• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Carbon Film Resistor for plate load?

Try both. You'll spend more on your time than you'll spend in resistors.

Reading thru Building High Fidelity Valve Preamps will give you the idea that Hi-Fi projects should use Metal Film, while guitar projects should use Carbon Film.

Posts on this forum could give you the idea that Grid Leaks and Grid Stoppers should be CF, while Plate Loads should be Carbon Comp, and resistors in the power supply should be Metal Oxide.

All that's to say, you can find an argument for any resistor in any position. Only your ears know what sounds right to you.
 
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Plate load resistors can be any resistor you want. Are some better in a plate load than others? Yes. Carbon film and metal film are nearly the same price nowadays, so most people use metal film. A good brand/series is Vishay PR0 series.

Carbon composition resistors are noisier than film resistors, but your circuit has to be quiet enough to hear the noise contribution of the resistor. Most amp circuits will work well with carbon comp.

Check out Digikey and Mouser for the PR0 series.
 
Try both. You'll spend more on your time than you'll spend in resistors.

Reading thru Building High Fidelity Valve Preamps will give you the idea that Hi-Fi projects should use Metal Film, while guitar projects should use Carbon Film.

Posts on this forum could give you the idea that Grid Leaks and Grid Stoppers should be CF, while Plate Loads should be Carbon Comp, and resistors in the power supply should be Metal Oxide.

All that's to say, you can find an argument for any resistor in any position. Only your ears know what sounds right to you.
What about cathode resistor? What type then?
 
No need. Power tube cathode resistors work hard, everything else can be 1/2w. High gain guitar amps may benefit from 1w plate load resistors, but 1w carbon comps are getting hard to find.

e cathode resistor is a perfect place to use ohm's law to determine the current thru the tube, and the K resistor.
 
okay, carbon comp is the best choice for plate load and non inductive wirewound for cathode bias.
Remember, a Hi-Fi amp's job is to faithfully reproduce a recorded audio signal. A guitar amp's job is to take a guitar signal and make it more. Carbon Comp resistors add something to the sauce in a Guitar amp. MF and CF resistors will behave better in a Hi-Fi amp, or preamp.