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An Ignoramus Asks...

Discussion in 'Pickups & Electronics [BG]' started by HCEarwicker, Sep 27, 2013.


  1. HCEarwicker

    HCEarwicker

    Aug 30, 2013
    London UK
    Me, I know a lot about music theory, got enough technique to get away with most things, but know absolutely nothing about how my basses work :( So -

    Here's the wiring schematic of my delightful Dearmond/Guild Starfire bass (2 x vol/2 x tone/3 position selector):

    http://www.dearmondguitars.com/pdfs/...ng_Diagram.pdf (*Late edit: WORKING link 1/2 way down this page)

    And here's my question:

    When I engage both bridge and neck pickups (middle selector position) and turn both volume knobs to 10 I can clearly hear the tonal characteristics of each pickup, combined. But if I turn down one or other vol knob below 8 I only hear the characteristics of whichever pickup I've left on 10. So engaging both pickups, with the neck vol on 10 and the bridge below 8, I only hear the neck pickup, and vice versa. This makes some sense to me, so I guess all is functioning as it should (is it?), but…

    Is it possible to re-wire my bass (= get someone who knows what they're doing to re-wire my bass) so that I get a gradual blend of pickups - from the bridge volume on '1' with neck volume on '10' (and vice versa) and all points in-between - as with active circuits?

    If that is possible, I have a supplementary question:

    I'm considering installing a tonestyler or two. Am I right in thinking that there'd be little point in having 2 tonestylers with my bass wired as it is (I do use all 3 pickup selector positions)? If I did re-wire for full pickup pan/blend would I get a whole bunch of subtle, graduated tones from 2 Tonestylers in combination with all sorts of different pickup blends? Or would one 'overall' Tonestyler give me just as much variation?

    Hope that makes sense!
     
  2. JustForSport

    JustForSport

    Nov 17, 2011
    Could be that the pots are of the wrong resistance value, or 'linear' as opposed to 'audio' taper causing the perceived volume to drop too quickly.
    Photos or list of type of pots installed would help, and others here know the values you need to get the correct taper.
     
  3. Crater

    Crater

    Oct 12, 2011
    Dallas, TX area
    What you're describing is pretty much normal for passive pickup systems. I don't think swapping the stock (I'm assuming your bass is stock) linear volume pots for audio taper pots will make that much difference.
     
  4. Wouldn't that be the contrary, as in having the volume quickly raise when turned up from zero, and then get only slightly louder as you turn the pot?
    +1 on the rest
     
  5. HCEarwicker

    HCEarwicker

    Aug 30, 2013
    London UK
    Thanks for the response, guys.

    Just in case I wasn't clear - the volume control for each pickup when solo'd works fine; increases gradually/regularly as it turns. Nothing wrong there. My query only concerns what happens when both pickups are selected:

    * Turn both neck and bridge vols to 10: I hear neck tone plus bridge tone. Smashing.
    * Keep neck vol on 10 and turn bridge vol below 8: I hear only neck tone
    * Keep bridge vol on 10 and turn neck below 8: I hear only bridge tone

    So I do have a band of 2-pickup blended tones to play with, but it's very narrow.

    So the first part of my question is: Is this normal in a 2 x vol/ 2 x tone passive system, as Crater suggests, or not?

    PS - The bass is stock, and wired as per the schematic.
     
  6. HCEarwicker

    HCEarwicker

    Aug 30, 2013
    London UK
    ...And the second part of the question: Can my bass be re-wired/modified to give me a wider range of pickup pan/blend of the kind you get with an active circuit - without 'going active'.
     
  7. abarson

    abarson

    Nov 6, 2003
    Santa Cruz
    Your current wiring is very common. It is the same found on Gibson Les Paul guitars, etc.

    I think a "Blend" or "Balance" potentiometer could be installed instead of the 3-way selector switch, but I've not done so myself. Since the blend pot has some resistance value, it could affect the tone as well.

    Myself, I would go with a single overall volume, blend, and one tone per pickup, without the switch. Sorry, but I don't have a schematic for this.
     
  8. It's audio taper pots that cause the steep dropoff. Check the graphs.
     
  9. HCEarwicker

    HCEarwicker

    Aug 30, 2013
    London UK
    Thanks, abarson. So I shouldn't expect the middle switch position of my standard Gibson-style wiring to give me a gradual blending of pickups using the 2 vol controls - just the sound of both pickups full 'on' (which I can then modify with either tone control). Is that right?

    And if I do re-wire for greater blend possibilities with a blend pot I may affect the overall tone of the bass, and not in a good way?

    (Other guys - Is the linear/audio/taper debate relevant to my question? Sorry, I'm not getting the connection.)
     
  10. Your link does not work, but I am curious which way the volume pots are wired. It is traditional to use the wiper terminals as outputs when there is a pickup selector switch, because the varied loads of the pots apply to the output, instead of the pickup coils, allowing a more consistent tonality throughout the range of control, and a better taper. It does not allow pickup blending, however, because each pot controls output impedance, so rolling either down too far will affect both pickups.

    You can try using the wiper terminals as inputs, and see where that gets you. It is important to note, however, that there is no "good" solution for blending two signals passively. When you adjust volume pots, you change both the loads on the pickup coils, and the impedance of each pickup. This is why people always have weird issues with both dual volume and volume/blend setups.
     
  11. HCEarwicker

    HCEarwicker

    Aug 30, 2013
    London UK
  12. HCEarwicker

    HCEarwicker

    Aug 30, 2013
    London UK
    OK. So I've searched, googled, youtubed and experimented a bit more...

    I think my confusion stems from the fact that I've always, for decades, played passive basses with vol and tone fully open, or pretty much so. I've now discovered that all sorts of possibilities open up with the 2 vol controls at settings less than 10 - like at 3 and 7! or 4 and 8!! - or even 3 and 8!!! -- not so much 2 and 9 tho'; the 9 overwhelms the 2 :( The tonal variations can be slight, but they're there. Apparently, many people have known this for a while, but it's news to me! Pretty dumb huh? :)
     
  13. HCEarwicker

    HCEarwicker

    Aug 30, 2013
    London UK
    [although I do get hum when neither pup is above 8. but that's standard...right?]

    Anyone care to comment on my discoveries?

    Maybe:
    'Congratulations!'
    or -
    'Still don't get it do you? Buy a pair of bongos.'

    ?
     
  14. tylerwylie

    tylerwylie

    Jan 5, 2008
    Dunwoody, GA
    Tis why I use active basses and also single pickup basses, lol.
     
  15. Don't they use audio taper pots for the exact reason that the log scale should be more akin to how human hearing perceives loudness?
     
  16. For mixing consoles, where you need to do fade outs. On a bass, it's a different application. The pot will go through half of its resistance range in about a fifth of the rotation, and that jump is very noticeable. The idea is to stretch the resistance out over the range so that you can blend signals without getting an all-or-nothing mix.
     
  17. I see, thanks.
     
  18. JustForSport

    JustForSport

    Nov 17, 2011
    So, blend pots are really linear (not 'audio' taper) pots, stacked, and wired oppositely?
    Then, better to have linear vol/vol pots and audio tone pots?
     
  19. It's better to use M/N taper than A/C.
     
  20. JustForSport

    JustForSport

    Nov 17, 2011
    Haven't seen pots listed that way- must be looking in the wrong places...
    I'll do more diggin-
    But maybe a blend pot is 100% thru half rotation to center, then tapers to 0%,
    each side, opposite direction for each half?
     

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