It's my McAdam Tester Model 2000. Works, as far as I can tell. I think you
can see what it does from reading the controls: it's a power supply, a
signal generator, and a distortion analyzer, allowing up to four units to be
compared at one time.

All the rage for the well-heeled audiophile or service department in the
early '70s!

Still wondering if anyone has come across any documentation for it.

I'm also in a postiion where it looks like selling it is the way to go...