For me, it's my roland JC-120. It has a lot of hiss, and I never use it. Plus, it weighs more than a marine mammal. I could have bought a nice used low watt tube combo for what I paid for it, and I regret buying it. I started with a Roland Cube 30 when I was a kid, and thought it would be a useful studio tool, but it doesn't work very well with most od pedals, being that it is solid state.
Any amp purchases you regret?
Any amp purchases you regret?