busted

I've finally taken delivery of my brand new, and eagerly awaited, corvette $$. Pluged it in and all i get are horrible raspy synth sounds. If i pull the volume knob up to bypass the pre-amp it sounds great. Since it sounds fine with the pre-amp bypassed that rules out any problems with my...

My fender rumble 100 is distorted and the sound comes in and out like a bad cable. I have tried 2 different cables and 3 basses and it is definitely the amp. The amp is less than 3 months old but past the 30 day grace period. Is this something I can look at or should I take it in for repair at...