my local guitar tech f***ed it up

  • Thread starter Thread starter kartikbala
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kartikbala

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Send my fender p-bass for repotting etc but he totalled fucked it up, using unshielded wires and old corroding pots....the bastard....

ok sorry for the rant and expletives. :)

now im doing it on my own, so i need some help. what gauge wires shld i use and anyone has any idea of the resistor values of the pots? i think 250K log for the volume and tone rite? any help will be greatly appreciated!

thanks dudes!

kartik
 
check out guitar nuts.com or other sites for info and diagrams. Wire gauge is not critical since they are very short and low current, I would use 20 gauge stranded. 250k is, I believe, the original value used by Fender and other manufacturers for single coil instuments and 500k for humbuckers although a lot of guys including myself use 500k in single coil guitars for the volume pot; they don't kill the highs as much as you roll down the volume. I am not sure if log is the same as audio taper, but I would suggest you get the pots at a music store, they should have the right kind in stock of decent quality. Don't get your pots from Radio Shack. While you are at it you might want to shield the cavity if its not already to further reduce noise. I lined it with aluminum foil and soldered a wire to it, soldered at the other end to the case of the volume pot(ground). If the underside of your pickguard is not shielded, do that too. You can also buy conductive paint (at Radio Shack, I think), you will need to connect it electrically somehow to the ground of the guitar.
 
OK, I feel stupid...I didn't notice you are in Singapore. You probably don't have Radio Shack Stores there? Anyway, try to get some decent quality pots, the cheapies just don't last and will get crackly sounding. Music stores should have exactly what you need ...
 
thank you major tom sir! :)

pots are no problem. i bulk ordered from mouser a while back since im also into DIY amp making.

well lemme try what you advised! thanks a lot dude!

kartik
 
I agree with Major Tom, one thing to add tho' I have used 250k pots on humbuckers and been really pleased with the results, so much so that I would go for that configuration again, The precision is a humbucker machine, and with the shielding try www.guitarnuts.com they have a very good section on shielding.
Clive
 
thanks for all the help so far friends, i tried following the schems for the p-bass but somehow i think i screwed things up.

somehow, with the volume pot at zero, the tone pot can be used to control volume! but if the volume pot is anything more than zero the tone pot has no effect at all....

what is da problem here...anyone got any idea? thanks!

cheers!
 
Hey Andrés,

thanks man.....this really helps....now i actually have an official circuit diagram to follow! :)

cheers!
 
I've got another qn...forgive my ignorance.

The circuit diagrams recommend 250K audio taper pots. Does anyone know what will happen if i use 250K linear taper pots. How about if I use 500K audio taper pots? Will the frequency range change...etcetc???

Thanks a lot for ur help!

Cheers!
KB
 
The "taper" on pots,linear vs log is like this,for example on a volume pot...
Linear is a straight line from 1 - 10.At "3",it is 3X louder than 1."5" is 5 times louder etc.
On the log scale,all the action is at the top,from about 6-10 is where all the volume is happening.Just like your ear has a log curve for volume sensativity,you should use potentiometers with a log curve to the taper.That is what is stock on most axes.
 
The linear taper pot will work, but as you rotate it part of the adjustment range will not seem to do much, and part will seem too touchy. You will NOT be happy with it. The Audio taper pots are engineered for audio volume adjustment - any kind of audio volume adjustment whether on an amp or guitar or TV set is not a LINEAR scale. For a volume to seem twice as loud, the power has to be quadrupled, it is this ratio that has to be engineered into the pot so that it SEEMS linear in operation.

The difference between 250 and 500k pots is pretty subtle, I'm not sure if you could hear much difference...if you like a real bright tone, go with the 500k, if you roll off treble anyway, use the 250k. In practical application the 500k should have a little extra brilliance available; you can always turn down a treble control on the amp or use the tone control on the bass (or guitar) if it is too bright, but you can't add in that little bit of brilliance that was lost with the 250k. Volume controls on guitars/basses act a little like a tone control ; when you turn them down; the sound loses a little high end. I think the advantage of the 500k (and where you will HEAR the difference the most) is that it acts less like a tone control than the 250k as you roll the volume down...
 
Major Tom said:
Volume controls on guitars/basses act a little like a tone control ; when you turn them down; the sound loses a little high end. I think the advantage of the 500k (and where you will HEAR the difference the most) is that it acts less like a tone control than the 250k as you roll the volume down...
Click to expand...

Not all 250k volume pots roll off the treble, just the cheapo ones. The stock volume pot on my old guitar was very tiny, and it rolled off a LOT of treble as I turned it down. The replacement pot was almost twice the size and rolled off so little treble that you couln't hear it unless you really tried. The replacement sounded cleaner and brighter at any setting. So basically, when buying new pots, buy GOOD ones. Don't skimp because they can really affect your tone.
 
Hi dudes,

Thanks for all your help/comments. The thing is I realised that I only have 250K linear pots with me(generally used for the treble on amps), but have loads of 500K audio pots. So that's why the question abt the 500K pots.

Maybe I'll just try it out with the 500K pots for both tone and volemu and see what the results are and post it here!

Cheers!
KB
 
Another qn for the guitar wiring blokes out there...

For a P-bass, does it matter which pickup goes to the neck and which is the bridge pickup? My guitar tech replaced the wires with all red coloured ones so I can identify squat! :)

Can I measure some resistance value or anything of that sort?

Thanks for all ur help so far...

Kartik
 
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