I believe this is an old model, the type you often see in studios. Unfortunately, several of the fader knobs on the graphic EQ are damaged, but they can still be adjusted by touching them with your fingernail. The master knob is also missing. Despite this condition, there is some crackling, but the sound quality is impressive, feeling more suitable for an Ampeg SVT than the amps usually found in studios. I was planning to repair it and use it, but I've had to downsize and decided to sell it. This amp can be used as is, or it can be used as a repair project for those who can fix the graphic EQ. I'm selling it at a bargain price, so don't miss this opportunity.