Peltor:
If you turn the amp On and just leave it On for an hour, without playing any music, and you place your hand on the top of it- place your hand on the red part of the cover- does it feel very warm- close to hot so that its almost uncomfortable to keep your hand on it? If so, then you probably need to lower the bias current.
The BA-5000 service manual has an explanation on the procedure to do this. Basically, what you do is remove the red cover and there are two wires that need to be removed from the power supply section- one on each side, left & right. You need a meter that measures current- the meter leads will go to a test point (as shown in the svce manual and the photo I posted)and attaches to the power supply wire. (positive red lead to wire, neg black lead to test point) The BA-5000 must be connected to 8 ohm speakers. Turn the power on and after about 3 to 5 minutes- see what the current reading is on your meter- use a setting like 200Ma on the meter- or set it to the highest current reading and move the meter setting knob down until you get a good measurement. The normal level is 180mA for the BA-5000 +- 1 mA. If your amp is running hot, you will get a reading much higher than that like mine was: over 350Ma. There is an adjustment pot that you can turn- you need a tweaking tool- something like the tip of a flat blade screwdriver- when you turn the adjustment pot- you can lower the bias current to 180mA. You then do the same thing on the other side- measure the bias current and adjust the pot on the right side if the reading is too high. Or if you have two meters- you can measure both at the same time.