1meg vol. pot vs 500K ?

[allsavy]

1meg vol. pot vs 500K ?
Cant readilly buy suitable pots here and need to replace a couple of 1meg volume pots. I have some 500k pots that were intended for guitar. Will these do?
What might be the difference in tone amd or response?

[tubedogsmith]

If you use the 500k pots run a 470k resistor off the wiper. It will slow down the taper a bit but will work fine, you may even like it better.

[allsavy]

cooleo !

[Ronsonic]

Depends on where the pot is in circuit. Usually the value is completely non-critical and the worst that will happen is you might get a little loading on the previous stage. If there are other resistors in series with it or a bright cap across it, it will affect the tone and taper somewhat.

I can't imagine what the added resistor on the wiper is supposed to do. You can very safely omit it. It won't make the next stage work better and won't reduce loading on the previous stage.

[drz400]

1meg vol. pot vs 500K ?
Cant readilly buy suitable pots here and need to replace a couple of 1meg volume pots. I have some 500k pots that were intended for guitar. Will these do?
What might be the difference in tone amd or response?

Dont forget the Reactance from the previous stage.
Ignoring other factors like plate impedance...
If you have a coupling cap at lets say 10n and a Pot of 1 Meg when on 10 you have a reactance of 16hz down 3db.... 8hz down 9db. To maintain the same roll off if you cut the load in half you need to double the capacitance to 22n.

A series resistor going to the grid with no grid resistor directly at the grid will work with the capacitance of the tube and roll off high end. small values are a good thing, large values 100K and higher will change the tone, some prefer some dont.

[novosibir]

If you use the 500k pots run a 470k resistor off the wiper. It will slow down the taper a bit but will work fine, you may even like it better.

... and makes the input of the next stage highly sensitive for catching all kind of noise!

Not a good idea IMO!

Larry

[FUCHSAUDIO]

If the pot is in the circuit after a tonestack (for example) the stack will behave differently. If it's purely a level control, it may work okay, although again, you may need to increase a capacitor value feeding it to retain the bass. Putting resistors on the pot wiper in series adds noise and does not change value. Adding a resistor to ground from the wiper messes up taper and make shte lod on the prior circuit change as the pot is turned up. No free lunches out there folks. Pot values are chosen for a reason....