The Blackjack 21 top for Fuchs ODS sounds is built on a 3x 12AX7 preamp. Fuchs Blackjack 21 MkII Mini 1X12 Combo Amp Cover - Black,Tuki (fuchp). Tuki Amp Covers and Speaker Covers (); 99,8% de votos positivos. . It also features an adjustable. They are handcrafted in the same US factory as the larger ODS-Classic and ODS-II. A unique circuit design mixes the wet reverb signal with absolutely no affect on the pure tube dry signal quality in any way.