New Mark V issues!!! Please help. 2 weeks old amp.

[Txhighroller88]

I just purchased a new Mesa Mark V 90 Watt Head and 2x12 Mesa Rec Cab from Strait Music in Austin, Tx. When first brought it home a started playing everything sounded amazing. Then all the sudden a week later I started getting a weird buzzing/distorted sound when playing higher notes in channel 1 and channel 2 (excluding Mark 1). The sound sounds almost like tube buzzing/ringing. Happens in both tube and silicon diodes and all wattage modes. What do you think this could be? I'm hoping to god its just a tube thing because I don't know if I can go 6-8 weeks to wait for a replacement... Thanks everyone!

 

[elvis]

Probably tubes. Only one way to find out. Start swapping in a known good tube. Since it's not in Ch3 I'd rule out PI and power tubes. For now.

 

[Monstercastle]

Yep, probably a microphonic tube. Does it get worse with higher volumes?