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"Stereo" bass wiring.

Discussion in 'Pickups & Electronics [BG]' started by kurosawa, Jun 4, 2012.

  1. I want to build a 2 pickup bass wired "stereo."

    This has nothing to do with right and left channels; the essence of this idea is simply to EQ each pickup independently before mixing.

    I guess I could use this Rick-O-Sound schematic:


    That is the standard scheme, to have a separate output for each pickup leaving the bass.

    Or I could EQ each pickup's signal and mix them before the signal leaves the bass.

    That would call for a survey of available onboard EQ/preamp circuitry, and would require a new circuit design. Appreciate your ideas.
  2. Stealth


    Feb 5, 2008
    Zagreb, Croatia
    For one, it depends on whether you want to go active or passive.

    Going passive won't be a problem - the Ric-o-Sound schematic is simple enough, although it's not the most elegant solution there is because you have to have a dedicated stereo and a dedicated mono jack. Going with two mono jacks is simple (that's how Billy Sheehan did it), going with two jacks that behave in stereo when both cables are in is a bit more complicated but much more convenient.

    Going active will be a bit of a problem because there aren't many dual-channel preamps (with independent EQ stacks for each channel). The usual approach with preamps is blending first, EQ next, and the blending stage is usually passive. Unless the pickups themselves are active there will be interplay between pickups, so you might have to actually fit two separate preamps in. Shouldn't be a problem if you want two MusicMan Stingray preamps as they're physically very small and fit just about anywhere.

    An alternative idea is to just use two simple buffers (preamps that only act as voltage followers, so you get no tone loss from long cables) and EQ the signal down the chain, using pedals or the amps themselves.
  3. SGD Lutherie

    SGD Lutherie Inactive Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    I've been wanting to put two preamps in one of my basses, one for each pickup. I think that's a cool idea, and then the two sounds can be blended.

    I played Rics for many years, and the stereo option seemed cool at first, but got to be a pain, especially when I would forget my cable. At one point I ran each pickup thorough a 10-band graphic EQ.

    For a nice compact 2 band EQ you can't beat the EMG BTC.
  4. mikezimmerman

    mikezimmerman Supporting Member

    Apr 29, 2001
    Omaha, Nebraska
    Bartolini used to make a dual two-band preamp, with separate bass/treble controls and mid-contour switch for each pickup. It's what the original Tobias Growler basses and Zon Sonus Studio basses had. I don't see it in the Bartolini catalog anymore, but Zon describes the current preamp model in the Sonus Studio as the Bartolini "ZB6".

    Though it was exclusive to his basses for a while, Alan Cringean (ACG) has started selling his EQ-01 preamp separately. It features separate lowpass filters for each pickup, similar to the Wal and Alembic Signature setups.

    Neither of these is really a "stereo" setup, since they both have mono outputs, but they do allow you to EQ each pickup independently.
  5. Skelf


    Apr 15, 2005
    Moffat D&G Scotland
    Builder AC Guitars.
    I built a seven string with a separate ACG EQ02 pre-amp for each pickup but it still used a single volume/blend before going to the jack. Not stereo as such but fully independent EQ over each pickup.
  6. xk49w


    Apr 13, 2008
    A Tractor replica has a single stereo jack and a push/pull tone pot to switch between a single channel output (all p'ups in parallel), and two channel output (Darkstar to one output, jazz p'ups to the other).
  7. I think what you're wanting is more like "2 channel" rather than "stereo", right? Just making sure I have it understood properly.

    Why can't y'just run each pickup straight out it's own jack and then do all of your electronic trickery off-bass? Pipe each pickup out, plug in to your own custom mixer/preamp gizmo somewhere in a rack, on the floor or desktop. Maybe just use two mic-pres feeding two active preamps (shoot, two PODs for that matter) into a 2ch mixer (Mackie has one for like $100). Just use individual volume controls on the bass to adjust the mix (Billy Sheehan again here.)

    So run each pickup into it's own mic-pre (so you have some gain-structure control) then run each pickup into it's own POD, then mix them via 2 channel mixer, then amplify the works. If you go used that rig would cost around $300. And talk about versatile! Using a "two channel rig" like this the possibilities are boundless. Use a panning footpedal to sweep between pickup channels.

    I don't do anything like this at all. Not at all .. ~ahem~ .. ;)
  8. The attraction of EQing and mixing on board is having one output earlier. But it's more flexible if done after the bass. I might want to try both.

    I noticed that these days, "two channel" may NOT mean both channels are accessible. Some devices switch with only one active at a time.

    I just bought this tube PA head http://www.ebay.com/itm/261034083836 to get a second channel. It also has channels for other basses.
  9. Excellent point. Thank you for adding that to my brain!!
  10. Outboard EQ seems most flexible. The cheapest fix I could dig out of my junk box is a K&K Power Pack: volume, treble, bass. I could plug one pickup into it then into a second jack.

    But I now have a couple of AIMS 4-channel tube PA heads inbound. They were designed to run a pair of 6550 tubes at 102w RMS. Most 6550 tubes won't go there. The Magic Tubes cost $2-300/pr. Less magic, like 80w, costs $100/pr.

    I'll see how well they're tubed when they get here.
  11. When I read stuff like that I don't feel so bad for spending $1k on the six-filter modular setup I use. It's made from modular synthesizer variable state filters and is ridiculously flexible as well as 100% analog. My latest trick has been to use that rig to allow me to switch pickups with a sweep-pedal. Run each pickup through it's own set of 3 filters (a HPF, a NOTCH, and a LPF for each pickup) then sweep between each dedicated filter bank with a sweep pedal. So far so good. And 1/4th the cost of using two SVTs to biamp with (using a Mackie 1400i as power). Maybe someday I will be able to afford two separate bass cabs to go along with this rig. But total cost so far including the power amp is $1600.

    Maybe someday add a couple of 1x15s or perhaps a 1x15 and a 2x10 ... killa cooly!

    More info as it develops.
  12. Oh yeah, the magic is in the filters! Well that's a whole other stage of the game. I painedly remember passing by a dirt cheap Alembic stereo filter preamp on eBay before I knew what it was. Well, maybe another one will float by in the future.

    Is yours a standard filter setup or a homebrew?
  13. Six of these ...


    They require a special power supply too ...


    And a wiring loom to rout power to them ...


    You also need some sort of preamp (like a mic-pre) to get your bass signal up to the 5 to 10 volts this stuff is looking for. I use a Presonus Tube Pre and a an ART tube pre... they work just great for this purpose. So you plug your bass into the mic preamp, then go straight into the first filter. You may then rout the signal in series, or parallel, or even a hybrid of series/parallel if you are setting up a filtering structure that requires it. Just start plugging in patchcords! In the setup I'm making currently I'll have five sweep pedals that will alow me to sweep between pickups on the fly, as well as adjust the frequency centers and resonance for the filter banks for both/either pickup. This solves a ton of issues that have bugged me about electric basses since day one. Namely the way that if you get the E and A strings to sound nice and tight the D and G strings sound thin, and if you fatten up the D and G strings then the E and A strings sound flabby. So this rig will allow me to revoice the filters and the pickup balance almost-but-not-quite as fast as the music flows and I change which pair of strings I'm playing on. All with my feet. So to get that done I have a couple/few of these coming (it's a control pedal interface, very capable stuff) ...


    When you use this stuff you also need some way to mount them up. Like a rack with adaptors or purpose-built cabs. Here's my rig when I first started messing with it. I didn't have any rack adaptors so I made some temporary ones out of 1/2" oak trimstock and painted them with pickup truck bedliner....



    Since then I've aquired two purpose built cabs and I'm currently in-process of getting them done-up. Again with the bedliner stuff .. I just dig using it!...





    I near completion more and more every day. Some people may scoff at the cost and hassle. Frankly it costs far less than biamping would be if I used a pair of SVTs or a pair of just about ANY dedicated bass amps. I'll have around $1250 in the bi-filter-rig and $250 in the Mackie. Said and done I'll have a full blown hyper versatile bi-filtered bass rig including loaded speaker cabs for ~less than~ $2500. And it'll have more capability than any bass rig I have ever owned, or even seen for that matter. These filters sound friggin awesome and are fully adjustable, have four different filter types in each module (LPF, BPF, Notch, and HPF) .. you can mix the types, or use them singularly. Each filter has self-oscillating resonance so you can really "voice" the filters to your heart's content. And any knob is adjustable via control pedal or you can use an LFO to automatically sweep the function. I have two lfos as well. I learned all this stuff during 30+ years of playing analog synths.

    You can learn more at Synthesizers Dot Com. That's the company that made the stuff I happen to be using, but there are piles and piles of manufacturers of this stuff these days. In three different formats as well.

    Ok, I'm done giving up all my secrets.. :) Hopefully I'll be able to provide some sound clips soon so that others may hear what this stuff sounds like.
    Steve-Mo likes this.
  14. That is AMAZING. I see a Cort on your profile. So is it wired stereo? I hear you about the differing density of string sound from low pair to high. Have you been GASsing for P pickups or pickups split EA/DG internally? Or have you found a magic string combination? You're making Jack and Phil look like pikers.
  15. No magic string combos, that's why I had to come up with the whacky 2-channel filtering setup with a panning foot control to allow me to quickly pan between pickups to deal with the string pair issues. I did some hack-wiring on the CORT to provide dual signals as a simple proof of concept prototype. However currently I'm doing the same thing as the OP ... building a two-output bass that will be used with the filter banks. I'm still working out the gnarly details/pickup selections/pickup placement/and so on, but it IS happening. Just going from the pickups to individual volume controls, simple individual tone rolloffs and striaght out to the filter banks. No internal EQs or preamps. All tonal shaping is to be done with the filters as well as foot-controlled pickup selection and mixing.

    Thanks for the encouraging remarks! :)
  16. SGD Lutherie

    SGD Lutherie Inactive Commercial User

    Aug 21, 2008
    Bloomfield, NJ
    Owner, SGD Music Products
    Why on earth would you bi-amp with something like an SVT?

    I had one of these once. It's bi-amped right out of the box:


    Built in crossover, 300 watts to the bass cab, 100 watts to the high cab.

  17. Why not? Geddy did. He used Sunns and SVTs together. No crossover. The bridge pickup was sent to one of the two heads, the neck pickup was sent to the other head. In-friggin-credible live sound.

    And I find it very hard to accept that the GK would do what the rig I've set up will do. Can it be swept between pickups with a foot control? Does it allow you to control the resonance of each band? Something that if some bassists ever tried they'd never go back to "fixed freq EQs". Adjustable resonance is something that totally sets how the eq band is "voiced". Not to mention full-on filter type and frewquency control. There's simply no comparison.

    I've owned many many bass amps, and this new rig is something I wished I'd had decades ago (and easily could have, these same synth modules have been around since the late 1960s). The versatilty is ridiculous and since it's modular if one module goes down I still have the entire rest of the rig to continue on with. Each filter is only $136. Or if the power amp goes down I can replace it overnight with about $250 spent. And so on. It's the ultimate modular bass amp. But I realize "modular amps" aren't hip these days. I'm not much on "hip" though .. never have been.

    I'm just at that stage in my bass life. Wanted something completely tweakable and custom.
    grouse789 and Steve-Mo like this.
  18. ShaunNecro


    Aug 1, 2007
    Houston, TX
    I have my Jaguar Bass wired stereo with my neck pickup going to one amp and the bridge to anyother. I haven't had the chance to use it in a band setting yet, but it kills right now! I have it wired with a stereo jack, then use a y-cable to split both signals into a Voodoo Labs Amp Selector, which then lets me split both signals to two outputs each. It was pretty easy to do, and absolutely worth it.
    grouse789 likes this.
  19. xander8280


    Dec 29, 2011
  20. Killa ...

    I was thinking of going with two N/C switching jacks with the N/C terminals wired together ("N/C" means "normally closed").

    When only one is used you'd have a mixed output just like any ~mundane~ bass. ;)

    When both are used you'd have 2-channel output. :)

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