Dismiss Notice

Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

Pots, 250k, 500k ?

Discussion in 'Pickups & Electronics [BG]' started by centralharbor, Jan 9, 2006.


  1. centralharbor

    centralharbor

    Nov 21, 2005
    hawaii
    So, I searched for the answer, but I couldn't find anything, so here it is. What's the difference between these pots? How does it change the sound? If I have one kind of pot on my bass, could I change them for the other one? Is there anything else that I should know about the different kinds of pots?
     
  2. Rodent

    Rodent Supporting Member Commercial User

    Dec 20, 2004
    Upper Left Corner (Seattle)
    Player-Builder-Founder: Regenerate Guitar Works
    from the content of your post, I assume you're running a passive bass. yes?

    If you're running an active pre-amp in your bass, the optimal pot values will be determined by the pre-amp manufacturer.

    Even more important than 250K vs 500K is to know the taper type enacted when you turn the knob. There are type types: audio and linear. Audio is a log taper, and is in-line with how your hears differences. The linear taper is exactly that - and even distribution of change thru the entire turn range.

    Most people hear a linear taper pot as having all of its range loaded into 10% of the turn angle at one end of the range. Likewise they hear an audio taper pot as having an even effect the entire turning range of the pot.

    All the best,

    R
     
  3. Greg Clinkingbeard

    Greg Clinkingbeard

    Apr 4, 2005
    Kansas City area
    Setup and repair/KRUTZ Strings
    500K pots may give a bass a bit more output and make the sound a tad brighter. They are better with dual coil pickups like Barts. For single coil, 250 are better.
    If you have a passive bass you can change your pots with no danger, assuming you know how to solder. ;)
     
  4. Hollow Man

    Hollow Man Supporting Member

    Apr 28, 2003
    Springfield, VA
    Would you mind characterizing what makes the 250k pots 'better' for single coils? I've heard that the 500k pots tend to let a little more high end through, but I don't know of any other advantages/disadvantages to one pot value over the other. Are you meaning to imply that a 500k pot with a single coil pickup would just be too much treble?
     
  5. Slater

    Slater Bye Millen! Hello?

    Apr 17, 2000
    The Great Lakes State
    Higher pot values allow for brighter sound. A 500k pot will allow your pickup(s) to sound brighter than a 250k pot.

    Generally, 500k pots are used with humbucking pickups (because they're not a bright a single-coils), and 250k pots are used with single-coil pickups (because single-coils can sound harsh with higher value pots).

    But, there are no rules. Through trial and error you can use what sounds best to you.

    With active electronics, I would suggest using pot values recommended by the manufacturer.
     
  6. Greg Clinkingbeard

    Greg Clinkingbeard

    Apr 4, 2005
    Kansas City area
    Setup and repair/KRUTZ Strings
    I remember reading somewhere that Jaco put 500K pots in the 'bass of doom' to give it the harmonically rich sound it is known for. That bass was pretty bright also. If it is true, it is the only single coil bass I know of with 500K.
     
  7. centralharbor

    centralharbor

    Nov 21, 2005
    hawaii

    Sorry but you lost me there. Are you saying that audio pots are better than linear pots because their change is more evenly distributed through the whole turn?

    Yes I do have a passive bass (its a p-bass).
     
  8. ehque

    ehque

    Jan 8, 2006
    Singapore
    better is a matter of opinion. most people prefer a even change along the full turn so they can tweak the signal better.

    linear pots tend to go into tone controls. if audio-taper pots are used here, you get the reverse problem, also resulting in only a small angle of knob responsible for a very wide range of change in sound.
     
  9. centralharbor

    centralharbor

    Nov 21, 2005
    hawaii

    whats the reverse problem?
     
  10. Bass2x

    Bass2x

    Jul 25, 2005
    SoNJ
    Just had a master volume pot wired into my fretless Warmoth custom J bass. But all the volume is in the last 10% of travel. The luthier said it was an audio taper pot. Swapped out the 250k for a 500k with same results. What's the problem?
     
  11. klocwerk

    klocwerk

    May 19, 2005
    Somerville, MA
    Could be that the electronics in your bass are compensating for the log curve of the pot, and expecting a linear pot.
     
  12. Bass2x

    Bass2x

    Jul 25, 2005
    SoNJ
    You may have hit on something there, klocwerk...
    The bass used to have active electronics (Sadowski preamp) and was converted to passive (w/Aero pups) before I got it. I wonder if this has anything to do with the problem?
     
  13. Bass.

    Bass. Supporting Member

    Jan 23, 2006
    San Diego
    if a bass hase one single coil jazz pickup and a humbucker could a 250K pot be used for the jazz and a 500K for the humbucker or do they need to be the same value?
     
  14. Yes, you can mix and match values in the same instrument. Many times I have built Les Paul harnesses for customers that have requested 500k on the neck pickup and 1 Meg on the bridge with wonderful results.

    ~Stan
     
  15. epoxo57

    epoxo57

    Feb 17, 2005
    Perrysburg, Ohio
    Great thread! I had the same question for my Warwick Corvette that I want to retry my Dimarzio J's in (have EMG's in currently). I originally took them out because they had a buzz problem until I put my hand on the strings. I had them wired to the original Warwick harness (passive). I can't remember what the exact pot values are, but I thought trying 500K pots instead may cure the problem this time. I liked the killer tone, just not the buzz. I made sure the ground from the bridge was connected (will have to reconnect). The EMG's may be a bit bright...but yet..I knew they were already going into it.......:rolleyes:

    My question: Which pot would suit the Warwick (bubinga body, ovankol neck, wenge fb) with the humbucker J's? 500K seems recommended? Or stay 250K like the norm? Maybe I'll just play with both since those solder fumes are highly contagious :D

    Thanks!
    Scott
     
  16. murphy

    murphy

    May 5, 2004
    Toronto, Canada
    The Lakland JO5 has 500k pots.
    It is definately brighter sounding than my bass with 250k pots which have more low mid emphasis with the same type of Fralin pickups
     
  17. The Dave

    The Dave

    Jun 23, 2006
    Canyon, Texas
    I put some Model Js in my Jazz and kept the original 250k pots at first. It did sound a little dark but that could also be attributed to the strings I was using (D'Addario Half Rounds). So, I switched back to Fender Rounds and wired up a 500k pickup blend pot with the original 250ks for master volume and tone. I'm thinking I'll probably go ahead and replace those with 500k also for some more clarity and cut but I haven't gotten around to it yet. I'll probably add a lower value tone capacitor too so that I can roll off those extra highs without adding a lot of bass.
    Here's a good idea if you're going to be trying different pups and pots: Open up your bass and snip the pup leads near the pots. Then attach some kind of connectors to the ends so that you can just plug them in. Once that's done, you can wire up a set of 500k pots, solder on a short piece of wire with a connector and you can switch your pots and pups any time you want. I'm going to order a couple of extra control plates and wire up a couple of different setups for my Jazz. I'll post some pics or something.

    Sorry for the long post. :(
     
  18. RyreInc

    RyreInc

    May 11, 2006
    Kalamazoo, MI
    In the design I'm pondering for my g**tar I will have all 500k pots, and the volume pot will be a push/pull to add a resistor in parallel to the output for lower resistance.

    This way you can have the best of both worlds! :bassist:
     
  19. alibloke

    alibloke

    Dec 17, 2004
    Bristol, England