I bought a Quilter Bass Block 800 to pair with my Markbass 12" cabinet. I tried to get a good sound out of this setup and could not. The sounds I got were "THUMPY, Hollow and rubbery". It only has 4 knobs and I tried all kinds of settings. The only sound that was even partially close to what I wanted (which was the sound you hear in their own demos with their cabs) was maxxing the Gain out. (yes I was plugged into the Passive input BTW), not my first rodeo) I was running a Lakland DJ4 bass, which sounds great through my Hartke KB12. I guess I was expecting the great tones you hear in the demo where it is running with their Quilter 12" cabs, to really here my Laklands tone sing out. But it sounded NOTHING like that. It sounded like the cheapest combo amp you could buy. Oh well. YMMV. Guess you got to buy their cab to get the good sounds.