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3 pickup pre amp?

Discussion in 'Pickups & Electronics [BG]' started by Thunder_Fingers, Sep 21, 2004.


  1. Thunder_Fingers

    Thunder_Fingers

    Jun 24, 2004
    Norway
    Anyone know about who makes an onboard preamp for 3 pickups? im planing making an bass with 1 Seymour duncan Quarter pound pickup and 2 Bartolini Rickenbacker pickups..(or just their regular soapbar pickups..most probaly rickenbacker pickups..)
     
  2. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    Haven't messed with preamps in a while but you only have one lead that feeds the blend which just uses a jumper for a pair of pups and the lead feeding the volume and blends were interchangeable in wiring onboards to outboards. Can think of no reason offhand you couldn't jump for a third pup. But don't know and have never done it.
     
  3. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of E-Pro & East UK
    Here's a way I've done it in the past for U & J-Retros.

    First important to note that the Retros have individual buffer amplifiers, one for each of two inputs, which helps matters here.

    So for a bass I've been playing around with, which has two jazz style single coils and a MM style humbucker:

    * Have an additional passive blend between the two single coils where the output feeds one of the Retro inputs.

    * Have the MM feed the other input.

    So the Retro blend pot goes between the J pickups mix and the MM and the additional blend sets the mix of the Js.

    This allows totally flexible mixing of all combinations.

    John
     
  4. Thunder_Fingers

    Thunder_Fingers

    Jun 24, 2004
    Norway
    Ok, that might work, but.. i have no idea what you talk about :crying: i had probaly killed 5 preamps before i got it right... :meh:

    *does Fender Sell the Preamp they used for the Stu Hamm sig.?* :p
     
  5. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of E-Pro & East UK
    My understanding is that there's a lot of comprehensive pickup switching in the Stu Hamm rather than a specific 3 input pre.

    John
     
  6. Thunder_Fingers

    Thunder_Fingers

    Jun 24, 2004
    Norway
    huh, is it possible to get like a wire from each pickup going into one volum knob each, and from the volum knobs one wire from each that goes into one wich when it goes to the preamp? (with 3 tone configurations. bass, Treble and Mid.would that involve a lot of Work? :p

    i know there will be many comtrols on it though, and the bassim planing gonna have an warmoth Dinky p Carved Body of mahogny and Flame Maple top...
     
  7. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of E-Pro & East UK
    Yes, but to do it you'd ideally need a proper mixer stage with a least 3 inputs, then the EQ of your choice.

    Not intending to go commercial here just show that the stuff is around to do what you want, but I have something which would do the mixing, but it has a piezo input stage too, which you don't need. (MPB-01 which has piezo input stage and 4 input mixer)

    John
     
  8. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Was wondering what you mean by "killed?" I've wired preamps every wrong way imagineable and never damaged anything.

    Also, like I said, it's been a while but I just skimmed through some diagrams and two volume controls on a preamp instead of a volume and blend just use jumpers from volume to volume so why not three. You may get some impedence mismatches depending on the pups you use and I suppose some eq would be ideal but seems it should work fine regardless.
     
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Eddie... I have an Urge I (more on that in a moment). I really like John East's suggestion...

    I've never used a Retro preamp to know how buffered pickups interact differently from passive ones but the idea of two blends is a great one. Actually, having typed that sentence, I guess I do know how buffered pickups interact because I have EMGs on my J5...and they sound great.

    Anyway, back to the Urge. As you know the Urge has two Js and a P. Controls are Volume, Balance (pan), Bass, Treble and a four position switch for passive (yuk (bass control acts as a passive tone control)), active, active with (internally adjustable) mid boost and off. Plus a three position mini switch for pickup selection.

    The Balance control simply pans between the Js the mini swithc allows for P only, Js only or P + Js.

    I like John's two pan idea. I guess it would take a joy stick to pan among three pickups...that would be cute!!!!

    My Urge isn't my main instrument and I usually leave all three pickups on and vary the tone by slightly moving the pan control gently favoring either the Jneck or Jbridge but neither one full on...

    You certainly could go with three volume controls, just wire them like on a Jazz Bass (pickup hot to the center terminal, etc.). If you did that, perhaps it would be a good idea to use 500K ohm pots rather than 250K ohm units to minimize loading.

    At any rate, it sounds like a fun project!!!
     
  10. Thunder_Fingers

    Thunder_Fingers

    Jun 24, 2004
    Norway
    any websites where i actually can read about stuff like that? :p

    oh, and if i just use on of swiches for the pickups? so it gets kinda the look of the G&L 2000 knobs(but far from somthing like it :p) so i can switch the pickups on and of before it goes into the preamps then? but i still needed 3 inlines(???) how about.. 1 from the two rickenbacker pickups and one from the p bass pickup... that way i can have an 2 pickup configuration..? oh, this is gonna be expensive.. i probaly must out with about 1500 for everythin minus the Pre Amp...
     
  11. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    I had a Charvel bass with PJs and a Les Paul type pickup selector. With two pickup basses, I generally have the pickups just shy of equal so I was never happy with the P + J position of the switch.

    My point is that if it was my bass, I'd want to be able to blend the various pickups together not just switch them in and out. The three volume control method should work just fine.

    As far as needing three lines goes...if you have three volume controls, the "output" of each of the three controls would be tied together and then connected to the input of the preamp.

    If you look at a site like Bartolini's there are usually lots of wiring diagrams. If you find one for Jazz basses with two volume controls, just draw in a third just like the other two and that's what you'd be doing. As I wrote in the preceding paragraph, note how the two volume controls are interconnected on a Jazz bass and add a third. Nothing too fancy, you're just building the wiring diagram up in modules...
     
  12. John East

    John East Commercial User

    Jan 10, 2002
    Oxford UK
    Owner of E-Pro & East UK
    If you really wanted to go mad with a joystick, where the layout is normally a stick which can directed anywhere within a square, you could pan between up to four sources, or pickups in this case. You take the stick right into the corners to hear each individual pickup.

    So far you're talking three but you could add a piezo as the fourth panning between all! Having the stick in the middle would give you an equal mix of all.

    (I think you'd need some switching to too, in order to get all combinations, where some pickups weren't required)

    More seriously though, having three volumes wired like Jazz basses might be very 'touchy' (small rotation gives big level change) near max settings due to lower impedance pickups feeding other pickups via high impedance pots. It's far from optimal with two pickups and might be worse with three, especially if they're of differing impedances.

    John
     
  13. Thunder_Fingers

    Thunder_Fingers

    Jun 24, 2004
    Norway
    well... how to get the full range of the pickups and still have one volum/on-off control for each of the pickups then? argh.. i need someone to tell "I want an pre amp like that and that" and they make it for me :p but that probaly gonna cost about 400$ :( and building one of warmoth parts + the hardware gonna cost me over 1200 already... :(
     
  14. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Am I missing something here or has this not already stated more than once:

    take any preamp wiring diagram with two volumes and add a third volume as the second was added and it will be no less full range than the two pup setup.
     
  15. Thunder_Fingers

    Thunder_Fingers

    Jun 24, 2004
    Norway
    ok,but i have no idea how to do that or anything :( of how to know where to place them so they fit the pickups.. :( and on the regular pre amps i see around only have one volum control, even if they are designed for 2 pickups...:( they just slap on an "Blend" Switch... :mad:
     
  16. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    Look at a standard V/V/T jazz basswiring diagram. Like this one:
    http://www.seymourduncan.com/website/support/schematics/jazz_bass.html

    If you look at it, you'll see that the ground wire for each pickup goes to ground, and the hot wire goes to the middle lug on the volume pot. As you turn the volume pot down, an increasing amount goes to ground (the left most lug on the diagram)

    The signal not being sent to ground goes out the rightmost lug. You'll see the signal from neck pot passes through the same lug on the other volume pot, which contains the bridge signal. So, to put another volume pot 'ahead' of those two is just a case of adding another volume pot and wiring as before - cold goes to ground, hot goes to middle lug, and the output from end lug now forms the start of the signal chain.

    This is not part of any preamp, this is basic passive wiring. A preamp like the obp-3 then takes that signal chain as input, and you then apply eq/etc. If you know any techs in your area, any of them with a basic understanding of guitar electronics could easily wire this up for you. I've described this about as simply as I can.

    As John East, numerous folks have said, blending between three pickups can be problematic and there are a few solutions that have already been described.
     
  17. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Ahhh finally, David Wilson to the rescue. :hyper: I was wondering oh great master of the wiring diagram, when you would join this thread :D

    I can draw wiring diagrams by hand until the end of time, but have no software available AKAIK to allow me to do a neat drawing.

    Perhaps what Eddie needs is a three channel buffer for his pickups before an off-the-shelf preamp. An seemingly easy task with a low noise quad op amp and a few parts. Anyone know of a good chip that runs on a single polarity supply?

    John East...am I oversimplifying the solution?

    Or, to get really crazy...if the Quarter Pounder is a P...buffer and mix in each have individually... :D
     
  18. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
  19. Thunder_Fingers

    Thunder_Fingers

    Jun 24, 2004
    Norway
    ah, im not going to understand this any way, so ill just add an Musicman Pickup.. i like the sound of them too... and then ill make an bass with an that kind of setup later on(or make... put togheter from Warmoth Parts :p)

    hmm.. Quarterpound p Pickup, musicman pickup and .Aguilar OBP3 Basic Kit with 2 Volume pre amp.. sound good? or.. i could just get one rickenbacker pickup in bridge position... :meh: