Replacing old pots

[DeadSpeaker]

I have a friend with an amp from the 60's. When the volume pot is turned, the volume of the amp seems to jump from very quite to very loud at about the 3 to 4 positions and then get a little loud as it is maxed out. I think that it should behave less jumpy. Here is the schematic. http://www.gibson.com/Files/schematics/G20A, G30A.pdf

Can I replace the pots with 1/2 watt ones or do they have to be 1watt?

 

[Mooly]

Hi, You can replace with whatever will phsically fit. Wattage does not come into it here. Use a pot with an audio or logarithmic taper for volume, if replacing bass/treble pots these must be linear.
Regards Karl

 

[djk]

The bass/treble pots are also log taper.

 

[Mooly]

Oop's , Absolutely right djk, it's just a passive Baxandall network.
Regards Karl

 

[DeadSpeaker]

Thanks guys. Would a different resistance on the volume pot make it less jumpy?

 

[Mooly]

Hi, You need a 47 or 50 k pot, value is important in this case as it works with the other components around it to determine the characteristics/response curve of the tone controls. It is a common value. the jumpiness is caused by either wear or dirt on the carbon track.
Karl

 

[michigannick]

Tossing in 2 cents .. modern multi turns can make a nice difference too if you are looking for really make things granular. but it can make figuring the middle a bit difficult