Discharge all your caps before messing with the amp. Double check the values of the 3 resistors between the bias pot and the bias test points. Double check the wiring on the bias pot. And triple check the wiring on the psu. If you're not sure about any of this stuff ask Nik.

FWIW my amp hits 35 mv with the pot right in the center of it's travel.

after 1 day burn in and play.....
i find something that i am confuse.
and i search the forum and a lots topic,and still don't understand.

1.does "presence" not make the tone big different??
i mean when i turn up to max or down to mini.
it does have something different,but i really feel it's not only just this level of different.
i use ethous pedal before,it's presence on poweramp really has a big effect to tone(maybe not advantage)
but i just wonder about this.


2. od eq don't has effective range,i know alots topics have tolk about this.
But when i turn off mid boost and pab boost.
od gain on 8.master volume on 3,i tweak these 3 pot and i have to really really listen carefully that maybe
can heard a little different.

sorry i never use d-like amp,so will feel confuse about this.
But the most lucky thing is that even have these two things.
It 's tone is still amazing.

The presence knob is a very subtle effect, as Gregg mentions. And it's almost impossible to wire incorrectly, so I'd assume it's working. I hear more differences with mine if I use a clean, chimey fendery setting in the clean channel, but again, it's only small differences - I just set mine in the middle.

You'll probably want to check the settings on the internal tone settings before worrying about how the external tone knobs are working - at least with my BM kit the trimmers came pre-set in a strange wonky setting that had the same effect as what you're reporting. Set the trimmers to the settings that are in the users manual first, and then go from there.