Ah, it was a low pass not a high pass.... Memory plays tricks !
How a mono channel can be advertised as a stereo unit is for the seller to explain....
And it's still a silly number when correction and effects units were 2000 series.
It used the same components as the stereo unit I saw, but minus the racking, power supply and second channel.
I still don't recall seeing them.... They may have made a batch C1970, the year before I joined, and then not again.
Posted from my iPhone