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Linear vs audio taper whats the difference?

Discussion in 'Pickups & Electronics [BG]' started by DirtPoorRobins, Apr 13, 2008.


  1. DirtPoorRobins

    DirtPoorRobins

    Joined:
    Apr 18, 2005
    Location:
    The wild wild midwest
    I need to replace the direct out pot on my amp and its labeled as c10k from alpha, ive tried searching and could only find is the Alpha Pot 10k linear and audio taper pots, which one is the right one, or what is the difference?
     
  2. Jaco D

    Jaco D

    Joined:
    Nov 19, 2006
    Location:
    Toronto, Ontario, Canada
    In linear taper pots, the change in output as you move the pot linearly from center indent to the max in either direction is "linear" (Yeah, it's a crappy definition), as compared with an audio pot wherein as you move the pot linearly from center indent to max in either direction, the change in output is small the closer you are to center indent and larger as you reach the max position in either direction. I think the term here is it follows a logarithmic pattern (remember your maths?).
     
  3. bongomania

    bongomania Gold Supporting Member

    Joined:
    Oct 17, 2005
    Location:
    PDX, OR
    Disclosures:
    owner, OVNIFX and OVNILabs
    Audio = logarithmic, yes. The response is like an arc instead of a straight line, so that there is a wider usable range in the middle of the pot turn. Most audio controls are designed around an "optimal" range of effect on the signal, so it helps to have more control around that optimal range and less at the extremes.
     
  4. musicelectronix

    musicelectronix

    Joined:
    Jul 8, 2007
    Location:
    Hüstın, TX
    Disclosures:
    Lead Designer, Zeibek Boutique Pedals
    Actuallly, it is more related to the human perception of loudness. When the level increase in a linear manner, human ear hears it as a derivation of a third degree curve. In other words, the perceived loudness is not linear, it is more like an S curve (it slowly increases and then suddenly a giant increase in 1/4 of the rotation of the pot).

    this actually applies to the volume controls. In other type of controls, linear is always the safe bet unless known otherwise. For example, audio taper pots do not work very well in the feedback loop of the opamps and the perceived gain increase is less natural compared to audio taper pots.

    In your case, what you are holding is a *reverse* log pot ( "c" stands for reverse logarithmic / reverse audio taper). If they put a reverse log pot there, they certainly had a very good reason. I would suggest try to find a reverse log taper pot, which I am 99% positive mouser have. Check the 24mm alpha pots.
     
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  6. Jaco D

    Jaco D

    Joined:
    Nov 19, 2006
    Location:
    Toronto, Ontario, Canada
    That makes sense. I've heard/seen "a" pots and "b" pots so I wasn't sure what the OP meant by a "c" in his pot casing. If audio pots are not as abundant as linear pots, then I guess those reverse log pots are as rare as unicorns.
     
  7. i_got_a_mohawk

    i_got_a_mohawk

    Joined:
    Feb 9, 2005
    Location:
    Edinburgh & Dundee, Scotland
    They arent tooooo rare. But hard enough (it is reverse log pots for volume on left handed guitars an basses is it not?).

    I remember spending an age looking for them, it is possible to use a regular log pot and it just works backwards or something. Im sure there was a way around it, but i cant remember off the top of my head.

    Maybe best contacting a local tech or the company who make the amp for the parts
     
  8. niftydog

    niftydog

    Joined:
    Jun 23, 2005
    Location:
    Canberra, Australia
    Well, sort of... if you want full volume to be fully anti-clockwise, then sure you can do that, but most of us are trained to think the other way!

    One way to bodge pots is to install resistors in parallel. All the important stuff is right here.
     
  9. LeftHandedFrog

    LeftHandedFrog

    Joined:
    Dec 29, 2008
    Location:
    Copenhagen
    Hey guys!
    I m not sure i understand it all but i have a question:
    I got a lefty G&L L1500 a couple of weeks ago(great bass!!!) but something bothers me with the electronics. The active part is busted so i exclusively run it in passive mode: The bass cut is way too strong on the first like 15% and from there it makes no difference. It also takes a lot of volume.
    The treble cut is the opposite , i have to turn it almost all the way off to hear some change. It makes it tricky when you play live .... I showed it to a tech in Paris that told me it might be because those pots are right handed audio ones wired left hand way.
    Can that be true?
    On my Alembic Epic two out of 4 pots work right handed way , is that why?
    Should i try to find left handed ones or can i just rewire them right handed way and get used to that? Or is it all wrong and something else is f****d in my bass?
    Thanks
     
  10. LeftHandedFrog

    LeftHandedFrog

    Joined:
    Dec 29, 2008
    Location:
    Copenhagen
  11. line6man

    line6man

    Joined:
    Jun 20, 2008
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    Close to Los Angeles, CA
  12. niftydog

    niftydog

    Joined:
    Jun 23, 2005
    Location:
    Canberra, Australia
    Yes.

    Could be.

    Can't definitively answer this without physically investigating the bass, but it sounds like you could have one, the other, or a combination of the above scenarios.
     
  13. LeftHandedFrog

    LeftHandedFrog

    Joined:
    Dec 29, 2008
    Location:
    Copenhagen
    Thanks ..... i ll try to wire them on the other way and see what it does....
    I m wondering how that could happen though with such a good guitar maker like G&L
     

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