burnedfingers wrote:-----------------I wouldn't, but, Bob Latino would say otherwise...
Most of us will throw in a switch that isn't rated for the voltage it is seeing.
That is the main reason I do not recommend flipping the switch when the amp is running. That and the possibility of arching the contacts and the nasty pop thru the speakers.
If Bob wants to flip his switch let him but I surely wouldn't recommend to amyone to do it.
Just to clarify something > The switches that I use cause no transient spike when switched. There is no transient "pop" when the switch is thrown. I do caution customers to lower the volume level when switching from pentode to triode or vice versa but with the switches that I use there is no need to shut the amp off when making the switch (in either direction).
I also want to disagree with you on the bias voltage when switching from pentode to triode mode (or vice versa). What dcgillespie says above is correct. When you go from pentode to triode (at least on a Dynaco amp) the bias voltage WILL drop very slightly and insignificantly. On an amp with a triode/pentode switch if you are at 55 milliamps in pentode and switch to triode the bias voltage will drop about 2 millivolts to maybe 53 milliamps.
Bob Latino