Hammond tranny question

[Nalo1022]

A while ago I salvaged most of a Hammond organ out of the garbage. Recently my want for a tube driven reverb unit has increased, but sadly I don't have the money for one. The organ has a reverb unit, but after some research it seems that making it a standalone unit with the existing circuit isnt really possible. I am wondering if the transformers that it has would be sufficient for use with a 6g15 circuit. The reverb unit is a Hammond AO35

thanks to this forum I was able to find the schematic.
http://www.captain-foldback.com/Hamm...atics/AO35.JPG

I am good with a soldering iron and I'm not looking for a step by step.

[Chuck H]

The power transformer would work just fine. But the output transformer is the wrong type. At least for use as a reverb driver. The reverb schem shown is limited and unusual, at least to me. Is there another transformer and tube in the console for driving the reverb? The amp itself is for amplifying the reverberated signal. But I cannot tell on the schem how the signal gets reverberated. My gut tells me that there is a reverb driver tube and trandformer somewhere that drives the input to the spring tank. That would be the other transformer you need for a 6g15 type circuit.

FWIW some builders have modded those old Hammond reverb amps into guitar amps with good results. But if you don't need an amp, and you do want a reverb...

Hopefully "most of a Hammond organ" included the reverb driver transformer.

Chuck

[52 Bill]

...The reverb schem shown is limited and unusual, at least to me. Is there another transformer and tube in the console for driving the reverb? The amp itself is for amplifying the reverberated signal. But I cannot tell on the schem how the signal gets reverberated. My gut tells me that there is a reverb driver tube and trandformer somewhere that drives the input to the spring tank. That would be the other transformer you need for a 6g15 type circuit.

The reverb tank input is connected to the internal speaker of the organ, so there is no driver circuit. The output of the tank goes to the input of this amplifier, where it is amplified through its own speaker.

[Chuck H]

Thanks Bill. I'm not familiar with that console organ (or any for that matter).

Thats clever. Gibson experimented with similar circuits early on.

Well... Nalo, You could still use the power tranny. But you'd have to get a second tanny to drive a tank if you want to build a 6g15. Save the OT you have for a future project.

Or you could just build a regular non reverb 15 watt amp from the parts you have.

Chuck

[52 Bill]

Thats clever. Gibson experimented with similar circuits early on.

Yes, there was a Gibson and a Maestro version. Ampeg also did this early on.

...Or you could just build a regular non reverb 15 watt amp from the parts you have.

Well, he could actually drive the tank with the output of this amp, and then only build a recovery/mixer circuit. The 15 watts would really be overkill here, but it would work.

[Chuck H]

Well, he could actually drive the tank with the output of this amp, and then only build a recovery/mixer circuit. The 15 watts would really be overkill here, but it would work.

True enough.

On that same line of thinking...I've been working on an amp that drives the power amp into a square wave. The guy I'm designing for wants a reverb on this model. But as you probably know, it's hard to get two signals into an overdriven power amp with any integrity left. I will no doubt just include a standard reverb circuit on this amp. But for my personal design vault I want to build a similar amp without the reverb. And then build a second powered cabinet with a reverb built into that circuit to be fed by a speaker driven line out on amp 1. Not unlike the above console organ and Gibson systems. Only mine would include a blender for wet and dry signals so that I could incorporate effects in that loop. I was goint to call it the "juice box". But I think thats been used. The seperate powered reverb was a good idea then and I think it still is.

Chuck