via this auction
"Quad Includes: MINI; S.E.M.; 303; 2600 Filters ($399.00 if purchased separately).
Fully discrete VCA and OSC 1 sine wave generation
All the features of the original ATC-X. New...Sine Wave generator on OSC 1. Also switchable amp... choose between ATC-X amp or classic Moog amp. New look and as always, same Studo Electronics audio quality."