You're thinking of Option 06.
On Thu, Sep 12, 2019 at 10:53 AM Ed Breya via Groups.Io <edbreya=
I believe this "option 1" may be to replace the standard trace position
pot with an offset function, kind of like in the 7A13, but only over a
limited range. I vaguely recall that I have one of these, but didn't know
it was different until I started using it - the trace positioning acted
differently, and advantageously for some applications. I haven't seen it in
a while, but I think each channel has dual concentric pots, instead of the
single pot and "ID" button.