Odd interaction between volume pots - advice neded

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by slidincharlie, Jan 8, 2008.


  1. slidincharlie

    slidincharlie Member

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    I have just replaced all the pots and the neck pickup in my '66 Guild Starfire V (2-hb, 2-vol, 2-tone, master volume).
    Everything works fine, but I note an odd thing:
    when both pickups are engaged, rolling off one volume pot a little bit excludes almost completely that pickup. In other words when the neck pickup is on 10 and the bridge pickup is on 9, I hear almost exclusively the neck pickup (and viceversa). If I tap on the 'weak' pickup poles I can still hear it, but its contribution to the blend is almost null.
    Thus I can't blend the two pickup appropriately. :(
    Have you guys ever noticed this with your two-hb guitars?
    I have an Epiphone 335-style guitar whose pickups I can blend freely.
    My Starfire is wired as in the schematic below: the pickup hot lead goes to the volume's center lug, in order to have 'independet' volume controls. No treble-bleed cap for now.
    --Carlo[​IMG]
     
  2. John Phillips

    John Phillips Member

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    Connect the pickup hots to the CW terminals of the volume pots and the switch to the center terminals. If you want the '50s-style wiring' (better preservation of treble as you turn down the volumes), leave the tone caps connected to the center terminals.

    The only advantage of the 'independent' wiring is that neither volume control mutes the whole signal when turned right off - apart from that there's nothing good about it at all.
     
  3. slidincharlie

    slidincharlie Member

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    Thank you John.
    My viewpoint is different though.
    I knew your wiring trick, but in this way if I roll off one volume when both pups are engaged I'll get a lower overall output, and I don't want this effect (since I use the central position quite a lot).
    I'd like to blend the two pickups when they are both engaged, then adjust the guitar output with the master volume. Blending the pickups to taste and adjust the overall volume with the master is a great idea IMHO, but for now I am not able to obtain that blend :(
    Or am I missing something? :confused:
     
  4. John Phillips

    John Phillips Member

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    You won't get an overall lower output unless one of the two pots is close to zero. Over the normal range where blending works (10 down to about 7) the volume of the pickup that's full up isn't affected significantly.
     
  5. slidincharlie

    slidincharlie Member

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    I see... I must try then.
    I'll also follow the cap trick, and see if this is enough to avoid a treble-bleeder.
    In fact I was wondering if I had to install one treble-bleeder on the master volume or rather one on each single volume...
     
  6. David Collins

    David Collins Member

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    I seem to be in a minority by preferring linear pots in a Gibson-style volume setup, but with your setup (neither volume acting as master in middle position) I think they are significantly better than audio. You have a volume setup more like a Jazz Bass in the middle position, and I think a linear pots give a much broader usable range than audio here. You could still keep the audio master volume if you like the rapid drawback from 10-7, and smoother kill from 3-0, but I'd recommend linear for the individual volumes.

    I'd probably also go with a 1meg master volume, as you already are down to 250k in neck and bridge positions, and about 166k in the middle position. Probably loosing a fair amount of highs you may want to keep there.
     
  7. slidincharlie

    slidincharlie Member

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    John,
    I switched the wires on the non-grounded lugs of each volume pots and it worked exactly how you describe. I was preoccupied about the output loss within the effective blending range, but now I can blend the pups to a sufficient degree without output loss as long as I keep one volume pot at 10.
    Now I'll have to get accustomed to this setup, which is entirely new for me...
    Thanks,
    Carlo
     

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