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 Post subject: Chassis ID?
PostPosted: Mar Thu 16, 2017 10:40 pm 
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Found this recently, is anyone familiar with this chassis?
it's obviously a 6BQ5 PP amp, I'm just wondering what it came out of.


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 Post subject: Re: Chassis ID?
PostPosted: Mar Fri 17, 2017 2:51 am 
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I'd say it looks like it came out of an electronic organ.
-Chuck


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 Post subject: Re: Chassis ID?
PostPosted: Mar Fri 17, 2017 3:05 am 
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That's my first impression as well based upon the markings and the types of connectors used. Those are very commonly seen on organs.

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 Post subject: Re: Chassis ID?
PostPosted: Mar Fri 17, 2017 5:04 pm 
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Organ, Ahh I didn't even think of that, thank you gentlemen, I'm thinking it's worth a restoration, I have most of the tubes in stock, will have to check the transformers for continuity first before I go ahead with this.

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 Post subject: Re: Chassis ID?
PostPosted: Mar Sun 19, 2017 1:49 pm 
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Is it Push-Pull-Parallel with the 6BQ5 outputs? I think I only see one output transformer.

But, I have been proven wrong many times. :wink:

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 Post subject: Re: Chassis ID?
PostPosted: Mar Sun 19, 2017 4:07 pm 
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It sure looks like it, the brown and blue wires from the output transformer run over to pin 7 on two of the 6BQ5 sockets, which are connected to pin 7 on the other two 6BQ5 sockets through those light blue wires that are coiled up to create some small inductance. They must have had issues with spurious oscillation or ringing.

You have to wonder why they would design this P-P-parallel instead of just using two more powerful output tubes. At that point in time, the cost would have been about the same.

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 Post subject: Re: Chassis ID?
PostPosted: Mar Sun 19, 2017 4:42 pm 
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Don Cavey wrote:
Is it Push-Pull-Parallel with the 6BQ5 outputs? I think I only see one output transformer.

But, I have been proven wrong many times. :wink:

It is a mono PPP, I did a little more digging since my last post and found this thread from March 2014

http://antiqueradios.com/forums/viewtop ... 3&t=246324

it's from a Baldwin model 71 or year 71, not sure, as noted in this auction

http://www.ebay.com/itm/Baldwin-Mono-Tu ... 489a0e528c

More photos of a similar amp found online:
http://www.canuckaudiomart.com/details/ ... es/128230/

Dennis, I was wondering about those home brewed coils as well, good catch.

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 Post subject: Re: Chassis ID?
PostPosted: Mar Mon 20, 2017 12:21 am 
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Mr. Detrola wrote:
...
You have to wonder why they would design this P-P-parallel instead of just using two more powerful output tubes. At that point in time, the cost would have been about the same.


Dennis, Magnavox was famous for using PPP 6V6GT tubes in amplifiers. I would have to wonder if it possibly had to do with total tube count, or to impress the purchaser. Don't know...

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 Post subject: Re: Chassis ID?
PostPosted: Mar Mon 20, 2017 12:36 am 
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Or maybe they used singles of these tubes in other models and didn't want to stock another type.

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 Post subject: Re: Chassis ID?
PostPosted: Mar Mon 20, 2017 4:41 pm 
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It saves them from a high voltage power supply. A 450 volt supply is much more expensive than one for 320 volts, due to the need for 600 volt capacitors or capacitor stacks, etc.

-David


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 Post subject: Re: Chassis ID?
PostPosted: Mar Fri 24, 2017 1:06 am 
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Early 1960s vintage; the date code on that Sprague capacitor is 30th week of 1962.

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