Volume Controls and Loss of Highs

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by thetone, Mar 21, 2008.

  1. thetone

    thetone Member

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    I just put a new WCR wiring harness in my PRS CU24 including the controls and capacitor. It already had Fralin Blues Specials in it. The geetar sounds great but I do lose high end when I turn the volume control down. I need to be able to use the volume control effectively and this is a problem.

    Should I put a cap in between the two lugs on the volume control? Will that fix it or will that just reduce the highs when the control is wide open so that I don't notice the difference? I always remeber reading that Walsh cut the cap on his Tele and I thought that was the reason.

    I notice that Grissom says (on Lance's site) that his signature guitar does not lose any highs when the volume is turned down. How do they do that?

    Any suggestions? Thanks!
     
  2. walterw

    walterw Gold Supporting Member

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    the cap will leave highs in when turning down, and doesn't affect the all-the-way-up tone. did you put in a 500k volume? this allows more high end at "10" than a 250k, so you might be noticing too much brightness with the single coils on 10, especially with fralins, which are plenty bright, even his way overwound ones, much less the blues specials.

    joe walsh probably cut his out for the same reason i don't like it, namely that it makes the high end brittle and artificial sounding when turned down. the trick is to use a small-enough cap, like say, a .0003uF, that it will add back what you need without adding too much. the .001uF that you often see is IMO way too big, causing a harsh sound when turning down.
    you can also put a resistor in series with the cap (100, 200k?), effectively "turning down" its sound a little.
     
  3. RvChevron

    RvChevron Member

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    You can try using a 180pf capacitor in parallel with a 150k resistor across the input and output lugs on the volume pot.

    This combo is what Anderson and Suhr use on their guitars, I've tried it and they work pretty good. It sounds very natural on my Tyler H/S/S.
     
  4. otaypanky

    otaypanky Gold Supporting Member

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    I had similar complaints with some of my guitars, although none had the WCR pick-ups. I had the problem with both humbuckers and single coils. Just before I went ahead and changed out the wiring and pots on a few of them, I discovered it was the cables I was using. I had huge tone loss at reduced volume settings when using Monster Rock or Monster Jazz cables. I tried a George L and there was a world of difference. After switching to George L's, the reduced volume tone was so much better that I didn't need to change anything else ~
     
  5. blazzrock

    blazzrock Supporting Member

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    i am in the process of changing my mccarty trem wiring to dgt wiring specs minus the extra volume knob. the dgt has a 180pf capacitor across the input and output lugs on the volume pot and a paper and oil cap for the tone. i haven't got the paper and oil cap yet, but so far i like what the 180pf cap does for the highs when lowering the volume.
     
  6. JUS1BEER

    JUS1BEER Member

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    I also have a PRS CU 24 that has WCR pups in it. My CU24 is a bright guitar and so I am approaching it a little different. I have had it converted to a 1-volume,1-tone, toogle switch and 2-Humbuckers for a couple of years now (no single coil split) with 3 different brands of pickups. What I am doing now is waitng on a tone Pot that is a stacked or has two pots in one tone control. I am having them made to a 300/500 audio (log) and put the 500K on the neck and the 300K on the bridge pup to tame some of the highs. I will let you know how it goes. I will try different caps...I have a .033 ordered and have a .022 oil and paper Jenson now in there. I am not using a volume cap at this time but I think the PRS originaly came with a 180pf on the volume, I am thinking about doing this if I have any issues with losing highs when I turn down.

    I have an issue right now with the guitar getting brighter when I turn down the volume ???? This is with out any volume cap and I have it wired like is on the PRS web page modern wiring (2007). Could this be because right now I have a linear pot on the tone control???. I am going to get annother volume pot when the new tone pot comes in and start over. Should the volume pot be linear and the tone pot be audio (log) or should they both be audio. I do a lot of volume swells and want the one that does that the best.
    I think I asked more questions than I helped you sorry about that.
     
  7. thetone

    thetone Member

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    Thanks for the replies!

    I think I'll try a 180pf on the volume pot and see how that goes.
     
  8. A440

    A440 Silver Supporting Member

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    let me know how it works out. I'm a fellow Mctrem owner here :)

    do you have the stock pickups in yours?
     
  9. thetone

    thetone Member

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    I have the Fralin Blues Specials pups. Only the pots, wiring and a .022 tone cap come fom WCR. I changed the pots and wiring when I changed the 5-way rotary to a 3-position toggle.

    Anyway, I tried a 181 pf cap that I had and I couldn't hear any difference - in other words the treble still dissappeared when I turned the volume down. The only other cap I had was a .022 uf orange drop so I put that in there on the volume pot. Boy - now I understand what people mean by harsh! You definitely do not want to use a bigger cap that necessary to do the job.

    Yesterday I ordered a volume pot treble bleed cap/resister combo from Mojo. I think its a 471pf cap with a 220k resister if I remember correctly. I figured the 471pf would be large enough to do the job but not too large. I will report back.

    There's another thread under amps about how the /13 really holds the treble when you turn the guitar volume down. I'm playing through a Carmen Ghia but I was surporised to read that the amp would have anything to do with it. Sure would like to pick up a /13 tho!
     
  10. blazzrock

    blazzrock Supporting Member

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    i currently have stock pickups in my mctrem, but i've got some lollar imperial low winds on the way to try in it with the new wiring. jason lollar told me grissom wanted prs to use his low winds in the dgt, but paul will only use other manufacturers pickups in private stock guitars. so they had to make something similar to please grissom. they used grissoms favorite paf's from a vintage 335 he owns along with his favorite boutique pickups (lollar imperial low winds - also based on paf's from a vintage 335) as a benchmark for the dgt pickups. i figure if the low winds were what david initially wanted to use they have to be in the same ballpark tonally.
     

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