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Explain resistance in pots

Discussion in 'Pickups & Electronics [BG]' started by bassontherun, Jul 9, 2005.


  1. bassontherun

    bassontherun

    Jul 9, 2005
    After playing stock basses for several years, I'm going to try my hand at putting together a rig with aftermarket hardware. Looking for some insight on resistance of the volume and tone pots, and if/how various resistance (100, 250 500, etc) will change my tone/output. As well, I noticed a resistor (?) between the tone and a volume pot (P/J P-ups with one tone and two volume pots in a low-end Ibanez). I'm assuming that this resistor will need to be changed if I go to pots with a different resistance than stock. If it makes a difference, I plan to load a set of P/J Quarter Pounds in the bass. Thanks for any enlightenment!
     
  2. dave120

    dave120

    Jun 27, 2005
    Central Florida
    500K pots will give you a brighter sound and lower value pots will give a deeper, warmer sound. The higher the value of the pots, the less load there is on the pickups which means less treble frequencies will be lost.

    Essentially, I think most basses probably use 250k pots (at least the ones I've had) because generally a bass wants more of a warm tone than a bright twangy one.

    What you think is a resistor is most likely a capacitor. The higher the value of this you use, the deeper your sound will be with the tone pot at minimum because it will reduce highs by a larger amount. Using a small value capacitor will only get rid of super high frequencies, which basses usually don't have much of anyways.
     
  3. bassontherun

    bassontherun

    Jul 9, 2005
    Outstanding! Although I'm looking for the high output of the Quarter Pounders, this bass is being set up for a thumpin' P-Bass tone (also looking at the Rotosound Steve Harris flatwounds). Sounds like I want to go for pots that are 250K or less. Does anyone (Dave included) have any thoughts as to the lowest usable resistance at the pots? I saw another thread that discussed 25K pots, but wasn't sure if that was appropriate for this application(?).

    If I read you correctly, the capacitor functions somewhat independently of the pots, and can be used with any pot resistance. If this is not the case, please correct me.

    Thanks again for the assist!
     
  4. dave120

    dave120

    Jun 27, 2005
    Central Florida
    Yes you can use any value cap with any value pot as far as I know. But the value of the capacitor only affects what the sound will be with the tone knob turned down. With the tone knob on full it makes no difference which one you're using, whereas the pots will make a difference in any setting I believe.

    When I re-wired one of my Washburns I used 250k pots and a .047 cap with my Hot for P bass pickup. Works pretty well and you get a wide range of tones out of it. You can get 25k and 50k pots, but I've never used them so I can't comment on how they work.
     
  5. Alex Wing

    Alex Wing

    Apr 1, 2005
    Boston, MA
    The 25k pots are generally recommended for active pickups.
     
  6. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    25K pots are for active pickups, I wouldn't advise using less than 250K for passive. You might decide to use 500K on an acoustically dark bass, or 250K for a bright bass.

    If you do a search you'll find SMASH's thread where he did a bunch of different cap value experiments.
     
  7. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    if memory serves me correctly, in the past I've installed 25k pots with passive pups (without an onboard preamp) and it choked volume and tone, making them sound extremely thin with poorly defined frequencies - pretty useless. Nothing uncommon about using 25k with passives with a preamp.

    To be honest, I haven't noticed enough difference between 250 and 500K pots to bother with. I'd guess that if you played a given bass enough, you could tell the difference and one or the other may give you an edge depending on your needs.

    SD it seems has pot recs on their site and I'm inclined to go with manufacturer recs for openers.

    Caps are probably the cheapest and simplest reversible way to alter tone in a major way. Seems it takes a cap value variation of about 10 mfd to really notice a difference. Spreads of about 25 mfd steps +/- seem a good alteration off the rough bass standard of .05 - ie, ballpark .01, .025, .05, .075, .09. if you want to experiment. That's about $10 worth of caps depending on where you get them.
     
  8. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    I've noticed a difference, it's not huge but sometimes that small difference is the difference between liking/not liking.

    I generally like having those highs *available*, because although you can take them away with a tone control you can't add them.
     
  9. bassontherun

    bassontherun

    Jul 9, 2005
    Many thanks to all for the insight!! Decided to go with some 250K pots from AllParts (they had the mini's in 250) and a set of Dimarzio DP126's (MF has them on sale this month). If this setup gives me the more traditional P-Bass sound that I'm after, I'll have completed the project (and a NICE looking bass) for right at $200.
     
  10. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    in my experience it doesn't take any more than that to get a decent playing bass that will put out a sound that's a joy to play. That's about all that I've got in mine at any given moment - depending on what I paid for the pups in it at the time, often it's considerably less than $200.
     
  11. bassontherun

    bassontherun

    Jul 9, 2005
    Couldn't agree more. Back when I was gigging regularly, I used an American P and an American J from Fender, and later a couple of different German Warwicks. Absolutely loved every one of them!

    I've also had a dozen low-end basses (Epi, Yamahas, Samick, MIM/MIJ Fenders, no-names, Rogues, etc.) that have been very suitable. Hate to say it, but one of my best sounding basses to-date has been a Rogue LX405. Kinda wish I had that one back. I actually liked the dry tone better than my OLP MM3. After adding an old Pandora to my OLP, all is well with the world.

    Now that I'm only gigging part-time, I can't see going back to the better mid-level basses (my wife sure likes that part). Lucky for us, music stores like GC and Mars (R.I.P.), and the big on-line retailers are bringing us better quality equipment at outstanding prices. I'm not about say that a Samick sounds like a Sadowsky, BUT for many folks who just want to play music without breaking the bank, the low-end stuff is now very gig-worthy with little modification.