06-12-2019, 11:55 PM
(06-12-2019, 04:01 PM)robert the violinist Wrote: When i had the chassis out i intended to measure the voltage drop across the cathode resistor and the actual resistance of it but not sure which is the exact resistor .
A Google search (other search engines are available) for 6V6 data would bring up lots of sites with data sheets for the valve you specify in your search - 6V6 in this case obviously!
From this result you can see that the cathode pin (shown by a 'k' in this instance) is pin 8. The resistor should be wired from pin 8 to ground. You say you measured the voltage at the cathode pin as 20.9V
As for the value, you may need to know the resistor colour code.
Obviously, if you have the service information for your amplifier, it should show the value.
You mention a 'bias pot' connected to the cathode pin. Without sight of the circuit of your amplifier it is impossible to comment on why it is there or what its function is.
