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Pots: Linear taper/Volume; Audio taper/Tone?

Discussion in 'Pickups & Electronics [BG]' started by JazzCrazy, Dec 9, 2018.


  1. JazzCrazy

    JazzCrazy Banned SUSPENDED

    Mar 25, 2018
    Joshua Tree
    Because of a nagging hum on my defretted Squier DJAV (sans active preamp) I will be replacing ALL my passive electronics--including pickups. Because of the original cheap active electronics it has factory shielding paint in the cavities. I already sent away for a Bourns 250k MN taper, center detente blend pot & a Switcraft barrel output jack. What's left to order are the 250k volume & 250k tone pots.

    Before sending away, I want to confirm that the Volume control requires Linear taper, & the Treble attenuation requires Audio taper pots right?.

    Interestingly, I came across a "no load" 250k Fender Strat pot that was supposed to be used either for volume or tone. I don't quite understand that.
     
  2. Hums and buzzes are caused by single coil pickups (50/60hz hum) and/or poor shielding (rf interference, power switching noise etc). I'm afraid replacing your pots won't make any difference. I'd recommend using humbuckers, and having the bass shielded properly. IME factory shielding paint on all but high end basses is next to useless. Also, the leads from the pickups into the electronics cavity should be good quality shielded wire. In fact any length of wire more than an inch or two that's carrying high z signal should ideally be shielded.

    But to answer your questions, yes a passive tone pot should be audio taper. A vol pot can be either, it's a personal choice. And no, a no-load tone pot won't work as a volume pot.
     
    Killed_by_Death likes this.
  3. JazzCrazy

    JazzCrazy Banned SUSPENDED

    Mar 25, 2018
    Joshua Tree
    Single coils do not make appreciable noise per se, otherwise they wouldn't ever be played. And two single coil pickups at the samw volume ARE humbuckers. Jaco, Marcus Miller, Geddy Lee, Brian Bromberg. Chris Squire, John Entwistle, Darryl Jones & others have made poor choices in your view. The fact is that not only are single coil basses played in live venues where the music totally drowns out the hum, but they have been regularly recorded for decades using just one rear pickup as Jaco did

    I played a Rickenbacker 4001 in high school & then gave it up to focus on trumpet. No audible noise! 40 years later I heard a recording of Marcus Miller playing "Redemtion' from his album Renaissance, & his growly sound reminded me of my Rickenbacker--only it had balls! It was that sound that brought me back, not my recollection of Steve Swallow's nasty 20 ohm " Mudraker's" in his EB-2 (though I liked hearing him with Gary Burton in the 70s).

    BTW, Bartolini side by side split coils ain't single coils. I've tried them & they suck!

    The truth is that when I had Carvin j99a's installed in this same bass (@ Nordstrand) no hum! After having a falling out at Nordstrand (because they make their own bass repairs entirely a prriority) I went elsewhere, & made the mistake of switching to Carvin JVAs which DO come with shielded cables; & then adding an Aguilar OBP-2 (BIGGER MISTAKE) & now has been unplayable since August 2016, even with that brittle OBP-2 removed. This isn't your standard single coil hum. It's not faint, it's intolerable & can be heard in any live situation.

    BTW, you commented on my luthier's inquiry about my Marcus Miller bass, & he finally finally found a frayed wire. Now it can be played even though it has single coils.
     
    Last edited: Dec 9, 2018
  4. JazzCrazy

    JazzCrazy Banned SUSPENDED

    Mar 25, 2018
    Joshua Tree
    I posted this thread for a reason. Last time my luthier (using spare pots lying around) failed to put in an MN taper blend pot (there's a decrease in volume in the center position, even when reversing the wire phase, & I question if the other tone & volume are the right type. I want to leave nothing to chance & drive there with the right pots & make one last 130 mile round trip to make this bass playable. I don't need someone to tell me my taste in the Jazz bass is somehow wrong.
     
    Last edited: Dec 9, 2018
  5. good luck
    :cool:
     
  6. I can promise you that all those guys have experienced single coil hum. When they record, sometimes you have to face a certain way or whatever.

    I misunderstood your post and thought you were hoping to cure your nagging hum by replacing your pots. I apologise and wish you all the best with your mods.
     
  7. JazzCrazy

    JazzCrazy Banned SUSPENDED

    Mar 25, 2018
    Joshua Tree
    Thank you. Part of the hum issue on the Marcus Miller bass was a bad blend pot (In addition to that frayed wire).

    In this fretless bass being worked on the 250k pots that were installed apparently were from a box of spare parts lying around, & are either cheap or used. Now when I turn the volume & blend controls the output level cuts in & out & does crakle & hum. So these Bourne pots I ordered should last.

    Prior to this, the pots were 500k all around & sounded too bright & brittle. Then the bridge Carvin JVA pickup was dead quiet by itself but the neck pickup hummed loudly both by itself, & with the blend position in the middle. So this defies logic & isn't your typical single coil 60hz hum. I do suspect the stock Squier barrel jack might also have a hand in this.

    I'll take your admonition about the factory installed shielding paint to heart & deal with that aggressively. Thanks
     

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