Three Channel Organ Amp - NEED HELP

[JohnLocke88]

Hello everyone. I recently purchased a three channel organ amplifier on eBay. From my initial research, I have tentatively concluded that it is a Baldwin amplifier. I want to try to use it to drive some music speakers (probably vintage Polk Audio Monitor 7s or 10s.

The tube complement is (8) 6BQ5/EL84's, (3) 12AX7/ECC83's and (2) 5U4 rectifier tubes. (Included are the (2) 5U4 rect tubes; As such I will need the remaining (11). Any suggestions on brands? I saw some cheap NOS Russian stuff on eBay; this a good bet?

Also, If anyone knows anything else about this amp, I'd appreciate all the help/information you can offer.

http://i763.photobucket.com/albums/x...88/Baldwin.jpg

Video of another one (I think the same one) playing: http://video.google.com/videoplay?do...7468922418947#

[Goodwill_HiFi]

I have a similar amp, if not the same, sitting on my storage shelf in the basement. I got it off of Craigslist. I'd like to get it going at some point. I know next to nothing about tube equipment....... those light bulb thingies get hot right?

[djnagle]

I wonder where the other two OTs are???

[PatA]

What is the potential of these amps in a home audio application? I'm assuming mono output only?

[archie2]

That might have driven the organ bass only. Dunno. I don't see three OPTs.

[cademan]

Originally Posted by djnagle

I wonder where the other two OTs are???

A friend of mine has that exact same amp! There are two identical output transformers under the chassis!

Also, I believe it is a 4 channel amp. Two 6BQ5's per OPT on PP.

[GordonW]

Last one of those I saw, IIRC, was three channel. Four 6BQ5s on the big OPT on the left rear of the chassis (PPP), and two 6BQ5 each on the two transformers under the chassis.

Regards,
Gordon.

[cademan]

Originally Posted by GordonW

Last one of those I saw, IIRC, was three channel. Four 6BQ5s on the big OPT on the left rear of the chassis (PPP), and two 6BQ5 each on the two transformers under the chassis. Regards,
Gordon.

You're probably correct as I was not able to study my friends up close, but he did show me the underside and the two hidden transformers.

[JohnLocke88]

Upon further discussion with seller, looks like there is only one input, and three outputs; There are two trans on the bottom for the "weaker" channels.

Does anyone know if it is possible to modify this to accept two/three discrete channels of input?

[cademan]

If you are tech savvy, you could probably see where each signal inputs to each of the 12AX7 tubes and split the inputs from there. Although I do not have the unit in front of me, I believe each 12AX7 tube drives each perspective channel individually.

EDIT: Pin #2 on each 12AX7 is the input. They are probably tied together from the single input so you could probably seperate them from there.

[JohnLocke88]

Originally Posted by cademan

If you are tech savvy, you could probably see where each signal inputs to each of the 12AX7 tubes and split the inputs from there. Although I do not have the unit in front of me, I believe each 12AX7 tube drives each perspective channel individually.

EDIT: Pin #2 on each 12AX7 is the input. They are probably tied together from the single input so you could probably seperate them from there.

Awesome; I am not super tech savvy, but I can learn. I have the personality that if something is possible, I'll figure it out.

Knowing that it is physically possible is the key

[Goodwill_HiFi]

I just took a quick look at mine...... it's a single plug, but it has 5 possible conductors. I didn't look at the underside.

[hatrack71]

Are all three output trannys the same? Perhaps throwing a potentiometer volume control on the channel with four 6bq5s and attenuating it down to match is the answer.