I have a couple of 1224A's in good working condition in A-7's with 421's, 511B's, 808A's. I would like to have a users manual for these Bi-amplifiers, and any advice from anyone on how to use them properly. I've had some fun with them and have renovated them per Jim Dickensons recommendations. They appear to have some decent low end, but I'm wondering if they really go down as low as 35 hz like a sub. I'm gearing up to use them in a band application...Thanks....Kevin