simon Busbridge, BSc(Hons) PhD CPhys MInstP > > > School of Engineering > > > University of Brighton > > > Lewes Road > > > Moulsecoomb > > > Brighton BN2 4GJ > > > UNITED KINGDOM > > > > > > Tel: 0044 (0)1273 642542 > > > Fax: 0044 (0)1273 642327/642301 > > > e-mail: s.c.busbridge@bton.ac.uk, scbusbridge@hotmail.com > > > > > > > > > > ========================================================================= From: StepHydro@aol.com Subject: [JN] 1200VDC plate on an OPT Date: Wed, 17 Mar 1999 14:13:47 EST Source: Sound Digest Archive v02.n078 JN denizens, I have a friend who is building a pair of PP 845 monoblocs. He wants to run 1200VDC on the plates. His transformers are 80 Watt Peerless. Does anyone know if Peerless used insualtion on the OPTs that would withstand that voltage? Cheers/Carron ========================================================================= From: Allen Wright Subject: [JN] 120dB ESLs Date: Thu, 29 Mar 2001 04:42:02 -0500 Source: Sound Digest Archive v02.n847 dnb said "Please tell us more!" The brand is "monitor DB" and they will be shown at this years Amsterdam AES by Beyerdynamic (the headphone people) as a potential theater speaker! It's approx 170 cm high by 50cm wide, a single curved panel like a Martin Logan. It is not vertically segmented. Looks good but not slick like a ML. The associated subwoofer is a matching box of the same frontal size, but perhaps 70cm deep, using 4 ~10" cone woofers in a sealed box. It is bi-amped, electronically crossing at 115Hz. The designer is a small commercial speaker manufacturer - doing a range of box speakers that he sells only in Germany through a dealer network. He does no advertising, doean't exhibit at trade shows - seems not to need to. No website! What I heard was no lashed up prototype - but a full for sale product. Price - DM35,000 (approx $US15,000) and comparing them to anything else hi-end hifi they are way underpriced. I asked what happens when they are overdriven - what's the failure mode? He said "Don't know - it's never happened. At some technical university they put in 1200 watts and the measured distortion was lower for the speaker than the amp..." Allen (VSE) ========================================================================= From: "J. Gordon Rankin" Subject: Re: [JN] 120dB ESLs Date: Thu, 29 Mar 01 07:55:16 -0500 Source: Sound Digest Archive v02.n847 Allen, So is this 120dB per watt or capable of 120dB? Do they have a website? Gordon =====> Wavelength Audio, ltd. <===== mailto:waudio@cinti.net mailto:wavelength@fuse.net http://www.WavelengthAudio.com ph.fx. 513-271-4186 USA ========================================================================= From: David Barnett Subject: Re: [JN] 120dB ESLs Date: Thu, 29 Mar 2001 11:03:42 -0600 Source: Sound Digest Archive v02.n848 On Thu, 29 Mar 2001 07:55:16 -0500, "J. Gordon Rankin" wrote: >So is this 120dB per watt or capable of 120dB? I believe it was previously stated that the sensit