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