Film-Tech Forum ARCHIVE: 1930's DeVry Theater amplifier

This is topic 1930's DeVry Theater amplifier in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Ian Shackleford (Member # 5819) on 07-30-2010, 01:46 AM:

Hello,

I collect and restore antique radios and similar items. I picked up a Devry theater amplifier the other day, and can not find anything about it. The largest (power) transformer says 144H 110volts 60cy 100w. That seems to me to be the model , 144h. The amp is from ~1930. it uses 2-57's or 58's 3-45's and an 80. Some one also added a 6v6 and a small 6.3v filament xformer at some point. The Amplifier has a slanted face, and a large orange celluloid control panel, that is illuminated and 4 knobs.
I am looking for the schematic and any information related to this.
Thanks, Ian

Posted by Tony Bandiera Jr (Member # 2365) on 07-30-2010, 01:25 PM:

Hi Ian and welcome to Film-Tech. You'll find a lot of helpful (and colorful) characters here. [Big Grin]

The part number of the transformer makes me think it is a re-badged Western Electric or even Altec amp. You can try looking up some Western Electric or Altec amps with the same tube compliment and I'm willing to bet you'll get a schematic that will work.

I wish my colleague Conrad was still alive, he knew all about that older gear.

Posted by Jeff Taylor (Member # 443) on 07-30-2010, 01:32 PM:

I'm guessing that 6v6 and xfrmr may have been part of an oscillator circuit for the exciter lamp supply or perhaps the phantom voltage for an old photoelectric sound pickup.

Posted by Gordon McLeod (Member # 33) on 07-30-2010, 07:23 PM:

Devry did use a high frequency AC excitor lamp powersupply

Posted by Ian Shackleford (Member # 5819) on 07-30-2010, 10:00 PM:

The 6v6 Really does NOT belong in the amp. It is clear it was a later addition. The transformer powering its filament is from a company that made replacements for things. The Amp has mic and phono inputs, tone control, master volume, mike/phono volume, and an on off switch. It seems that it is only for the sound, and not for the projector.

Posted by Jeff Taylor (Member # 443) on 07-31-2010, 09:19 AM:

Understood--just opining as to why someone added it and what purpose it was added to address.