Vol/tone - series/parallel?

Discussion in 'Pickups & Electronics [BG]' started by Andy GG, Jul 24, 2018.


  1. Andy GG

    Andy GG

    Jun 17, 2018
    Scotland, UK
    Hi.

    I'm preparing long post and one detail got me thinking.
    As far as pots are concerned I like to connect signal into lug2 (wiper) and have it send to lug1 when left turned or to lug3 when right turned. That's for logic clarity sake.

    Now when you connect the tone pot you can either run the wire from vol's lug2 (clear untouched signal) or from vol's lug1 (lower quieter signal when volume gets down), as in drawing below:

    series or parallel.png
    The (A) variation shows it as a literal diagram, but the (B) as a simpler version of it got me thinking.

    It seems that running wire from vol's input lug2 to tone (drawing 1) makes the vol/tone connection a parallel relation, and running wire from vol's output lug1 to tone (drawing 2) makes it a series?

    Do I got it correctly and does it even matter? If it does matter in any way then how would each of the connection variations affect the tone?
     
  2. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    The cap is on the wrong lug in 1 & 2, it goes on the right lug.

    Here's the difference:

    Having the volume drop before the capacitor means that when you lower the volume you're also lowering the cut-off frequency, because

    RC-lowpass.gif

    This is a R/C filter (resistance/capacitance), and

    Guitar Pedals: R-C Filter Calculator

    this^ is a R/C calulator

    If you put in the values, you'll see that adding resistance lowers the cut-off frequency.

    As a result, having the volume drop before the cap causes more interaction between the volume & treble cut knobs.

    If you already have the treble cut rolled back some, it will be rolled back even more when you lower the volume more.
     
  3. Andy GG

    Andy GG

    Jun 17, 2018
    Scotland, UK
    I did suspect that theoretically lowering volume in connection no.2 may introduce additional resistance into cap indeed, but didn't expect it to be true in practice.

    So basically you say that connections 1 and 2 in drawing below are more reliable (or at least more predictable) than the no.3 , is that correct?

    series2.png
    Are vol and tone pots in series to each other?
     
  4. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive


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