1960 Fender Precision: Original Pot/Cap Values

Discussion in 'Basses [BG]' started by Turbocharbo, Dec 20, 2019.

  1. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    Hey folks

    I recently acquired a 1960 Pre-CBS Fender Precision refin. It plays like a dream but I find it gets a bit honky when I dial the tone pot down. I don't think the pots are original: the volume is a 1966 250k audio pot whereas the tone is a 1960 1M audio pot. I don't know what the cap value is but it's a yellow 'teardrop' style cap.

    Does anyone know what the original pot/cap values were for a 1960 Precision? What are good modern alternatives to original vintage parts? I'd like to restore it to it's original resistance values without breaking the bank and buying vintage parts.

    Thanks!
     
  2. ad9000

    ad9000 Supporting Member

    Mar 30, 2004
    Leucadia, CA
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  3. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    Thanks for that, I had a suspicion that that were the values.
     
  4. bobyoung53

    bobyoung53 Supporting Member

    Some of those early Fenders used 0.1 uf tone caps too. I put one in my Jazz as it was always trebly even with the tone knob closed and I still get plenty of snap with it open with the 0.1 uf cap but now it sounds like a bass with the tone closed. It originally has IIRC a 0.02 uf or something like that. I also tried a 0.047 uf cap but it still didn't bleed off all the treble, so in went the 0.1. These bigger caps don't really cut off the highs when open only make the range of the tone control wider.



    How Do Tone Capacitors Work? - Lindy Fralin Pickups
     
    Last edited: Dec 21, 2019
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  5. Having a 1M tone pot just gives you more range to work with. If you dial it down to 250k, it will sound exactly the same as a 250k pot turned all the way up.

    Honkiness when the tone knob is dialed down will be caused by the cap being a lower value than you prefer. You don't say what value the cap is, but I would guess it's .022µF or lower. As noted above, early Fender caps were often .1µF, but they switched to .047µF at some point. Personally I find .1µF too much; you just get mud when you turn down the tone control.

    The Fralin article referenced above misrepresents how a tone control works. But one thing Lindy says that is accurate is that in an electric guitar, the type of cap really doesn't matter, only the value. All the stuff you hear about the virtues of Orange Drops, Bumble Bees, or vintage PIO caps is complete nonsense.

    The electronics in a guitar form a resonating AC circuit known as an RLC circuit (Resistance, Inductance, Capacitance -- yes, the L stands for inductance). The pots and cap contribute to the R and C values; the pickup is the source of L, but also contributes to R and C. The cable connected to the guitar also adds to R and C. The input impedance of whatever the other end of the cable is plugged into also contributes to R, so your guitar sounds different going into the 1M impedance (usually) of an amplifier compared to the much lower impedance of most pedals. There is no tone "going to ground" in this system; rather, the signal produced by the pickup depends on the R, L, and C values.
     
  6. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    Thanks for the great explanation @Craig4003 . If I understand correctly the half way mark of a 1M pot will be the same as a 250K pot? I guess yes if the pot is linear but no if it's audio?

    The value of the cap in my 69P seems right, I'll make sure to match it with my 60P.
     
  7. Usually people prefer audio pots for tone knobs, in which case you get about half the value (500k if it's a 1M pot) at about 7, and 1/4 the value (250k for a 1M pot) at around 5.
     
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  8. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    I have to say that I prefer how detailed I can get with a 1M pot. Glad to know that a cap value change might get rid of that honkiness.