When I turn up my master volume to halfway (I keep my channel volumes very low so I can drive the power section with the MV) I get this very computerized stuttering sound for a couple seconds (sometimes more). It happens very easily when I tune down to drop D.

I double-checked everything in the entire amp isolating the preamp, power amp, and cab with other amps in the room so to find what was casuing the problem and everything was fine including different guitars. I'm thinking this is a digital problem/software-related. The software is 2.00 and this stuttering started occurring about 3 months ago after about 2 years of regular use.

Any help here would be highly appreciated--thank you!