Tube Amp Archive

Is there a rule of thumb to follow when deciding on the bias scheme for your output tubes? I have seen amps built with cathode resistors and caps to provide the bias point and others with negative voltage applied to the grid inputs to achieve the bias point. Adjusting a pot is easy when you re-tube ...

thanks!, bleed resistors that makes a lot more sense.

On the express schematic it looks like R23 and R24 are being used as a shunt regulator to set the B+1 voltage to +395VDC. My question is how much tolerance is there in setting this voltage? I understand that too high would not be good and too low would not be good. So what range of B+1 voltage cover...

Just a little curious, what are D1 - D6 used for?

ND