Blend pot with passive P and J

Discussion in 'Pickups & Electronics [BG]' started by FourBanger, Jul 15, 2013.

  1. FourBanger


    Sep 2, 2012
    SE Como
    I only have experience with blend pots on basses with soapbars, passive and active.

    Does anyone have any feedback regarding the use of a blend pot in a bass using passive P and J pickups, witlh or without an active preamp? It seems nearly all passive PJs use two individual volumes but those with an onboard preamp use a master volume and a blend.
  2. P and J pickups usually don't mix well due to their different output impedances. When you have a blend pot, it highlights the fact that blending is uneven and causes volume drops.

    VVT is traditional, and thus, common. The reason for blend pots on basses with preamps is generally the acceptance of a non-traditional feature. Though the preamp itself has no relation to blend pot behavior, other than providing an input impedance that is constant, through all rigs. There are active blend pots, however, which eliminate some of the issues inherent to passive blending. They tend to be uncommon.
  3. Bongolation


    Nov 9, 2001
    No Bogus Endorsements
    Yes, switch them and be done with it.

    Pickups don't mix; they interfere with each other.
  4. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    that's a good way of putting it; you're not "mixing" two different pickup sounds together, the two pickups are electronically combining to create a distinct, third sound.
  5. Bongolation


    Nov 9, 2001
    No Bogus Endorsements
    Yeah, sometimes that works.

    The problem is that people seem to think of pickups in hydraulic terms, as though the pickups were a couple of gravity-fed water tanks emptying through a couple of spigots into a common trough.

    But it isn't hydraulics, it's electronics and (worse) AC electronics at that. Those pickups thrown together in the same screwy passive circuit mainly fight with each other rather than blend or mix, constantly changing with every electronic real-time variable, and there are a bunch. :(

    I personally don't want to mess with it. Switch them and let them be.
  6. By saying "switch them", you're saying select one or the other-do not blend either with a blend pot or individual pots?

    Is a pickup selector (ie.: Les Paul guitar) preferable to VVT setup?
  7. Yes.
  8. Matthijs

    Matthijs Supporting Member

    Jul 3, 2006
    A 3 way switch is preferable if you don't want to control the interaction between the two pickups and are satisfied with the sound of them both fully on. A lot of pj users want the whole spectrum of sounds you can get from a pj. Dialing in those sounds on stage can be finnicky though. My personal solution is a 6 way switch with my most 'prefered blends'.

    A blend pot on a passive pj with the right values will do just fine too. Just don't expect it to react completely linear. All that weird interaction between the p and j is an advantage, not a problem.
  9. Bongolation


    Nov 9, 2001
    No Bogus Endorsements
    Yes. Like the Tony Franklin. One or both, with 1V/1T.

    Yes. In some extreme cases (like the HRPB) the volume pots won't even work to mix anyway, so you might as well switch the pickups and be done with it.

    I've never understood the fiddly obsession with trying to mix pickups in the first place, especially on a bass, except when by blind accident there's a funny conflict that sounds kind of neat. That's OK, but for good, pure native tone from the pickups, you need to get them unhitched from each other.

    I keep waiting for some clever lad to find a good source of inexpensive quality 3-position rotary switches to drop into the first V hole on passive P/Js with V/V/T to do a tidy retrofit for this.
  10. SGD Lutherie

    SGD Lutherie Inactive Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    If they are made to work together, that's exactly what you get; a third tone. That's what I strive for with a matched set of pickups. But the neck can't be too hot.

    When someone decided to tack a J pickup on a P bass, you discover that they don't blend well.

    I did this recently for someone. The P is a standard wind (David Allen pickupÂ… sounds great), and so he wanted a very hot/dark bridge pickup. Came out great.

  11. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    I like changing out the J bridge with an end-to-end pickup, like DiMarzio UltraJazz, a Fralin Split-Coil J, or such, as they keep a good J-style bridge tone (not necessarily "vintage," but if you're going P/J, it's not vintage going in) and better blend. But still wired V-V-T.
  12. walterw

    walterw Supportive Fender Commercial User

    Feb 20, 2009
    sure, if nothing else the J won't hum.

    that makes sense though, a split-coil J is electronically more like a P pickup, so the behavior through the volume and/or blend pots might be more consistent between the two.

    still, there's no reason a regular single coil J can't work with a regular P, blend pot or not; if it makes a sound you like, then by definition it "works". (don't dig it myself, but who cares?)
  13. Grissle


    May 17, 2009
    Not my favorite normally but the SD quarter pounder jazz works really, really well with a P pickup.
  14. grovest


    Feb 26, 2002
    I owned the Tony Franklin and enjoyed its sound immensely. The stock pickups do create an interesting blended sound. An imperfect sound is a legitimate and interesting musical option, otherwise we'd be playing function generators hooked up to metronomes. I understand now much more so how the pups interact with each other. Because I couldn't leave well enough alone, I swapped the Franklin stock pups for Fralin P / Nordstrad J, which was extremely cool although the J was a little soft in comparison the P. A thread I made about the configuration brought out some of the same points made above. If anything, the experience made me warm up to the concept of active onboard electronics.
  15. sotua


    Sep 20, 2004
    Somewhere in time
    I did this in a JBass with a 4 position switch. Neck, Neck+Bridge series, Neck+Bridge parallel, Bridge. I did this because I really don't use blend... I play either both pickups or just the neck one when I wanted to sound somewhere in the vicinity of a PBass. The series option puts me in the vicinity as well, and I get definite switching instead of blending full on each side.

    The fit, however, was tiiiiiiight. After wiring, I could barely put the control plate back in.
  16. Matthijs

    Matthijs Supporting Member

    Jul 3, 2006
    Hey Bongolation, why not use a blend pot instead of a rotary switch? Just think of it as a rotary 3 way and ignore al the interesting stuff inbetween ;)

    You can wire a blend pot without shorting to ground, so it will have no effect on your pure p sound.
  17. SoVeryTired

    SoVeryTired Endorsing nothing, recommending much

    Jul 2, 2011
    Milton Keynes, UK
    I've owned four basses in my relatively short 'career' and three were passive PJs (I still have two of them). One had a blend pot - a nice thought but I didn't really notice a difference unless it was at either extreme or dead centre, where something different to either individual pickup was produced. It's the same tone I've experienced on all my PJs - a scooped, refined, slightly quieter but articulate sound that (for me so far) works well for slap and for quieter fingerstyle playing.

    The second one (which I still have) has two individual volumes. Again, forget trying to blend them to any precise ratio - it's P full, J full or both full, with no subtleties in between. The volume pots seem to function more like on/off switches if one of the other two is on. Three very useable tones, but really only three.

    The last one, my main player (5 string) has the perfect configuration - a four-way rotary switch. Each pickup solo, both together in parallel (the typical mixed sound that I got from the other basses) and both together in series. The series setting is my favourite of all the four - more growl, more mids, hotter output.

    I'm no electronics whizz but if I bought another P/J I'd be wanting a four-way switch or some other way of getting that series option (via a toggle or push/pull pot). That to me is the best setting of all. So while I think a three-way switch is a good option, and cuts out all the unusable stuff, four-way is the best way. :)

    (In fact, I've just talked myself into the first mod if I ever get roung to modding my cheap VVT bass.)
  18. SGD Lutherie

    SGD Lutherie Inactive Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Two P pickups sounds very cool! I had a P bass like that once.