Is anyone familiar with the process to bias the TRL Dude Preamp

I only checked when I replaced Sprague electrolytics for MR Clarity film caps, same procedure though.

I have a 2nd generation Dude (liked looks better, no big deal)

The pot actually sets voltage for the power supply section overall, not any particular tube bias.

The preamp should be FULLY WARM, for a steady meter read.

Set voltmeter for proper DC range.

Voltmeter RED probe/clip goes to first cap on right bank (POSITIVE +)

BLACK probe/clip to (STAR GROUND-) usually the last cap towards rear of preamp, you’ll see the wires bunched together.

Do this carefully and slowly, the voltages can be you-know-what.

If you don't feel safe or sure, have a tech do it.

335VDC is where mine’s at, there will be a plus-minus 5 volt swing or so during your dial-in, that is normal, the trim pot is sensitive, as long as it’s in that range your good.