140906 Phase Linear Speaker Protection Circuit 

This is part 2b, 2a was concerned with the series test circuit used at the end of the installation of the speaker protection relay circuit.
This same modification can be performed on the Phase Linear 700 series amplifiers.
The installation was simple and straightforward, those of you attempting this modification to your PL400 or PL700 power amplifiers should have some rudimentary experience with soldering and circuitry. This was easily accomplished, but not for absolute beginners.