BBE BMAX-T Groove Tube Bass Guitar Preamp with Full-Featured Sonic Maximizer Full Function 4th Generation BBE Sonic Maximizer processor All tube Class A front-end with interactive 3-band EQ and interactive bright switch Hand-selected premium quality Groove Tubes 12AX7 Jensen transformer balanced DI output Quasi-parametric mid-range EQ with 12db of boost or cut between 250 to 1000hz