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bartolini ezq preamp

Discussion in 'Pickups & Electronics [BG]' started by David Wilson, Jun 24, 2003.

  1. David Wilson

    David Wilson Administrator Staff Member Administrator

    Oct 14, 2002
    Lower Westchester, NY
    Anyone have any info on these? Schematics, specs?

    I have a chance to try one out, and I'm intrigued as it's parametric.

    I've done searches on the net and here, and all I can find is that it's discontinued.

    There's nothing on the Bartolini site, although I guess I could call/email them and ask. And who knows, in a years time, I might even get a response
  2. FBB Custom

    FBB Custom TalkBass Pro

    Jan 26, 2002
    Owner: FBB Bass Works
    If you get a wiring diagram, I'd be thrilled to get a copy. I have an old one sitting around, but it's been wired to ridiculous sliders and unmarked pots so I have no idea what the wires mean.

    TJ Wagner (the East Coast Bart rep) told me to fax Bartolini. I never have (I don't have a fax machine).
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  4. I had one of these that I bought maybe 15 years ago, stuck in a bass, then pulled out and stuck into a stomp box. I think that I still have it laying around somewhere--will see if I can either find the wiring diagram or figure out how it's wired up from the stompbox (providing I can still find that).

    At the time, I was trying to imitate the Wal sound with my Kawai. All I remember is that the EZQ was very good at adding midrange...

  5. No schematic, but I managed to dig tha actual stompbox out with the EZQ installed. It requires a pair of 50Kohm concentric pots. Anyone interested enough for me to make some pathetic attempt to trace the wiring and figure out where the heck everything goes?

  6. David Wilson

    David Wilson Administrator Staff Member Administrator

    Oct 14, 2002
    Lower Westchester, NY
    Sure, having a real world example to reverse engineer is much easier than looking at a box with a bunch of colored wires sticking out of it.

    If you get stuck you could take a photo and I could make my own pathetic attempt at helping. I'm sure we could narrow it down somewhat using the pot and jack wirings (inputs,outputs etc) and make educated guesses about the rest.

    There's one up on ebay right now, and if the price stays low enough my curiousity may get the better of me. And the funny thing is I'm generally not that big a fan of Bart stuff, but puzzles are fun :) And besides, this is almost certainly easier than trying to get the information out of Bartolini.

    Also, I'm going to have to look at a catalog but aren't 50K concentric pots kind of hard to get?
  7. Okie dokie--will try and trace things down tomorrow. I started it tonight, and it was mostly straightforward. However, being in a stompbox, there's also an on/off switch, and I can't remember which tab is which in terms of the switch function. Likewise, I don't quite remember which tab is which on the enclosed jacks.

    The pots were indeed hard to get and expensive. At the time I ordered it (waaaaay back), I think I paid $70 for the preamp, and $14 each for the pots. They had to be special ordered through Bartolini.

    Heck, if if comes down to it, I haven't used this thing in about 12 years--I could probably be persuaded to let you have it for a nominal fee, stompbox and all...

  8. David Wilson

    David Wilson Administrator Staff Member Administrator

    Oct 14, 2002
    Lower Westchester, NY
    Mike, sounds great.
    If you have a DPDT switch in the stompbox, it'll look like this from underneath in terms of lugs

    1 2
    3 4
    5 6

    If it's wired in a standard on/off way, then
    3 will take the signal from input jack, output from 4 goes to output jack.
    1+2 will probably be connected so you get true bypass 3->1->2->4->out with switch off
    So then 5 will go to preamp in, and 6 will take the hot preamp out signal to get the 3->5->pre->6->4->out signal route with stomp engaged.

    Does this help?

    And I could probably be persuaded to buy it from you also :)
    Like I said, even if I never use it in a bass I love to do these things as learning exercises. And at the same time, we'll be able to help Matt @ FBB out with his schematic needs!
  9. FBB Custom

    FBB Custom TalkBass Pro

    Jan 26, 2002
    Owner: FBB Bass Works
    Gracias, gentlemen.

    You should see the tangled mess that was sold to me. I'll tell you how mine is currently wired, from left to right, looking at the side of the preamp module with the label on it:

    to top left, top center of dual taper* (not dual concentric) b50k pot , respectively. The top, left lug is also wired to the top, center lug of a second dual taper b50.

    to bottom, center of b50k pot #2. This lug is also wired to lug #1 of a DPDT.

    to bottom, right of b50k #2.

    to bottom, left and bottom, center of b50k #1.

    to top, right of pot #2.

    to lug #2 of the DPDT (numbered as in David's post).

    wired to a slider of indeterminate load. The slider has 4 lugs, and in between them is what looks like a caterpillar, but is actually a load of caps and resistors wrapped in electrical tape. The lug is marked #1.

    goes into the caterpillar and attaches to an unknown location.

    attaches to lug #3 of the slider. this lug is also wired to lug #2.

    to battery, 9V

    to ground (unconnected).

    To round out the wiring of the DPDT:

    lug 3, unconnected wire (probably signal out to jack).
    lug 4, connected to lug 3 of A250k (volume).
    lugs 5&6, connected (this is a preamp bypass switch).

    lug 2 of volume is red, disconnected (signal in)
    lug 3 of volume is black, disconnected (ground).

    * - the pots in my harness are ganged, meaning there are two pots stacked, but only one post (not dual concentric). The post turns both wipers simultaneously like a blend pot. I do not know if the tapers are reversed like a blend pot or not. If the pots are indeed supposed to be dual concentric (and not ganged dual taper like mine), then Aguilar has those.
  10. Matt: Sorry--yes, mine has ganged pots as well, not concentric. I just totally blanked out on the term!

    What I expect is happening is that ther regular setup has the second ganged pot substituting for your sliders. Tonight I'll compare the wiring you posted with what's in mine. I believe I only have 9 wires coming out of my EZQ, but it's a rather old one.

    david: The switch is a SPDT, I think, since there are only 3 posts on it. Once upon a time, I actually used know more of this stuff, but I've gotten pretty rusty in the last 15 years or so. But if you want this thing, shoot me a PM and we'll talk.

  11. David Wilson

    David Wilson Administrator Staff Member Administrator

    Oct 14, 2002
    Lower Westchester, NY
    ok, looks like I'm going to buy whatever Mike has whether it's working or not and I'll have a rummage around.

    Hopefully between Matt and I we can then reverse engineer a schematic from Mike's stompbox.
  12. Well, the EZQ works, though it's a bit crackly and cuts out--the jacks need cleaning and there are probably a couple of loose solder joints or something. But here's the wiring:

    BLUE -> top center, pot1

    BROWN -> top right, pot2

    WHITE -> top left, pot1 -> top center, pot2

    BLUE -> bottom center, pot1

    WHITE -> bottom left, pot1

    RED -> battery clip

    BLACK -> input jack, middle lug -> battery connector

    YELLOW -> input jack, tip lug -> SPDT lug 3

    GREEN -> bottom center, pot2 -> SPDT lug 1

    PURPLE -> bottom right, pot2

    SPDT lug 2 -> output jack, tip lug

    input jack, ground lug -> output jack, ground lug

    *-pots: top = furthest from shaft

    *-Switch lug arrangement:


  13. stroy05


    Feb 21, 2001
    Houston, TX
    Endorsing Artist: Callowhill Guitars, Aguilar Amps, JHAudio
    What ever happened with figuring this out. Did you guys get them working?
  14. David Wilson

    David Wilson Administrator Staff Member Administrator

    Oct 14, 2002
    Lower Westchester, NY
    Mike sent me what he had, in the meantime I sold the bass I had been thinking about putting it in.

    So it's been sitting there doing nothing for a while. If you want it, I'll send it on to you for price of postage.
  15. evilgus

    evilgus Supporting Member

    Feb 27, 2006
    Sydney, Australia
    Noticed last night that the EZQ seems to be back in production, as Best Bass Gear has them listed as In Stock. There's also wiring diagrams and info on it, could be handy!

  16. Thanks Evilgus - I Just ordered one! I'm sure they won't last long.
  17. Hey Metro, please tell us how it is, I'm really interested. :D
  18. evilgus

    evilgus Supporting Member

    Feb 27, 2006
    Sydney, Australia
    Not sure I'm prepared to pay US$50 for shipping to Sydney, have asked about that! :)

  19. $50! Shipping has gone ridiculous... Although, I just paid about $60 to get an iGIG shipped here :D I guess sometimes you get lucky..
  20. evilgus

    evilgus Supporting Member

    Feb 27, 2006
    Sydney, Australia
    I better clarify that the US$50 shipping is actually for an Aguilar Tone Hammer plus an EZQ. I enquired about it and found out the TH is actually quite heavy, hence the cost. Haven't pulled the trigger yet, as I'm not 100% sure those short-shaft pots will fit a rear-routed bass. (Plus the Tone Hammer has sweepable mids anyway, so almost overkill to get both items.)


  21. Suresh


    Apr 15, 2007
    I had a Tone Hamer,and its sweepable mid is really useful!!

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