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Ideas for wiring active pickups

Discussion in 'Pickups & Electronics [BG]' started by sirsam22, Sep 28, 2017.


  1. I just bought a Peavey RSB from Reverb. I got a decent deal on it because it has everything but the guts. It uses two active pickups and three holes for pots. The factory setup for these is Volume Blend Tone, but since I'll have free reign on control options I though it would be fun to crowdsource some ideas and double check what I feel like I've learned so far from my research.

    First, since the pickups are the only active part of the circuit, am I correct in saying that you can wire it just like a passive bass with the addition of a battery before the jack?

    Second, the only difference in the choice of pots is the amount of resistance? So, I would use 25k or 50k instead of 250 or 500.

    Third, I could go V B T like the original setup. I could also very easily go V V T. How difficult would it be to do something like V/T V/T (with a cap or dummy switch over the last hole) or V/B T T so that each pickup has it's own tone knob? Would active pickups have the same issues with signal crossover as passives? If so, would you just add transistors like with the 60's jazz setup, and what values would you use? Would they need to be different like the pots?

    Fourth, are there any other control layouts that would easily work with 3 holes?

    I have thought about preamps, but I like the idea of 3 bands. It doesn't seem like there are a lot of options for 3 knob, 3 band preamps for active pickups. I'm also not trying to spend $100+ to put guts back in it right now. It's a strong possibility for later. Thoughts on models that would work?
     
  2. 1. The wiring is the same as with any other set of pickups. VBT, VVT, etc. are all possible. However, it should be noted that your pickups likely have a single conductor output, so you can't do phase inversion or series/parallel switching. (Not that you were planning to, anyway.)

    2. Active pickups have a lower output impedance than passive pickups, so you use lower resistance pots, such as 25k or 50k. Beyond that, all of the usual stuff about taper and loading is the same.

    3. Having two tone controls on a bass is problematic. You will need to isolate the tone controls with resistors if you want them to work independently when the volume pots are turned up, but that is going to kill output. Les Paul style wiring schemes that incorporate pickup selector switches are popular, because the switch allows you to sort of toggle between tone "presets," but otherwise, VVTT schemes mostly fell out of usage in the 1960s.

    4. VVT, VBT, or VT3 are your best choices. Those are tried and true control schemes with no gimmicks.

    Regarding preamps, it is best to avoid using one, since your pickups are active. The pickups already give you a buffered output, and chaining gain stages leads to decreased headroom and added noise.
     
    58kites likes this.
  3. I love this forum.

    Thanks for confirming all that. I had read about the not being able to do series/parallel switching.

    I'm not dead set on VT VT, but I really like the idea. I recently modded a bass to a mirrored double P with that wiring, and don't feel like I have any issues with tone crossover. I don't remember what value resistors I used. I do remember they were on the lower end of the spectrum. I did a lot of research before committing to it. There's a comtingent out there that argue modern capcitors (not PIO) really do a lot to help the isolation along with the resistors. Of course, I'm not running both pickups wide open most of the time. I like having a little more versatility, but it's definitely not necessary.

    By VT3 do you mean a three way selector switch?
     
  4. Nonsense. All capacitors sound and behave the same way, in this application. You won't hear any differences between modern compositions and PiO caps unless you are comparing capacitors of different values when manufacturing tolerance allows variation.

    Yes.
     
  5. bigtone23

    bigtone23

    Dec 10, 2014
    Denver, CO
    Zoobiedood likes this.