HELP!

[Boz]

I'm trying to wire a six string bass so that the volume of each string can be adjusted individually. unfortunalty i can't get it to work although i think my schematic is sound. Can someone who's good at electronics tell me if there is some flaw in the schematic I've over looked?

Schematic

[camcool]

yes

[truerussian558]

dont be a dick camcool,

otherwise, it seems fine electronics wise, if you can fit the pickups there, also the 6 knobs will be a pain in the butt to position on the guitar, but it will work, and in the future a schematic would be much nicer

p.s. on the drawing it says, 3 singlew coil pickups-one under each string, but I see 6 single coil pups.

p.p.s. is there any particular reason you want to to do this?

Edited September 21, 2004 by truerussian558

[westhemann]

yes

wow camcool,is this your first post since your suspension was over?

i see you are still as charming as ever

my advice to you...either attempt to be helpful or keep it to read only

[skibum5545]

The only problem with this concept is that each pickup is inevitably going to pick up vibrations from the strings other than the one it's there for. However, piezo (or even optical) pickups would be more isolated to the string they're intended for.

What's the failure mode? No sound? Not isolated to the intended string? Sharp buzzing? Anything more you could tell us would be helpful.

[lovekraft]

Try swapping the pickup and output wires on each pot (pickup wire to the wiper, output wire to the fixed lug) - that should isolate the 6 circuits so that each pot doesn't act as a master volume. Also, 6 250K pots is going to load that output significantly - you may want to consider using 1Megs, or even 2Megs, to minimize losses.

[Saber]

p.s. on the drawing it says, 3 singlew coil pickups-one under each string, but I see 6 single coil pups.

I'm guessing that he meant 3 single-coil-size humbuckers (like DiMarzio Fast Track) with one coil under each string.

Edited September 21, 2004 by Saber

[Boz]

To clarify i meant to say 6 single coil pickups, they are old strat pickups where the wires come out of the bottom so i can position them next to eachother. mounting them and the pots wasn't a problem. once i get them wired up, they only make a buzzing sound.

[KTLguitars]

Follow the advice from lovekraft:

swapping the pickup and output wires on each pot (pickup wire to the wiper, output wire to the fixed lug)

- that is how Gibson wire their Les-Pauls- but to 6 instead of 2 separate signals! Could be practical with a master volume right before the output jack... and try also out higher values for the pots like lovekraft says.

[psw]

I saw a picture of this having been done on a guitar (but without the individual vols) on a guitar in the shape of a giant....can't say family forum...very realistic but a little oversized for an englishman!

Also EVH had a Kramer guitar with individual panning for each string...something I think would be more usefull if you have a two channel or two amp or stereo setup...or for recording...Just a thought!

My 2 cent's...I've been working on Hex pickup ideas lately and have gone piezo.

Anytime you have magnetic pickups, transformers, motors (or even bits of metal...errr, like strings) near each other there will be an interaction...it's not simply that the vibrations of the strings being picked up but the changes in the magnetic field caused by those vibrations. By having magnets or coils (electromagnets) close together you create a combined magnetic field and any vibration occuring within it will be picked up by any sensing coil within it! So six pickup coils but one huge magnetic field! There will be differences in sensitivity depending on the location of the individual coils and strings within the fields but not isolation.

But Piezo's have they're problems too! Not only do they sense the vibrations of the strings on them but also the vibrations of the guitar as a whole and especially the bridge. It is however much easier to get isolation but then it's a completely different sound.

This of course stems from my work on Sustainer Ideas if anyone want's to check out that thread.

I have had ideas of using pickup phase relationships to subtract unwanted signals from pickups in Hex pickup systems...seems like a good idea to me but I'm not sure quite how to do it...need help

That's the sort of thing you'd need if you were hoping to say turn off a couple of strings with those volume controls

2 cent's expired

psw

[guitar_paul1]

Boz -

One thing that nobody mentioned yet is that you have the pickups s-n-s-n-s-n

In this configuration, the magnetic fields will be attracted between the magnets and no flux will get around the strings, or very little. Try:

1) putting all like poles together n-n-n-n-n-n

2) do like other poster said and put pups to wipers of pots and output from top end of pots.

3) failing success, take the wiring apart and try 1 pickup. Get it working. Then add the next and see if the signal starts getting weak. If you can get one working but it fades too much with all 6, it might be that by the time you have 6, your load impedance of 250k/6=42.5k is too low to get good sound.

4) the last alternative is to convert to active electronics, essentially putting an op amp follower after each pickup before they come together. THis will isolate them. It is a simple circuit, Forrest Mims book has all the info you need.

This is a cool idea. Allan Holdsworth is reputed to have used a hex pickup on some of his early stuff.

Another way to make a cheap single string pickup is to get a reed relay from radio shack for the coil , a neodymium magnet (small pill size) and a clipped off finishing nail for the pole piece. Push the reed relay contact capsule out of the magnet and substitute the clipped off iron nail. Put the neodymium magnet on the side away from the string.

Then you can parallel all 6 pickups and still get signal out. Or else do the op amp thing.

Good luck, and let us know how it comes out.

-paul