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Preamp Customisation?

Discussion in 'Pickups & Electronics [BG]' started by daveze, Sep 2, 2003.


  1. I'm in the process of finalising my plans for a bass I'm going to make but I have a few questions regarding preamps.

    I'm considering using either an OPB-3 or a U-Retro, as I've heard they are both very good setups (a Bart setup is a possibility if someone can convince me that it will be good). However I want to know about a few cusomisations I want to make. I want the complete setup to consist of: Volume, second volume/blend (one or the other), BMT cut/boost, the ability to select the mid freq (switch with a few settings or sweepable, though I'm leaning towards the switch for ease of use), passive active switch, and tone knobs for both pups (though I will settle for just the one, reluctantly).

    I've been researching a bit of stuff, downloading various wiring diagrams from the respective sites, checking a bit of other info, etc. Both systems will come close to offering what I want but with out a few things, like the tone knobs or the switch for the mids, that kinda thing. I want to know if its possible wire in what I want to have in there. I can figure it out in theory, partly through it now but not sure if I can actually do it, having never seen either system in person (the dealers for both are in different states, neither in the one I live in).

    Yay or nay? Is it worth it or am I about to end up with a million knobs, of which, the volume and blend being the only ones used?

    And a reccomendation on pickups to compliment the setup? I don't really know what sorta tones I want to get from them, so maximum versatility. Cost isn't a huge issue (I'm going to take as long as necessary to complete the bass, so money will be flowing in for purchases as needed) but I'm not forking out for set of Aeros that will be worth more than the rest of the components combined. I did consider winding my own but I think I'm gonna leave that for the next one.

    Josh D
     
  2. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    OK, a lot of questions here :)

    From what you say, the U-Retro Deluxe will get you further to your goal out of the box. It has a single passive tone control, plus mid freq sweep.

    Putting two tone controls in with a regular U-Retro system would be possible, though you'd have to wire the tone controls pre the U-Retro input section. The U-Retro has an active blend section, and both pickup signals get wired into the U-Retro input. So you could have u-retro deluxe with one passive tone, or u-retro and wire in T/T controls pre the input stage. In this setup, each T control output would then go to the respective input on the U-Retro rather than in a T to T chain like in usual systems.

    The OBP-3 also gets close to having what you want out of the box also, although you have to do more soldering yourself rather than getting the preassembled preamp that is the U-Retro. The OBP-3 doesn't have any built in blend features, and can take the output of whatever V/V/T, V/T/V/T, V/B/T configuration you want to wire together.

    Possibly. I like on board flexibility, but I also try and keep my choices down because if I have 8 knobs to use I'll use them, constantly. I can see where individual tone controls would come in handy, but as an inveterate fidgeter they'd probably be too tempting for me and I'd end up playing with them as well as all the lovely bass/treble/mid/mid freq/blend/vol stuff.

    As for pickup recommendations, I think we'd need more info on the bass you're building - woods used, style, sound you're looking for etc
     
  3. Thanks David, I figured it wouldn't be that complex, I was thinking a pretty similar approach myself.

    The bass will be a 6er fretless, ebony fingerboard, maple and kirra (stiff Aussie hardwood) neck laminates (maybe another bubinga/wenge/purpleheart depending on whether I can get a piece for a good price), Sapele body wings, hipshot A style bridge. I think that'd be the most important stuff about the bass. I play at a church, so I'm a bit more restrained but we're going to form a more 'bandlike' band at some point...

    For the pickups I want to be as versatile, until I figure what sort of sound I want to have.

    Josh D
     
  4. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    re: the pickups.
    Active/Passive?
    Soapbars/J's/PJ?

    I don't know what selections you have available to you there, but I'm assuming they're all expensive as US made pickups will have to be imported. So, your cheapest / good quality options will probably be EMG/Bart/SeymourDuncan.

    Barts are usually described as 'organic' sounding. I hated them in my Warwick Thumb5, it was a very woolly sound, yet they sound great in my Elrick 5.

    EMG's are about as inorganic as it gets, very bright and punchy, I do love that sound in certain circumstances.

    I think Seymour Duncan are the best volume produced pickups, they're a good middle ground between Bart and EMG.
     
  5. Again I say thanks. I was leaning towards the Duncans, without any reason though.

    I can get ahold of Seymour Duncans reasonably easy, I'd have to order them in though. Nearly every store locally only has like a total of 4-5 sets (at the most), and thats for both guitar and bass. But I can get pretty much everything in.

    I want soapbars but I don't mind active or passive, however, if I was going to go actives (EMG for example) wouldn't that mean that wiring the electrics would be weird. Because the pickups need power, and so does the pre, so with my passive/active switch, it'd have to be wired so that theres always current powering the pups. I don't really understand exactly how active pups work in that respect...or will active pups need powering even with the preamp running?

    Josh D
     
  6. christoph h.

    christoph h.

    Mar 26, 2001
    Germany
    I'm not sure whether this is an option for you, but mike pope (who designed the fodera preamp and is a *great* player) offers custom-built preamps.
     
  7. I hadn't really considered Mike.

    After brief some consideration, I don't think it'd work too well. I'd have to probly pay a lot more and it'd be a real sod to get down here as well. The bass as a whole is going to be one big learning experience, this I figure will just be one part.

    I remember reading the specs on the Fodera pre and I was real impressed by it, maybe when I get a bit more money and/or make it to the US.

    Josh D
     
  8. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    The SD soapbars are active. Bart soaps are passive.

    If you have active pups then your active/passive switch essentially becomes a preamp bypass. If you have pups and preamp powered from the same battery/batteries, then it won't help you in the event of battery death. You could wire two battery circuits, so the pre gets 9v and the pups get 9v individually rather than them both sharing a series 18v.
    It's been my experience that when you have active pups and preamp you do start to run into headroom issues with 9v only.

    Also, an active/passive switch doesn't usually switch off the preamp but just removes it from the signal loop. It will still be getting power as long as the cord is in the jack completing the circuit.
     
  9. Sweet as, thats exactly what I wanted to hear. I think I'll go for the single power circuit, keep it simpler and theres less to stuff up.

    Thanks again.

    Josh D
     
  10. Dude

    Dude Commercial User

    Mar 19, 2000
    AZ
    Owner: The Dude Pit Forum (closed) Producer: School of Bass
  11. hands5

    hands5

    Jan 15, 2003
    good 'ol USA/Tampa fla.
    none
    DITTO !.I just put a Mike Pope preamp in my Tobias Basic 5 and I'm just smitten" on how good this damn thing sounds.Now here's the kicker.I'm real,real tempted to put one in my MTD 635 !This is a smoking preamp.:oops:
     
  12. Moo

    Moo Banned

    Dec 14, 2002
    Oakland, CA
    You can get all the features you want with a Bart preamp. All the add ons you want are just simply adding a switch or tone pot in the right place. Since you have to wire your own pots with a bart it won't be any harder just more complex.

    Also a GREAT humbucker for fretless is the Ken Smith soapbars. Very agressive without being too bright and if you add series parallel switches (if you have room for two more) you have an extremelly wide palette available. These are famous for their fretted sound but they are just insane on a fretless.

    And to fill the faceplate of your bass even more, look at the 4 coils of 2 hummers lined up from bridge to neck as coil 1&2 then 3&4. You can set up a switch so only coils 2&3 are on giving you a really wide aperature humbucker or have 1&4 on and a really really really wide humbucker like both pups full on on a jazz bass. In this mode it's like single coils on a jazz bass and panning to one side will add hum.

    How about two Smith humbuckers leading through a series parallel switch and tone roll off, then meeting at a passive pan pot and volume and off to a switch to send it either straight to the jack or into a 3band EQ. That's a lot of tone control before you even touch the active stuff :)

    Things like the midrange freq. selctors you may want to wire up inside the cavity just to retain a bit of modesty ;)