stevem Messages: 4733 Registered: June 2004 Location: NY
Senior Member
You might want to confirm that the amps driver and output stage are ok by pulling signal off of the module jack and feeding it into another amp.
If need be you can replace the 14 pin chip with two LM1458 chips on separate 8 pin sockets.
Note that these amps made after 1972 had tons of gain so as posted above you may just be clipping the input FET.
These amps bo not even need 90 milvolts of signal to be driven to full output.