Hi all,  
First post here! About a year ago I found this Music Man 210 HD One-Thirty in the street a few doors down from my house, and naturally I brought it home. I cleaned it up, gave it new knobs, new tolex, a grill cloth, tubes, the works and brought it to a tech to fix. After ten months, the amp has been returned to me, ostensibly fixed. According to the tech, the amp had been plugged straight into a 240hz socket (I’m in the UK) and the power transformer had more or less melted. One replacement transformer later, and I’ve noticed a few issues with it, and I wanted to run them by the good people here, as my tech doesn’t seem to want to touch it again - see title.

I’ve written down the issues I’ve discovered.  
With nothing plugged in:  
\- The amp hums crazy loud, it must be a ground loop somewhere, I’m running it off of a step down transformer as I’m in the UK and I’m thinking of getting a Morley Hum Exterminator to put in between the power cable and transformer in the hope it’ll kill some of the hum. The hum gets worse the higher the master volume is turned, and I can’t turn the volume pots up past 1 or the hum is deafening. I know 60/50 cycle hum is a thing but when nothing is plugged in to the amp shouldn’t it be silent?  
\- It’s picking up radio like nobody’s business. The footswitch seems to make this worse, but either way it seems to be picking up some local station that plays nothing but reggae all day long. The amp is shielded on the inside above the chassis - I should know, I did it with shielding mesh.  
\- When not picking up radio, the amp hisses with a static sound that gets louder the more the volume pots are turned up.  
\- The tremolo pots (speed and intensity) are modulating the mains hum as if it’s a guitar signal. They also do this to the static sound.  
\- When the reverb pot is turned up it increases the level of mains hum to an insane degree so that the amp is virtually unlistenable. This seems to be helped a bit by plugging in a guitar, but not a lot.  
\- The bright and deep switches change the quality of hum, again as if it’s part of the audio signal.

With a guitar plugged in it’s all virtually the same deal, jumpering the channels seems to do something to mitigate the hum but it knocks out trem and verb.   
\- However, on every note, and I mean every note, except with the MV on really low, there is a fuzz tone - it’s like I’m running an old skool fuzz box into it with the clean tone in parallel. It’s killing the sustain and it’s very digital sounding. The amp is a hundred and thirty watts, it should be super clean, so why is it doing this?

I’ve asked the same tech but his response was “it’s an old amp”. Having had it for ten months, you would think these issues would’ve been addressed. All of the issues are the same on Lo and Hi power, the ground switch does nothing as I’m using a three pronged plug, and the tubes were all replaced (with EHX tubes) before repair - it’s an old 1978 model with the 12AX7 PI tube.

Does anyone have any advice? Should I just accept that it’s an old amp and it’ll have its quirks, or do I have to just accept that my tech did only half a job, and take it to a different tech. Sorry for the long post! Thanks everyone!

The Music Man From Hell - Help Request!