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Replacement(?) Preamp for '07 Warwick Thumb 5 NT?

Discussion in 'Pickups & Electronics [BG]' started by mencken, Sep 17, 2016.

  1. mencken


    May 18, 2008
    Chapel Hill, NC
    Looking for some advice...

    The scenario:
    I have an '07 Thumb 5 NT with stock electronics including a preamp that at least one guitar tech assures me is toast. (It's making weird hissing/swooshing sounds reminiscent of the "ocean" sound you get when you stick your ear up to a seashell.). I thought the problem was with the volume pot (on the stacked volume-pot/blend-pot/bypass-push-pull control) based on the fact that the noise was consistently baddest in the middle of the volume pot's range, and would only go away completely when the bypass switch was pulled and the volume pot was turned completely down, but the tech assures me that "bad pots don't sound like that" and it's the sound of "a bad preamp." (I have a replacement pot from warwick, but no burning desire to mess with the 15-or-so solder points that hold it to the board.)

    Question 1: Any suggestions (or practical experience) for confirming (or refuting, or refining) the "bad preamp" diagnosis before I buy a new preamp? I've got a new set of leads for my multimeter arriving tomorrrow (don't ask) , and I'm *hoping* that I can think my way through the signal chain and observed behavior well enough to do at least *some* degree of fault isolation. (Best case scenario, I'm able to isolate the problem to some ten-cent diode and rip it out and solder a new one in place.)

    Question 2: Other than replacing with a stock Warwick replacement unit ($240 if I order from Warwick; or $240 *and* a six-month wait if I order from the US distributor!), does anyone know of an aftermarket onboard preamp that would work with the Thumb's stock pot/knob/controls?

    Question 3: Does anyone know if Warwick will let you buy one of their new-fangled custom-shop preamps? (With the rechargable lithium battery and micro-USB charging port?)

    Question 4: I'm slightly in-lust with the Aguilar OBP-3 (SK/PP), which comes with its own tone controls, and (I think) would just leave me needing to swap out my stock volume/pan/push/pull with a stacked volume/volume control... but since I'm already departing from stock functionality anyway, does anyone know if it's possible to run an OBP-3 with three knobs as: (1) stacked volume/blend pots, push-pull bypass; (2) stacked mid-cut/boost and mid-sweep pots; and (3) stacked treble/bass pots? (I didn't see anything indicating that's a supported set of parameters, but I got the impression that some supported options or combinations thereof aren't all that well documented.

    Any assistance *greatly* appreciated!
  2. mencken


    May 18, 2008
    Chapel Hill, NC
    I practiced a little self-help on question #1... I wired the battery directly to the power wire on the pickups and ground on the jack and disconnected the preamp altogether, and... it sounds beautiful with the bypass pull control pulled (and, as expected, completely dead in the "push" position, trying to route to a preamp that isn't even there anymore.)

    So... fair-play to the guitar tech who knew it was the pre just by listening to it. And fair play to *me* for getting my bass usable again. (I rarely use the onboard EQ for much of anything, and don't mind playing it in "bypass" mode indefinitely while I make my mind up about a replacement preamp.)

    I gather from reading elsewhere that Warwick *isn't* selling the newfangled custom-shop preamp ala carte, and I had a good experience with a Mike Pope Flexcore I put in a Toby Deluxe a few years ago, but I think the Flexcore is a bit pricey in terms of dollars and real-estate, and I'm still feeling pretty bullish about the Aguilar OBP-3.

    So... anyone want to shower me with advice on a replacement preamp for a Thumb 5 NT?
  3. Brother Goose

    Brother Goose The Process IS the Reward!

    Dec 4, 2013
    Syracuse NY
    God Is Love
    Have BBG wire an OBP-3 for you! I'm sure you'll be very happy. I'm not a fan of MEC preamps
    mencken likes this.
  4. mencken


    May 18, 2008
    Chapel Hill, NC
    Exactly what I did, and it couldn't have worked out better! Love the tone of my Thumb with the OBP-3 and definitely notice some additional headroom.
  5. blixild


    Mar 4, 2006
    Buffalo, NY
    You have active pickups, right? If you swap the volume out, keep in mind that you'll need 50-100k pots vs 250-500k for passive pickups.
  6. mencken


    May 18, 2008
    Chapel Hill, NC
    Por supuesto!

    One of the nice things about ordering the OBP-3 pre-wired through BBG was that I could actually specify whether I had active pickups during ordering and they swapped out the pots without me asking.

    The only "wrinkle" I ran into was that I ran "knobless" for a week or so b/c I didn't think to compare the shaft diameter on the stock Warwick pots to the pots BBG shipped with my OBP-3. (Spoiler: they didn't match.)

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