Hammond Tone Cabinet PR40 "line in"?

[spy]

I'm servicing a Hammond PR40 (recapping, retubing, etc.) and I'm wondering if I can have a "line in" and use it with other stuff except the B3. Here's the schematic of PR40, http://captain-foldback.com/Hammond_...R40_QR40_1.gif.

G1 and G2 is the input and it's a balanced input, right?

Here's the schematic of the preamp stage of B3, http://captain-foldback.com/Hammond_...atics/ao28.jpg, you can see the output transformer after 12BH7.

Do I need an unbalanced to balanced transformer? Or I can connect an unbalanced signal to G1-G2?

[Brad1]

Hammond PR40 revisited....

I'm servicing a Hammond PR40 (recapping, retubing, etc.) and I'm wondering if I can have a "line in" and use it with other stuff except the B3. Here's the schematic of PR40, http://captain-foldback.com/Hammond_...R40_QR40_1.gif.

G1 and G2 is the input and it's a balanced input, right?

Here's the schematic of the preamp stage of B3, http://captain-foldback.com/Hammond_...atics/ao28.jpg, you can see the output transformer after 12BH7.

Do I need an unbalanced to balanced transformer? Or I can connect an unbalanced signal to G1-G2?

I was just given one of those things, in excellent condition. It works, it's fairly "self-noise quiet", and it will pass a signal through a preamp jiggered up to it...just not as beefy as I know it should be. The old Jensens are even still crisp, tight and non-faded.

I know it takes more input signal than the average guitar/studio preamp might give to get it barking (I tried several things).

Any ideas on options to use with guitar? Minor changes in the input? Build a bigger preamp? Some of both? Gut the thing and use the speakers for something else, and the amp for something? Try to sell it to a Hammond guy?

What DID come out of it was pretty cool. It filled the room with sound, with that top-firing speaker.

Thanks,

Brad1

[Diablo]

I just bought a working PR40 to gut it for the speakers, tubes and iron. I feel a little guilty, but maybe it's like a heart transplant. Someone or something will live on.

[Rhodesplyr]

Hammond wisely decided on a fairly hot, balanced line signal connection from the organs to the tone cabinets to keep noise low, so, as others have posted, it takes a hotter signal than normal line level to drive a PR-40 (or a Leslie 122) to full output.

There is an RCA jack on the swell capacitor housing of the B-3 preamp you can use to input a line-level unbalanced signal into the organ. It will come out the PR-40 just fine.