PRS Custom 22 w/ Dragon I's. Love them rolled open but....

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by Fretmaster, Jan 31, 2006.

  1. Fretmaster

    Fretmaster Member

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    I HATE the way they get dark and muffled when I roll back on the guitar volume. I am the type of player that really moves around alot between pickups and constant volume knob changes. I need to be able to roll back on the volume and get nice and clean and open tones. Almost every one of my guitars have low output vintage style pickups in them which do this very well.

    My Custom 22 is one of the few exceptions as I feel the Dragon I's aer fairly hot and for what I use that guitar for I LOVE the tone with the guitar volume on ten. But, as stated I hate the way they react to rolling the guitar volume knob back. Is there anything I can do to make it get clean and stay open and clear sounding when I roll off without yanking the pickups and replacing them??:(

    Thanks, Steve
     
  2. mavrick10_2000

    mavrick10_2000 Member

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    Yes there is.

    You can add a high-pass capacitor to the volume pot.

    Here are some instructions from Guitarnuts.com under his mods section:

    The (sometimes) Problem:
    Sometimes the volume control on your guitar will almost seem to function as a tone control -- as you turn the volume down you lose some of the high frequencies. This is a function of the pickups, tone and volume controls, and the first gain stage reacting with each other to make up the complete circuit. The theory of why it happens is far beyond the simple discussions on these pages -- let's just say it sometimes happens, and that a guitar which is really plagued by this when plugged into one amp may suffer little when plugged into another amp or a stomp box.
    This is one of those modificatons that I can not recommend either for or against. Sometimes it seems needed, other times it is a waste. Which it will be for you depends strictly on your ears and on the particular guitar/amp combo you're dealing with. I've done it on one guitar (a cheap Korean Squier) and noticed a significant improvement through one amp while it made little difference with another (the second didn't have the problem as much to begin with).
    It is interesting to note that some guitars are manufactured with a bypass capacitor on the volume pot -- and some people take them off. Other guitars are manufactured without a bypass capacitor -- and some people put one on. It's purely a matter of personal preference, as you can see.
    The Solution:
    If you decide you need to do this, simply place a very small capacitor (0.001uf or thereabouts) across the "high" end of the volume pot and the pot wiper. I've also heard of people additionally placing a 150k fixed resistor in parallel with the capacitor -- I never used the resistor so I can't speak for how effective that is.
    [​IMG]High-bypass Capacitor on Volume ControlYou can also replace the volume control with one having a push/pull switch, so that you can switch the bypass capacitor out of the circuit when it is not needed -- thus having the best of both worlds. If you use the switch I would recommend the resistor – it should prevent the capacitor from building up a charge and causing a "pop" when the switch is opened or closed.
    [​IMG]High-bypass Capacitor on Volume Control with Switch
     
  3. msnl

    msnl Member

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    Hello,

    A PRS 22 has a 180pF capacitor as treble bleed. I've tried diffent values (.001uF and 680pF with a 150Kohm resistor) but changed the value back to the original one. I found my guitar to get to bright. It's also depending the amp you use. I use a Soldano for most of the time.

    For more info check this link:
    http://forums.birdsandmoons.com/forum/showhread.php?t=21224

    grtz,

    MSNL
     
  4. Fretmaster

    Fretmaster Member

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    Thanks for all the great tips. Mine is a 2002 Custom 22 with the rotary knob. I think you're right John, in that it may be more a problem with the fundamental design of the pickups. I've had a set of WCR Goodwood's I've been wanting to put in something. Maybe it's time I give them a whirl in the C22. I would also like to get rid of the rotary know and go with push/pull knobs and a toggle. Anyone in Maryland or surrounding area I could take this guitar to and have the work done. If I wait until I get time it could be a while. Of course is goes without saying hopefully someone that does really good work. ;)
     
  5. John Phillips

    John Phillips Member

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    If you're in Maryland maybe you should have the factory convert it to 3-way/push-pull... :)

    I'd try that first, then if it doesn't make enough of a difference, think about increasing the cap size. What cable are you using? This is important, since the treble loss is actually a function of the capacitance of the cable, even though it's affected by the tonal spectrum of the pickups too. I use a 20' Horizon, because I like the tone when the volume is up full, but it's quite high capacitance which is why I need a value as large as 680pF to match it. For a shorter Horizon type or a 20' 'bright' cable, somewhere around 330pF might be closer, and the stock 180 is probably about right for a very short, bright cable.

    If that doesn't work, it's the pickups...
     
  6. Fretmaster

    Fretmaster Member

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    Thanks for the suggestion. I think I will give PRS a call to check cost and turn around time. As for cables, I use Klotz cables exclusively through my entire set up. They are very low capacitance cables and tend to be very open and brighter than most any cable I've used. I'm glad to hear you (so to speak) bring that up. I've been called anal many times for tweaking my rig right down to a specific brand and type of cables. A lot of poeple don't realize how big a factor something like instrument and speaker cables can be.
     

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