SAE (Scientific Audio Electronics) Mark 1 preamp, equalizer. 

This unit has no pots other than the center channel pot on the back, which is dead quiet for those wanting to use a center channel.  Instead, it uses very costly and elaborate step attenuators.

 

Unit has separate left and right equalizer settings to set center frequency and adjust gain, 3 position output gain selector, input for 2 turntables and a headphone jack.

The previous owner though it was a good idea to scribe his drivers license in the side, back and on the inside of the top cover. I heard he had to sell this due to losing everything to identity theft :(   Other than that, it's pretty clean.

See video for operation of all the controls.

Serial # 21451