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Pots, pots, pots.

Discussion in 'Pickups & Electronics [BG]' started by afrodisiak, May 14, 2006.


  1. afrodisiak

    afrodisiak

    Mar 14, 2006
    Singapore
    I'm playing an Essex Jazz and I've been looking to change the pots. However, I know next to nothing about pots and after browsing through allparts.com, my mind is filled with more questions.

    Should I go for 250k or 500k?
    What's the difference between split, knurled and solid pot?
    What are the differences between linear, blend/balance and tone/volume pots?

    As you can see, I know nothing about them pots. I'd gladly appreciate it if anyone could answer my questions here in this forum, but I'd be equally thankful if someone points me to another website or thread where I can read up on pots myself.

    Thanks! :hyper:
     
  2. squidospyder

    squidospyder

    May 6, 2006
    From what little I know about electronics, Log Taper (or also called Audio Taper) is normally used for volume control. These pots will have a 'A' prefix or suffix on the pot eg A250K or 250KA. To simplify things, this kind of pot is supposed to relate more closely to how the human hearing works. When the control is in the halfway position, the Log Taper pot will sound more like a half volume drop than a Linear Taper, which I will mention briefly below. But a small note: it doesn't help that some (cheap) Log/Audio pots aren't really very good at this 'relating to the human hearing' thing. If you're obsessed about it, you can try doing this: http://sound.westhost.com/project01.htm but I think that would be a bit drastic to really bother for most heh.

    The other common type of pot used is the Linear Pot (marked 'B'), commonly used for tone, though it is not uncommon to find Log pots for tone as well. In simple term, linear pots have a linear reistance change in relation to the degree pf the pot's turn. Eg if position 1 = 0 Ohms, position 10 = 500Kohms, position 5 = 250Kohms, position 8 = 400Kohms and so on.

    Small note: bear in mind that active electronics will need to use their own stated types that may not be the same generalisation above with passive electronics (which is your case at the moment). Another note: if you're using lefty bass, you need another type of pot for volume: The reverse taper or reverse log taper pot, with a 'D' marking on it.

    Some stuff below dug up from the net... Maybe others can add on to it


    Taken from the DiMarzio website www.dimarzio.com
    :
    Should I use 250K or 500K controls?

    Regardless of what type of pickups are in your guitar, higher potentiometer resistance values produce a little more power and treble response. Whether this is a good or a bad thing is a matter of individual taste. In the early days, Gibson used 500K controls and Fender used 250K, thereby starting the single-coil = 250K, humbucker = 500K theory. Even though neither company has stuck strictly with this formula since then, the theory lives on. You won’t damage your pickups or your amp by mixing and matching different value controls, and one of our current favorites is a 250K volume control and a 1 Megohm tone control, EP1202.

    Taken from the Stewmac website www.stewmac.com:
    250K vs. 500K
    Generally, 500K-ohm pots are used with humbuckers and 250Ks are used with single-coil pickups. 25K pots are used for active systems.

    You can use any value you like, but a 250K will give a slightly warmer tone than a 500K pot. The 250K pot bleeds off (attenuates) some of the high frequencies to ground. A 1Meg-ohm pot will attenuate even less than a 500K pot, so if you want to hear your guitar "wide open" you may want to try one.

    Notes on pot shafts and knobs:
    Some of our control pots have fine (24-spline) knurled shafts; others have coarse (18-spline) knurling. All our press-on knobs fit coarse knurled pot shafts, and will not fit fine shafts. To install a knob that has a set screw, such as our "dome" knobs, align the screw with the split in the pot shaft before tightening.
     
  3. Thats more info than I could ever give you. But I will say, to put it very simply, 500K pots produce higher output, so they will be mildly louder and almost shrill. Many pickup companys that make Single Coil (Jazz Bass) pickups will recomend 250K pots. 500K work better for humbuckers and soapbars.
     
  4. This one was never really answered: Split shaft (knurled) pots are for knobs that push on and solid shaft is for knobs that have a set screw to tighten them (these knobs are usually metal).
     
  5. afrodisiak

    afrodisiak

    Mar 14, 2006
    Singapore
    Geez! Thank god for you guys!
    I knew I'm in the right forum to pick up stuff about my new instrument! :hyper:

    Cheers!
     

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