This is a two-channel tub/ solid-state hybrid bass preamp with pre- and post-gain controls on each channel. You can use the blend control to mix the tube (a 12AX7 low, mid and high EQ controls with punch switches) and solid-state channels (7-band graphic equalizer, active low and high shelfing EQs) via footswitchable channel select/ combine. Crossover variable from 100 Hz to 1 kHz with frequency and balance controlsFootswitchable post EQ effects loopFull-range, high & low frequency outputsFrequency-compensated balanced & unbalanced direct out with pre-/post-EQ switchSingle rack spaceInternal power supply (no wall wart)