What I am finding with the Overtone is with the OD trimmer set to anything past 9 oclock the amp gets a little too bright with the PAB engaged and since the tonestack is lifted there is no way to dial it out. It makes for great Marshall bite but I'm persistant to getting Larry and Robben Dumble tones. Time for tweaking.
A quote from ChrisL...
You'll never know until you open up the amp and tweak that trimmer.