Tube Amp Archive

I did hear back from their builder. He said KT66’s work well in this amp and ‘typically have a plate voltage of 465’. Clearly, I’m no expert but I have built a handful of amps, and am aware of safety concerns. I was thinking there may be a formula to predict the bias current on tube type C if you ha...

I have a RedPlate Astrodust Duo that I would like to try a pair of KT66's in, but I'm not sure where to set the bias.

The chassis suggests 72MV for 6L6GC and 46MV for 6V6GTA.

Do I need to open the chassis and take measurements to bias this correctly, or can it be inferred from this data?

Thank You!