New rockerverb MKIII HUMMING

[peachcake]

I very recently just purchased a new rockerverb MKIII 50 watt along with a 2x12CB. Running into some issues, wondering if its normal. First off, when just having a speaker cable connected to the amp and cab, I can hear a small hum coming from the cabinet. Furthermore, When I have my guitar plugged in, the hum gets louder as the volume is turned up and doesn't go away when I strum the strings or mute the strings. Same thing happens on the dirty channel if not worse.

[Jondog]

It could be a number of things. bad tubes, or electrical interference. Make sure you're not under fluorescent lights and nothing else is plugged into the electrical circuit you're plugged into. A little bit of hum is normal.

[Phlowen]

Hmmm...this easily be a bad tube, a bad transformer, or could just be a transformer that needs broken in (which is a weird idea that I didn't think existed but let me explain). I bought new transformers for my TH30, and after installing them and playing on them for a few hours, they had a bad hum...I told them to a repair place, they put the amp through it's paces, couldn't hear anything. I went and picked it back up from them, sure enough, the hum was gone. My tech said sometimes new transformers just need to work out their kinks. Might be the case with yours, although if this was a common thing you'd be hearing about it a lot more, so it has to be a really rare thing.

As much of a bummer as it is, you just bought it new...return it for a new one!

If you really don't want to do that, try retubing it.

If that fails, just get a new one!

[peachcake]

Yeah I think I'm gonna return it for a new one. As for further diagnosing, it hums when it's just connected from the amp to the cab. Hums louder when the guitar is connected. Gets progressively louder in both clean and dirty channels when I increase volume. Also turning up the reverb has also increased the volume of the hum. However, if I roll off the volume knob to 0, the hum goes away but the initial hum from amp to cabinet can still be heard. I have tried plugging it in several areas of the household. Same issues. Everything goes away if I put it in standby mode though. I also tried to use a HUM X to rule out any grounding issues and the problem still occurs.

[Jondog]

Could just be a tube.