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MagneQuest/Peerless Forum

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In Reply to: RE: good detective work.... posted by mqracing on February 09, 2009 at 12:42:01

Audio Anthology volume 3, page 16ff. "The Maestro - a POWER amplifier," Sarser and Sprinkle. Audio Engineering, 1952, originally. (For those who don't know, that journal split into Audio Magazine and the Journal of the Audio Engineering Society a few years later.) This is real historical Golden Age stuff.

Here's an excerpt:

"... so a conference was held with E. B. Harrison, of Peerless. On hearing the problem hesaid, "I think I can do it." Subsequently he has admitted it was a tough one. However, Harrison designed and built an output transformer for the 6146, and although originally built especially for this first amplifier, it is now in the Peerless line as type S-268-Q."

The amp itself is Class AB with the accent on B - quiescent current 58mA, full power 254mA. So he transformer primary halves must be very tightly coupled indeed. The transformer, tested with a matched impedance rig, is down 1dB at 10Hz and 100kHz. 800 henries at full power, leakage 7mH. Wow.

Last I heard, several years ago, David Sarser is still around and would LOVE to get his hands on a pair of these.

I would speculate that a pair of 845s in deep class A, no feedback, would be spectacular with this. Anybody up for a "Seth on steroids"? Be afraid - be very afraid!

Follow Ups:

a bit more trivia for PJ.... - mqracing 07:30:41 02/10/09 (2)
Did you know that Peerless also made an OEM (slightly modified) version of the S-268-Q?
The 268 is utterly rare... I have only ever seen one pair and one single unit offered up in the past twenty plus years...
I'll have to pull the folder but this was an incredibly difficult trans to build... and even Peerless had far more rejects at the end of the line than good units to sell. This had nothing to do inherently with the design (from an electrical POV) but that the secondary was wound with very, very thin copper foil and was insulated with an equally thin single piece of kraft paper... and what would happen is that the foil would short through the kraft from layer to layer...
I suspect this is a solvable problem today--- wherein it would be possible to get the foil with a film dielectric bonded directly to the copper foil--- which would eliminate the foil and kraft paper slipping and then shorting--- other trick is that the foil must be absolutely burr free--- not even a hint of even-ness or rough edges to eliminate cut-through.

Other difference is that Peerless offered the S-268 as a catalog item--- and given the difficulty of manufacture--- especially in volumes representative of it being a catalog item--- they quickly realized it was not optimized for "mass" production. I think that in a format of doing a very limited run--- with careful one person construction of the coil and then the assembly of the unit--- it would be possible to build these and make them bullet proof--- or at least as bullet proof as other standard offerings---
but we're looking at much, much higher costs all around. these units made today with what I see as the challenges in materials sourcing and then in the utter care of one by one assembly--- I think we'd be looking at a min of $800 each. And maybe in the range of a grand to $1250 each depending on core goodies selected and etc...
it's neat idea--- and worthy of Peerless' 75th anniversary--- but it might not actually be practical from an economic point of view. I'm not sure we could get enough units sold to make it pay off.
The modified OEM version of the 268 would lessen all of the above specialty concerns in terms of materials sourcing and the specific manufacturing issues. my other concern (realization) is that push-pull applications in today's DIY market is really much more limited than coming up with say a neat SE project.
So, I am also considering several other Peerless designs--- and in a conversation with Nullspace last evening we were kicking around the idea of a hot rod TFA-204/2004. Which I know your also a big fan of. There are still a few neat materials related tricks that we could look at doing with a 204/2004.
Other designs worth looking at is the TL-404--- and doing some special stuff with cores, insulations, and magnet wire.
Therefore, this is going to take a lot of mulling over and reflection--- before choosing a final project to mark the dual anniversaries of Peerless and MQ.
We'll be discussing this later and at the appropiate time I will post further details, thoughts, and invitations for comments from our end users and OEM's.

MSL

Builder of MagneQuest� & Peerless� transformers since 1989

Edits: 02/10/09 02/10/09 02/10/09
- RE: a bit more trivia for PJ.... - pistoljoe 14:46:55 02/10/09 (0)
  I would just say that there are lots of cool pieces available for SE, but not as many for PP. I personally prefer PP, although I can't say that five times fast.
  
  So, anything special from that era of peerless would be a treat and something I would certainly be interested in buying.
  
  I'll keep my eyes peeled for whatever you decide to wind.
  
  Joe
- RE: a bit more trivia for PJ.... - Caucasian Blackplate 11:59:29 02/10/09 (0)
  How many units would you need to sell?

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