The explanation holds true for push-pull AB1 amps but the amp in question was single ended. If the single ended operation is anywhere close to class A then there will be hardly any difference between idle dissipation and full signal dissipation so current passing through the resistor would change little if at all.
Also chassis mounted resistors usually require the chassis to be used as a heat sink for their full power rating. The free air rating of many 10 watt chassis mount resistors is around 60% of its full power rating. If you do not have the typical full 130 sq. inches of heatsink for the 10 watt resistor it will need to be derated. Always good to check the specification sheet for the resistor used, and another good reason for overating it.
Also an over-engineered resistor will run cool, and its right next to the cathode bypass capacitor that isn't so happy sitting next to a hot component?
Ok, but then what about a cathode bypass capacitor? since an audio signal is AC, reactance is going to affect and play with the circuit a bit as "two resistors in parallel"
The explanation holds true for push-pull AB1 amps but the amp in question was single ended. If the single ended operation is anywhere close to class A then there will be hardly any difference between idle dissipation and full signal dissipation so current passing through the resistor would change little if at all.
Also chassis mounted resistors usually require the chassis to be used as a heat sink for their full power rating. The free air rating of many 10 watt chassis mount resistors is around 60% of its full power rating. If you do not have the typical full 130 sq. inches of heatsink for the 10 watt resistor it will need to be derated. Always good to check the specification sheet for the resistor used, and another good reason for overating it.
yes please, do a load line video on where to set the point of idle for a tube!
Also an over-engineered resistor will run cool, and its right next to the cathode bypass capacitor that isn't so happy sitting next to a hot component?
consider placement and available space in the chassis when opting for higher watt resistors. sometimes they get large.
Ok, but then what about a cathode bypass capacitor? since an audio signal is AC, reactance is going to affect and play with the circuit a bit as "two resistors in parallel"
Cathode bias resistors can get very hot as they operate. The more wattage the better. Why do you want to hurt your amp, just to save 2 or 3 coins?
Nice!!