Ultimate Hammond Conversions thread

[maxkracht]

Thanks dragonbat, no need to make things any more challenging than you want to. You can get a great sounding amp out of a lot of old organs just by replacing some caps, slapping on input and output jacks, and maybe volume and tone controls.

The guy I have been making these things for is going to try and sell them for as much as he can, regardless of how nice they look on the inside, so I try and make things as good as possible out of respect for the end consumer. I see a lot of slapped together amp projects with visible problems selling to unsuspecting consumers for big bucks and I don't want to put any of that into the world. Gotta make stuff as reliable as I can so I can sleep at night. I also just like to design things...

[xk49w]

In 2009, I built a guitar amp for my nephew (in high school). I got the AO-35 from Bob Schleicher (RIP), the Oakland, CA Hammond organ super tech. I had done work for him for years (Leslie solid-state relay). I told him there were people converting AO-35s into guitar amps and selling them. He was way ahead of me. He'd sold a pallet of them to someone that was doing that. I asked him for one and he insisted on sending it to me no charge. Nice guy.

I don't recall what I based the schematic on. It looks like a mix of an AC10 and other designs. It has a cut control, no feedback, and a buffered tone stack. As to why I paralleled the two input stages, I had a spare one so why not?

The closed-back cabinet has a Jensen P12N behind a speaker directivity modifier (the donut shape behind the grill cloth).