Painful Reality

Hi guys, Just to let you know that my actual SET amp is for sale for the price of parts to finance my next PP2A3 project. I must admit that I am mucho sad to sell these but the price tag of my PP2A3 just keeps adding up and I have no choice to let these monoblocks go so this project can materialize. The picture shows these amps with 300B version but I can convert it to a 2A3 amp for no additional cost. I personally prefer the sound of a 2A3 over the sound of a 300B but other might disagree. No matter what tube you want, if you have to pump out SteppenWolf's "Born to be Wild" at 117 dB from your Klipsches you might look elsewhere! These particular monoblocks come loaded with goodies, a partial list being: MagneQuest cobalt TFA-2004 parafeed OPT MagneQuest EXO-04 plate choke MagneQuest BCP 16 Ni Gc grid choke Jensen copper in foil coupling cap Cerafines in the PSU Black Gates NH serie (non-polarized) as cathode bypass Elna stepped attenuators GE oil DC blocking cap in the parafeed circuit WBT binding posts Cardas RCA jack Zebrawood chassis Copper top chassis plate Silver plated teflon insulated hook-up wire Riken and Mills resistors Contact me for additional details at: jeff.lessard(remove this)@sympatico.ca EDITION... The attachment disapeared again!!!!! to see the photo check a couple of posts below! Thanks

---------------- On 8/2/2003 12:32:39 PM bclarke421 wrote: I've got a stash of NOS RCA 6BG6G tubes, and am knocking around some ideas for using them. 1- Single-ended Pentode design for 2-ch playback system. 2- P-P integrated 2-ch 3- Music instrument amp guitar and/or bass Anyone have any ideas, warnings. etc. Any volunteers to build em? ---------------- The 6BG6C is given on the Duncan web site as a 807 equivalent but with a different pinout. Assuming this is correct, Gordon Rankin had a really nice schematics for a single ended 807 in Sound Practices vol 1 no.2. I think (not sure though) the PDF version of this article is available through the Wavelenght Audio web site. It's a really nice and good sounding amp. One of my friend built it and I must say I was quite impressed. And you must know that I have a STRONG bias against single ended amps with anything else than a DHT. You could also build an "original" Williamson amp which use the 807.

---------------- On 7/31/2003 4:18:01 PM NOSValves wrote: Give me a break I can barely see as it is I felt a migraine coming on before the page completely loaded ---------------- Take some Advil, check the PP 300B schematic, take a deep breath and learn what a real phase splitter is! BTW for the technically curious, a nice overview of the phase splitter can be found at: http://www.bonavolta.ch/hobby/en/audio/split.htm I particularly like this phrase: "In a push-pull amp, you need a phase splitter to produce the two identical but in phase opposition signals to drive the power tubes. Phase splitters are like religions, you belong to one or another and discussions between fans are often emotional." Personally I am pretty much partial to IT phase splitting. So anything else is pure junk and should be destined to oblivion.

---------------- On 7/31/2003 12:49:24 PM NOSValves wrote: I often think the engineers did the schematic layout so to differ from the actual chassis just as some sick joke for the newbie . There is no reason it couldn't of been done more like the chassis layout in most cases. Craig ---------------- Sink your teeth on this Craig! http://www.bonavolta.ch/hobby/en/audio/300b_9.htm This is not from an engineer Al Bryant seems to be the typical old coot with suspenders and yellowed fingers from too many cigarettes. He's been doing 300B PP since the 50s or something. He was "homebrewer of the month" in Sound Practices at one point. BTW for all those eventually interested in tube circuit and horns, treat yourself buy all the Sound Practices back issue on CD roms. All 16 issues that were put out are a goldmine of information. Check this at: http://www.southernelectricaudio.com/sp.html

Ahh you whiners... Isn't it the technicians job to translate into reality the taught of the engineers? Seriously guys, there are a zillion ways to build a layout. I'd say to each his own. This being said, the best reference I found to help translating a schematic into a layout is the Mullard Audio Circuit book or something like this... Anyway search "Mullard Audio Circuit" on any search engine and you should find it. It's pretty much a classic for the tube builder.

---------------- On 7/30/2003 7:29:37 PM mike stehr wrote: Thanks Jeff. I have them downloaded. Pardon my ignorance, I've never seen power run from the center tap of the rectifier filament/heater winding. I'm used to seeing it come off the Cathode of the rectifier itself. ---------------- An "old dog" teach me this trick whenever you have a rectifier filament winding with a center tap. Taking your voltage rail from the CT should make the wear on the rectifier plate equal. Old wive's tale or reality... no idea. DFlip, Thanks for putting this link as a reminder than in this case, ultimate comes with a price... a new preamp for 90% of the people!

---------------- On 7/30/2003 5:34:36 PM NOSValves wrote: Jeff, Why don't your schematics look like the Amity Craig ---------------- Instead of drawing, I'm building...

Last one... for the PWK fans here. Here is a nice 2A3 PP amp that should be a good match with K-Horns (according to Sunnysal of course, me I would personally use nothing but a Krell coz' I am an audiophile!). This is a really simple circuit that is somewhat inspired by the Sun Audio 300B PP amp. Since I am a sucker for punishement, I have to post it with Lynn Olson and Gary Dahl around. For those who don't know, these two guys have designed what must be THE absolute 2A3 PP, the Petite Amity. Compared to the Petite Amity the circuit I am presenting here must be a mere toy. But a really nice toy indeed. If your looking for the ultimate check the Petite Amity at: http://www.nutshellhifi.com/IT-Triode-Amp.gif If you are looking at your first DIY amp instead. Download the attached file. C+ value is missing on the schematics. It should be around 180-190V Jeff L

You missed it Chris... Geez I guess this the "Mission Impossible" forum where the attachement self destruct after being read. Here it is again.

Having found the upload function, and not feeling like working on my PhD, I'll use it. Here is a little SET amp using a WE417A or a 5842 cap coupled to a VT52. This is a nice simple design. Totally different from the Horus soundwise. This amp is not as versatile but if you are exclusively into Jazz trio and chamber music stuff, it might be the ticket. The TFA-2004 OPT might be replaced by a EXO-035 or EXO-036 from MagneQuest. Main drawback of this amp, the VT52 ain't build by anyone since the late 40's I think. You still find them easily though. One solution would be to replace the VT52 by a 6A3 (much cheaper and somewhat common). It's a direct replacement. Be warned, working with a WE417A might be a b**ch due to the extreme bandwitdh of this tube. Credit for this amp goes entirely to Gordon Rankin from Wavelength Audio.

BTW, You'll notice that there is no volume pot on the schematic. Put either one (100K value) after the line selector switch or after the preamp itself (in this case I'd go for a 10K value).

For those interested to build one or just see what it looks like here is the schematic. You'll notice that it is deceptively simple. Pretty much unfashionable too these days. It's nothing new under the sun, the circuit being a simple SRPP. Having tried both a cathode follower and a SRPP circuit for this linestage, I prefered the later. The aim of this linestage was to achieve good performances with a simple circuit without any esoterics (output transformers, CSS, etc.). Is it the ultimate preamp? Me think not... Is it a really good preamp, one that's easy to build and one that won't cost you a fortune (providing you don't go crazy with the parts)? Me think so... My advice only advice, keep the dual chokes and the tube rectification in the PSU. It add to the cost but gives you a much more relaxed presentation. If cost is that much an issue, replace by SS rectification and swap the chokes for dropping resistor (you're on your own in this case). In the eventuality you are interested in this preamp but a soldering iron is a weapon between your littl'hands, ask Erik Madaville politely. Don't be afraid to get him busy. I had to work hard enough to convince him so he will continue the build the Horus instead of me. I feel this little 2A3 amplifier deserves to survive my laziness. (Edition) For some obscur reasons the attached file just disapeared into the digital ether. Go figure!!!

(Edition) Hum... I guess I hit the wrong button. Sorry for this double post

---------------- On 7/29/2003 7:27:55 PM mike stehr wrote: How rough would it be to build a minimalist Pantheon pre-amp? ---------------- Pretty easy. I can send you the schematic if you want. You cannot go more minimalist than it actually is, unless you use one input and skip the input selector.

---------------- On 7/29/2003 12:03:42 PM sunnysal wrote: yeah I know, but "retired" is rarely a permanent thing at his age tony ---------------- Hi Tony, I'm probably lazy enough to stick with my decision. If someone is interested in the Horus though, Erik Mandaville would be happy being bribed in building these. I am certain he would do a really nice job! As for me I will offer my personal amps for sale from time to time. On the selling list soon will be my actual Cobalt SET 300B monoblocks (that could easily be switched to a 2A3). These will eventualy have to make place to my next to be 2A3 PP. Jeff L.

The cathodyne will probably give you the best unloaded voltage balance but it still have one important problem. The output impedance will be much higher for the plate circuit than for the cathode circuit. So in the end your still stuck with problems. Williamson partially soved this by usig a combo cathodyne and a diff amp. The cathodyne splits phase with near perfect balance, but it drives an easier load than pp power tubes grid. There is no such things as free lunch.

That's Joe all right! Thanks Dean, your post made me do a Joe Rosen search on Google and I landed on the site where you got this "Joe Rosen takes on SET"! Fascinating site indeed if a bit hard to follow from time to time. Looking for a nice time waster... Look no further! http://www.lacieg2s.ca/w3terra/ols/audion.htm

---------------- On 7/27/2003 8:03:47 AM sunnysal wrote: Who know´s mike and magnaquest may wind you guys (or me a member of the modest OPT club, lol!) a set of cobalt or other trick OPTs when and if you (we) decide to do it. a few words from Jeff to Mike and I bet he´d make us some. Maybe for Christmas? regards, tony ---------------- I'd be surprised to see cobalt OPT again from MagneQuest. The main problem is the huge investment he has to make to buy those cobalt laminations. There is one or two source worldwide of this type of cobalt allow and users for this are pretty rare (users are found mostly in the military). The high cost of these OPTs makes that no companies will use them, except for Gordon Rankin of Wavelenght Audio (in amps costing 15 000 USD). The result of this is that the market is limited to the DIYers with deep pocket. Probably Mike feels that he reached a plateau where most guys that wanted cobalts got them. The only way I see some cobalt OPT in the future is through purchase groups or if a manufacturer order him a large batch.

I'd pick up the following: A Decware Zen 6BQ5 SET amp A shoebox loaded with Radio Shack full range speaker A Technics SLB200 mounted on half tennis ball A Radio Shack littl' Devil phono preamp A Sony Discman since 0 and 1 are 0 and 1, Cheap CDP are as good as expensive CDP, every knowledgeable guy KNOWS that! That will show them snob Avant Garde Trio owners... JFL P.S. just in case... I was sarcastic...

C'mon on Craig, Who would you prefer to discuss audio with over a beer? A "BigBusaesque" guy or Joe Rosen?

---------------- On 7/26/2003 10:53:16 PM DeanG wrote: How is a rookie like me supposed to keep all of this straight? I thought the 6SN7 was soooooo linear? What did you find with the Moondogs Leo? Something simple hopefully. You did a very nice job on those Erik. I think those Chassis' could stand to be a little bigger though. ---------------- The 6SN7 is really linear if you hit the jack pot. Generally speaking (all right, you 6SN7 devotees, generaly means err... generaly!). But even you die hard 6SN7 fans will have to admit that the sound of a 6SN7 will vary from brand to brand. Used in CASCADE like in the Horus or the Moondog, I've found them to vary from piss poor to excellent, excellent ones being the ones that will cost you a bundle. The 5687 doesn't exhibit this dramatic brand to brand differences in sound. Most examples I know of sounds excellent at the very least. Plus they are dirt cheap...

Well, you got to admit he's usually right (as stubborn as he may appear). Let's take for exemple his opinion on Heathkit or Eico kits in general. They sound good but these amps are filled with crap, OPT or power transformer were blowing as hell (this being said, I like the sound of these amps!). But I still have to find him wrong on something other than a subjective opinion (OK I'll admit this sounds strange... but read his posts and you'll see what I mean). I like opiniated guys in general as long as they've been through their journey (sorry BigBusa but you don't qualify....). Romy the Cat was one of my favorite caracter on AA. He's gone, so is my previous interest there.

---------------- On 7/26/2003 5:13:26 PM sunnysal wrote: Hey Jeff, If you have a new 2A3 PP cooking in your head right now might it be an improvment over my current configuration? let me know... tony ---------------- Didn't you said your PP was your last amp? Or was it your last chassis?

---------------- On 7/26/2003 5:12:19 PM DeanG wrote: I've been reading his posts at The Asylum for the last 3 hours, and this guy is hilarious. In spite of the fact that he's constantly contradicting himself -- the guy is obviously a genius. Anyone here know anything about him? ---------------- Joe Rosen is an opiniated guy but as you described it well, he's a genius and a heck of a nice guy. He's leaning more toward the high power PP amp (eventually SET if not in the flea power SET amp). I think he's the Mdeneen of AA. I wish I had 1/10th of their respective knowledge. Reading his posts on AA is a pure delight.

---------------- On 7/26/2003 8:04:29 PM guy landau wrote: Nice job,Erik. Do you already accept orders? ---------------- If I can pop in, I seriously hope Erik will accept orders, I must admit I'd like the Horus legacy to carry on (hey... I may be humble but I have some leftovers of what could be described as an ego...). While I did really enjoy working on Chris Robinson, Ed Whitesell, Tony Zorn and Dale Walker amps or preamps (all great and PATIENT guys), this was just too taxing for me and my endless PhD to build anything else on order for anyone else. So I don't know about you guys but personally I feel Erik here would be he perfect guy to take it from there. If you want a really nice 2A3 amp, ask Erik nicely! He surely could be bribed into building one. After all, we know that Art teachers aren't that busy! Erik, you showed us some nice workmanship here! Jeff Lessard