1950's Conn Organ Amplifier Chassis

[junkin8ez]

Got this off of Ebay with hopes of converting it to a guitar amp.
Does anyone have a schematic or know the model #? Or am I wasting time?
vintage 1958 conn 2 channel amplifier.

1 channel is push pull 6L6 the other is push pull paralell 12v6

uses 2- 6L6, 4- 12v6, 3- 12ax7, 2- 12au7 & 5u4 & 5y3 rectifiers.

weighs 25lbs and is 21" long.

has rca inputs & level adjustments for each channel. Has input for tremolo.
Any help would be great.

[soundmasterg]

Best advice is to draw out what is there on a full size layout, and from that draw up a schematic. Then you can study what you have and figure out what to modify. I did this on a 1964 Conn power amp chassis with three power amps in it, and decided to make a seperate preamp chassis with three preamps in it, for an end result of three amps in one head. Still working on it 6 years later...haha. It does function however and sounded good in two channels before I decided to redo how I was doing the preamp chassis layout. The layout and schematic that I drew up were invaluable when I was trying to decide what to do with it.

Greg

[6267]

There are not 2 channels, there are three...at least on mine. Two 12v6 used the little OPT, 6L6 used the big one, and the other 12v6 do something i have never seen before...It might be a variable frequency or regulated power supply...not sure...anyway, between the anodes of the two 12v6 that are not connected to an OPT, there is a *huge* poly cap, and the cathode bias resistor is 350 ohms and not 250...additionally, it looks like the seperate 12ax7 might have been an oscillator (my chassis is in storage right now so I can't remember) driving the grids. Crazy stuff, but it goes along with the 0A2 and dual recto setup this thing has...

It'd make a great chassis for an octal dual showman or something I wish I knew the wattage ratings of those transformers though, and/or their actual ratios.

[6267]

Don't know if you got it to turn on yet, but there is an octal socket which was used for power switch and pilot lamp, and another which has the two speaker leads...There's a mini 5-pin adaptor which has to be jumpered, the connector divides the preamp...I got it to power up ok, although I had to rewire all the filaments for 6v6 instead of 12v6 and I didn't have 6l6s (i used some old 6ca7s, close enough to see if the oPT worked)...seems like these must have been driven by a fairly hot signal, I was having trouble getting too much output. That power transformer is a beast though, huh?

[Tom D]

Chassis number?

I know this is an old post. If you are still sitting on this amp, I'd be interested in the chassis number that should be on the TUBE id chart on the side. I'm restoring my Dad's old CONN organ and looking for and Amp.

[RWood]

Nice schem, Tom, thanks for posting it. That one has been elusive. Do you need help repairing your Dad's?

I became very familiar with that amp when I gutted one and converted it to a bass amp for a friend. See pics.

RWood

[Tom D]

RWood, Thank you for the offer of help. Your Amp looks great. Since I posted this message, I discussed my project with a good friend that is a retired electrical Engineer and Extra class Amateur Radio Operator. He has taken an interest. We are going to start by going through the AMP and replace what is needed and going through the Specs. We will then go through the rest of the tone generators and circuits one step at a time. There are tons of wires and contacts so there is no guarantee that we will be able to get it to work like new. My Dad's CONN is a 532

Tom D

[luthierwnc]

This thread seems to have a long life!

Did you guys ever measure the Z-outs on the two on-board output transformers? Thanks, Skip

[RWood]

Did you guys ever measure the Z-outs on the two on-board output transformers? Thanks, Skip

I measured the larger one with the black endbell, T2 on the schematic that is used for the 6L6s. It has a 4Ω tap for the speakers (for two 8Ω in parallel) and a 2Ω tap for the feedback circuit.

I did not measure the one for the 12V6s, T3 but I still have it on a shelf. Let me know if you need the Zs on that one.

RWood

[TRC]

I have this amp and would appreciate any concersion info that you can supply. I have

First post, sorry about the header. I am looking for the conversion info and any info would be greatly appreciated. My amp is in total working condition.
Thanks

Got this off of Ebay with hopes of converting it to a guitar amp.
Does anyone have a schematic or know the model #? Or am I wasting time?
vintage 1958 conn 2 channel amplifier.

1 channel is push pull 6L6 the other is push pull paralell 12v6

uses 2- 6L6, 4- 12v6, 3- 12ax7, 2- 12au7 & 5u4 & 5y3 rectifiers.

weighs 25lbs and is 21" long.

has rca inputs & level adjustments for each channel. Has input for tremolo.
Any help would be great.