Here's my TC Electronic BQ500 in mint condition. I'm selling it for $250 PPF&F plus shipping. These amps have incredible output and a great feature set. The compression works great for a one-knob compressor. The tone centers work well with my active basses! (Which pretty much means ALL my basses -- I don't have any passive basses.) 
It comes in the original box with cord and owner's manual. Here are some specs!
TC Electronic Thrust BQ500 Bass Amplifier Head Features:
It comes in the original box with cord and owner's manual. Here are some specs!TC Electronic Thrust BQ500 Bass Amplifier Head Features:
- 500-watt Class D bass head/DI
- Lightweight and compact
- Fits easily in a backpack or gear bag
- MOSFET preamp unlocks tubelike warmth and touch dynamics
- 4-band EQ scoops and boosts to your every whim
- Simple onboard compressor smooths out performances
- Balanced XLR output with pre-/post-EQ switch feeds your colored or uncolored tone into a PA
- Secure locking speakON speaker out (4 ohms minimum)
- 1/8-inch headphone out plus aux in for silent practice
- Worldwide power switching for interruption-free performance anywhere on the planet
