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RE: Buyig Tubes

Posted by Tre' on August 11, 2021 at 13:36:29:
"Tube amps apparently always present full PS voltage (500v or so?) TO the tube at all times....."

I'm not sure I understand what you mean by that. I'm not sure you understand what you mean by that.

Every amplifier has it's own design. Every amplifier uses the voltages it uses based on the designer.

I designed a single ended 300b amplifier and it uses 465 volts on the plate of the 300b. The 300b is cathode biased and draws 64ma of current at idle. There is 80 volts at the cathode so that means there is 385 volts across the tube (plate to cathode). These details will be different for a different design.

You say the above as if you think that transistor amplifiers don't always present voltage to the transistors. If that's what you think then you are wrong. Transistors run on lower voltages than tubes but the B+ voltage is always presents at the collectors in a SS amp, just as it is (to the plates) in a tube amp.

I hope that helps.

Tre'