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Log/lin pot A/B suffixes & prefixes

Discussion in 'Electronic Repair' started by N Cook, May 10, 2007.

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  1. N Cook

    N Cook Guest

    Does anyone know of any standard or authorative source for such
    designations.
    eg
    50KA - lin ?
    50KB- log ?
    50KAB - lin/log , semilog?
    50KBA - log/lin ?
    and does a B prefix mean a centre pick off fourth terminal, or 1/3&2/3, or
    any fixed track tap terminal or what if anything a B prefix means. ?
    And while at it any other letter designations eg for cosine track, or even
    wire/wound etc
     
  2. Ron(UK)

    Ron(UK) Guest


    I think it`s A = lin, B = log except when it isn`t ;)

    the marking conventions changed some time ago



    http://sound.westhost.com/pots.htm#markings

    Ron(UK)
     
  3. Ron(UK)

    Ron(UK) Guest

    No no, it`s part of a wonderful resources site ESP which contains a
    huge amount of useful info http://sound.westhost.com/

    I thought that I`d put a attribution to the site just before my header,
    but it seems to have gone awol.


    Ron(UK)
     
  4. Eeyore

    Eeyore Guest

    A = linear (European) or Audio taper (Japanese).

    B = 'log' taper (European) or linear (Japanese)

    Graham
     
  5. Eeyore

    Eeyore Guest

    There are no meaningful conventions except that C universally means 'reverse log'.

    Graham
     
  6. N Cook

    N Cook Guest

    so its a matter of ignoring everything other than the likes of 50K and
    measuring ohms at 1/4,1/2,3/4 and full track
     
  7. Ron(UK)

    Ron(UK) Guest

    connecting the pot to an analogue meter and sweeping from end to end
    will show whether it`s log or lin.

    Ron(UK)
     
  8. Eeyore

    Eeyore Guest

    What does the resistance value have to do with it ?

    1/2 rotation only. Most of the tapers you're likely to find in audio are
    typically specified @ 50% rotation as a percentage of 100% resistance. Audio and
    reverse log are usually 15% for example (depending which end you're measuring
    from) although I have used semi-specials such as 5% reverse log for mic amp gain
    pots.

    Graham
     
  9. You don't even need to go that far. Set to approx 1/2 travel and measure
    one side. Linear will be near 50% - log very much not.
     
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