Marshall 2555X - The Resurrection

[FourT6and2]

Thank you for your consideration and input. Please see my response to Exo detailing the fix. I'll work on getting some sound clips up this weekend as I get familiar with the amp.

Nice, glad you got it sorted haha! Well... we knew it was a voltage/current supply issue... just didn't know it was coming from outside the amp haha

 

[harddriver]

OK, this is mildly embarrassing, but, yes I did solve it. It's weird how, once you're in problem solving mode, the subconscious is constantly working on it in the back ground. I had an idea pop in to my head last night while at work. Is everyone familiar with a current limiter?
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It's a great little device for new-build initial start-ups preventing short circuits from running away and burning up components or blowing fuses because it will absorb excessive current. What it is not great for, apparently, is continuing to use it while doing voltage checks and setting Bias because...newsflash, it limits current. This was the source of my voltage drop. This morning I plugged directly into the wall out let and hurried up and checked my Bias. It was smoking hot at 149ma per pair. After I quickly adjusted that down to 70ma per pair, I flipped it over to check the B+ voltage. Its is now sitting at a nice and healthy 464vdc at each power tube pin3.

What a bonehead mistake. That's how you learn though.

Glad you figured it out. Yeah a good rule of thumb before you even install the power tubes is crank your bias as cold as you can get it. That way you don't zap your new power tubes with alot of current.

So how does the amp sound now?