Haze 15 - Noise

[DrewV]

Hi All, My friend brought over a Haze 15 head. The head sounds great withe exception of a low level buzz, similiar to 60hz hum. The noise is there with all controls zeroed out but increases in level with the treble control full open and also when the "effect depth" or "reverb level " pots are engaged. The sound is quite audible. Tried swapping preamp tubes around which made no difference. Any help appreciated. Thanks DrewV

[Jazz P Bass]

Try turning the Reverb & the Effect controls full off.
A 'click' should be heard in the amp.
That click is the Effects Relay turning off, which will totally bypass the digital effects.

[DrewV]

Jazz- Yeah, I've tried that. The noise is still there. Engaging the fx amplifies the noise level slightly. The noise is similar to a transistor motorboating. I'm thinking something in the power supply. Thanks Drew

[Jazz P Bass]

If the FX amplifies the noise, then it is either global (as you said, power supply) or it is before the FX circuit.
What is the full model of the amp?

[DrewV]

Marshall Haze 15

[Jazz P Bass]

Possibly the MHZ15?

[DrewV]

Yeah, that's the one. I'm going to put it back on the bench and have another look inside. The schematic will def help. thanks. The amps I've checked out on youtube don't appear to be making this noise.