Tone Pot Value

[blown240]

I am building a copy of a 6G6B Bassman.  It calls for a 25k bass pot and a 250k treble pot.  I have a couple extra 500k pots.  Would these work?  What difference will it make?  Sorry if its a stupid question, but I am new at this.

[sluckey]

You could get by with using a 500K for the treble pot, but using a 500K for the bass pot will be almost useless. Just sneeze on the knob and it will travel the 25K value that a 25K pot would travel in 300°. If you want it to sound kinda like a 6G6 you may want to keep the component values in the ballpark.

[blown240]

Ok cool.   Looks like I will be getting a new bass pot.

[RicharD]

http://www.duncanamps.com/tsc/download.html

You can download Duncan's tone stack calculator and see how different values effect the the response of the circuit.  The equation for frequency is 1/2piRC.  To go from a 25k range to a 500k range means you'll have to drastically change the cap in that tone path.  The short answer is, if you're cloning stick with the known values as much as possible.  If you're experimenting either crunch numbers long hand or use the nifty Duncan thang.

[DummyLoad]

I am building a copy of a 6G6B Bassman.  It calls for a 25k bass pot and a 250k treble pot.  I have a couple extra 500k pots.  Would these work?  What difference will it make?  Sorry if its a stupid question, but I am new at this.

install a 27K in parallel with your 500K - now you have a 25K pot.

--DL

[blown240]

Cool thanks. 

I downloaded Duncan amp tools, but i dont see a schematic that looks just like the one I am using.

[DummyLoad]

yes there is; look closer... ;)

[jjasilli]

install a 27K in parallel with your 500K - now you have a 25K pot. --DL

Yes, but not really usable due to the sharp slope of the modded pot:  at full rotation 500K║27K= 26K; but at only 1/10th rotation of the 500k pot:  50K ║27K= 18K.  This is 72% rotation of a 25K pot!  You can't really dial in anything under that.