RCA BA-6A Limiting Amplifier (Compressor)
The RCA BA-6A limiting amp is one of the best. It's really more of a compressor, since the gain is controlled by the audio outout level. This specimen is rather nasty, and so it's going to get a devout cleaning. I have no doubt it will work fine after cleaning and some repairs. The schematic is from www.waltzingbear.com
This unit is planned to go with the Norton amplifier to complete the speech amp for my ham radio AM transmitter.