Fender Twin Rever MV hum (PLEASE HELP)

[VauxhallandNick]

Hey there everyone. I've got a late 70's MV twin 135 watt. I'm not sure if it's always done this or it's the tiny room I've been practicing in lately or what but I noticed that my amp has a pretty loud hissing/hum sound when plugged into my guitar and turned up to about 3. Master volume at 10. Regardless if im bypassing the signal with my tuner. If no cable is plugged in the hum is fine. But if it's plugged into my guitar it's way loud when I'm not playing. Wondering if this is normal or if there is a way to fix it.

Please help I leave for tour in 3 days and really need this in tip top shape. Aside from that the amp sounds and works fine.

Thanks.

-Nick

[rfurtkamp]

Does it do this with another guitar? With the volume rolled off to 0 on the guitar?

Realistically what you're talking about doesn't seem unrealistic: big, very loud amp, small room, noise when plugged in at idle especially if it's single coils.

[dubkitty]

he's right, you know. trying different cables from the guitar to the amp/board and/or from the board to the amp might help.