Hammond PR-40 Conversion to guitar amp

[Rafu1210]

Hi, theres a few posts here already that talk about Hammond to guitar amp conversions like this one:

1952 Hammond Organ Guitar Amp 1 - YouTube

But I'd like to know about converting my Hammond PR-40 amp like this one:

http://theatreorgans.com/hammond/faq/pictures/pr40.jpg



... into a hopefully awesome sounding, overdriveable guitar amp. Its already got a great spring reverb in it and loads of valves but it sounds pretty clean with my hammond through it. I'd want to still be able to use it with my hammond but also have the option of putting other instruments through it. Its a beautiful old bit of wood so if I could make it into a really useful/versatile studio amp I'd be really happy.

In another post on this site somebody says:

"The best one to play with would be the PR-40 tone cabinet amp - it had three channels - two like the one you've got and one with four output tubes for the bass. The box had a 15" bass driver and a pair of 12" - one in the front and the other in the top..."

If this worked how would it compare to a classic guitar amp like a fender twin?

Any thoughts?

 

[Nigel Goodwin]

If this worked how would it compare to a classic guitar amp like a fender twin?

Any thoughts?

I would expect it to be far higher quality, as it's designed that way - guitar amps are designed to colour and distort the sound. If you want a clean sound, that's fair enough, and I've used a Fender keyboard amp a number of times as a guitar amp - and once for both bass and guitar - and it's worked and sounded fine. But if you're after the dirty distorted over driven valve sound you'll need to add more gain, and perhaps unbalance the output stages.

 

[scrimpu]

If you mod this amp to get an overdriven guitar sound its not going to work well with the organ anymore. An electric guitar has only a fraction of the organs output signal. I would suggest you leave it as is if you want to keep using it for organ and use a preamp or pedal with it for guitar.