1979 Alembic F-2B pre-amp. Works perfect, no scratch in pots, knobs turn smooth. Very transparent and heady. Bridge the channels you get a cool distortion. Bought this from the original owner. Alembic site: 'Another application is to connect the two channels in cascade, by a cable from the Channel A output jack on the rear to the Channel B input jack on the front. The power amplifier is connected to Channel B's output. The signal from Channel A is high enough to drive the first stage of Channel B into distortion. Don't be fooled by the old vintage look, this thing is nice! Comes with rack ears (not attached). $550 shipped. Made a comparison recording while I tested it out. Dry signal first, then with the F2B; on a Fender Jazz fretless.