Building AMP from a "hammond-style" organ.

[TCDK]

Hi

I own a huge old Hammond-copy orgran, with a huge build in tubeamp.

I was thinking in building an guitaramp with the tubeamp part from the organ.

Anyone who has some information on this type of building?


Best regards
Torben
Denmark

[greg]

I have built 3 or 4 amps from old organ chassis. Please learn from my mistakes: GUT IT FULLY! Remove the terminal strips, and everything else you won't be using. Remove the old filter caps and toss them. You will be much better off starting from scratch. The only thing that I usually keep is the heater wiring to all of the tubes and the rectifier wiring. Remove all of the rest of the wires to the tubes. Build your new amp on a terminal board - don't reuse the old board or terminal strips from the organ. It takes way too long to clean it all up.

You'll need to determine the load your output transformer wants to see, figure out what the current tube configuration is to find out what you could build it into.

Anyway, the long and short of this is that if you are new to amp building, I recommend getting some experience building a kit before going this route. It has historically taken me about 50 hours to gut an organ chassis and build an amp vs about 10 hours to build a kit.

I'll never do it again! I'd much rather harvest the transformers and build something new (and clean).

Good luck,
Greg

[R ski]

Project

I will strongly agree with Greg, on the build with respest to the chassis.
The splitter is the tone bone. Other HiFi configuarions don't sound
so good, when be pushed soft or hard.

Trying to rectify configurations with exsisting, can be challenging,
if it doesn't work. However, gutting what Greg says is essential.

Planning is the key. Are the preamp tubes close proximty to the
trannys. If pots are required, install them first. If the chassis
panel look butchered. copy a metel plate to cover up. Make sure
the 120 cord, has a ground. I find the socket found on PC's are
easy to locate, kinda hard to shape the hole, but they provide a
good chassis entry point. The more you plan the layout, the
easier the build becomes.

Excessve wiring will cause hums that are hard to eleminate.
The filiament ground shound be left as found. However, during debugging
hum, dont be afraid of floating the ground an polk with that node.

The power can capacitor should be ok, leave it intact, they usually
work, especially if project funds are low.