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Need Help Identifying a Make/Model of a tube amp

nabeelsayegh

nabeelsayegh

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Really hoping someone can help me out here. I have a pair of these amps that came in for restore. They said they were Dynaco amps, but I dont think so. I though maybe Fisher or something like that, but still no hits on a visual match. Not really matching any design i have seen before. The numbers stamped on the chassis are not lining up to any obvious make/mode and even AI sites are having a hard time identifying it. Does anyone recognize this? I really need a schematic for this guy and even more so, I need to identify what the value of the dual section can capacitor is that is brown in color. The metal cans I can identify no problem...but this one is a mystery.
 

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here are more pics...

The last pic is of the cap that I am trying to identify.
 

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not Fisher or Dynaco, I can say that with pretty good confidence. Appears to be using 7591 for the bass channel and 6V6 for the treble output, can't be too many things using that arrangement. This may not be stereo either, I don't see 3 channels worth of output connections. Looks like just a single bass/treble output.
 
Definitely not stereo, it's mono. The configuration of this unit implies that its supposed to work with something else...but both of these came in what I think are custom built wood enclosures with a metal mesh top cover. What they are, they were meant to be used as stand-alone amplifiers. Its a definite mystery. I know this may not mean much, but all the tubes in both units are Magnavox.
 
nabeelsayegh said:
They said they were Dynaco amps, but I dont think so.
Click to expand...
Yeah, I don't believe Dynaco ever used the 7591 tube.

Whatever the original use and manufacturer, they chose the more expensive (at the time) 7591 over the 6V6GT or 6L6GC. So I would guess the unit was built for a higher-end market.

:idea:
 
Makes for a cheaper circuit though. 6V6 and a 7591 need more or less the same driver circuit, but a 7591 can do about double the wattage. 6L6GB/5881 are very similar output but roughly double the drive signal required.

also they were old news, 7591 was the cool kid on the block, nobody wants old pre-war tubes, we need the newfangled latest and greatest.
 
This looks Magnavox through and through- from the chassis stampings and ink stampings, type of =edit: plastic= and phenolic connectors, part numbers on the power resistors, chassis, transformers, etc- It just has that feel. The Magnavox tubes on it helps push it that way as well. Think mono console of some sort.
 
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Not impossible but I've never seen or heard mention of a Magnavox 7591 amp. They made a number of bi-amps but all 6V6 so far as I've ever seen. They quit making mono consoles possibly about the time the 7591 was introduced. I think about 1957 was the end of that, and the 7591 came out in '58.

I believe those are actually Amplok connectors with the flat blades, not Molex which typically used round pins.
 
You know, this may have been manufactured by Magnavox for a jukebox company. Many jukebox features- There is a relay under the chassis for the mute circuit, a "Master" volume adjustment, a treble adjustment, and =edit: 0B2= regulator and 7591 (both common in jukeboxes) and of course bi-amping.
 
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nabeelsayegh said:
here are more pics...

The last pic is of the cap that I am trying to identify.
Click to expand...
the 636 #'s come up Sheldon Electric company, divison of Alide Ellectric products corp Inc, IRVINGTON 11 , NJ ??? from the chassis in photos. is mono possibly two transformer one for low freq, the other for mid and high.
 
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It looks very resembling the amp that came out of Cordovox accordion amplifier enclosure. The one I had was only one channel, PP7591 with 6SN7 driver and 5U4 rectifier and a choke. This one has the same looking transformers but has additional, perhaps treble channel. I always thought those amps were build for Cordovox by Magnavox, if they were not the same company to begin with. Construction looks very similar to Magnavox style.
 
20260812_205947_resized-jpg.3817569

EIA of 320 = Trav-Ler Karenola Radio and TV Company, Chicago, IL. From the 1962 EIA chart that I have.

1959?, 6th week.
 
I believe (similar to Magnavox numbers) the top number with a dash would be an internal part number, the bottom number would be EIA code (141) would be Coil Engineering.
 
The tube count is: 2 x 6v6, 2 x 7591's, 3 x 6EU7's and 1 5U4. It would appear that whomever 'hacked' this before i got it, tied together what appears to be both output channels together. I am not sure if this is a 'thing' or not. My instincts tell me this would be a no-no...but I am not very strong on tube design as I am with solid state. (There is a jumper across the T and B speaker terminals....i assume this is supposed to be the treble and bass outputs.) Also, the relay underneath the unit was bypassed. The big mystery is what is the value of this dual section capacitor. Both sides are tied together on the underside. I am guessing a dual 20uf/450 or something close to it. If anyone had to guess what a safe substitute would be, I'd love input on that. Evaluating the circuitry, I've created a schematic for review.
 

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Yowza- Is that a high voltage or filament winding? Glad you did not plug a pre-amp into that "input". Maybe they were running HV out to an accessory chassis? That's crazy.
 
wparks said:
I believe (similar to Magnavox numbers) the top number with a dash would be an internal part number, the bottom number would be EIA code (141) would be Coil Engineering.
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agree, and that makes the date code 1259, so roughly March 1959.

Bridging the bass and treble outputs would not make this properly full range. It might work, but it won't work properly.

no idea whats going on with that power supply segment. Bringing voltage out on an input jack doesn't make a lot of sense unless its phantom power for a condenser mic, but thats typically 48volts. If thats tapped off the main HV winding I suspect thats far too much.
 
What to thank everyone that has chimed in thus far. Been researching all the suggested brands but unfortunately, nothing has come up that comes remotely close this this design or layout.
 
The number starting with "320" is similar to Magnavox transformer part numbers. "141" is Coil Engineering, in Indiana, as was Magnavox.
 
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