Please note! This is a junk item. This item is listed with the assumption that it will be used by someone who is familiar with product functions for repairs or parts replacement. Problems (Failure Status) Noise is mixed into the main output circuit. * In mono/monitor mode, noise is mixed into the mono (main) output. It does not mix into the monitor output. * Noise mixing is particularly bad when the FBQ IN on the main output side is activated. * Other than the above, there are no apparent problems with the operation of the input jacks, knobs, or effects. The above is what is currently known, but I have owned it for over 10 years, and I had the circuit board related to the effects replaced once through Soundhouse, so I feel it may have reached the end of its lifespan. Please consider purchasing if you are interested.