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  1. #21
    Quote Originally Posted by Ross77 View Post
    How dose that pick up work? if I may ask. coil winding is next on the list of machines to build. after mill, router, raduis machine and inlay cutter....

    Are each of the coils feed back to amp/processor individualy or are they conected in series for better string balance?

    Sorry to interupt the thead..
    No probs...I've been scant with the details because after all, this is more of a mechanical-centric forum than an electronics forum. The small coils I intend winding aren't actually pickups (I used the term as it was simpler!).

    These coils will actually be sustainer coils. The intention being to keep the guitar strings sustaining as long as the player wants them to. It does this by tapping off the guitar's standard pickup output signal, amplifying it & feeding the signal into these coils...this creates a varying magnetic field...& the guitar strings are ferrous so react to the mahgnetic field.

    the coil is the easy bit...the tricky/creative bit is coming up with a good circuit to drive the coils!

    re the pickup winder...it really is a heath robinson, but essentially it's a main motor, with an encoder disk mounted on iT (a CD label containing a lot of black/white stripes). I created an electronic circuit to synch the main motor with a stepper motor (buy counting the black stripes). It's via the shaft of the 'synchronized' stepper that the enamelled copper wire feeds onto the coil core.

    Because there is so little room to fit my sustainer device (I don't want to route the guitar body), I reckonedthat the only way forward for these coils was to go bobbinless (coils/pickups are normally have a bobbin, upon which the copper wire is fed onto...but the bobbin itself takes space). That's when I had to throw open my plight to this forum...Dean kindly offered to get involved & help out.

  2. #22
    Sounds good, at last a fellow guitarist.......
    Maybe Lee will open a musical instument section so we dont bore the rest.....Building guitars and related parts is is main reason for getting in to cnc.

    Not able to help yet tho as not properly setup.

    So is this basiclly causing the strings to vibrate like feedback?

    BTW always found that a Marshall on full tilt driving a 4X12 is good for sustain.....:dance:

  3. #23
    Quote Originally Posted by Ross77 View Post

    So is this basiclly causing the strings to vibrate like feedback?

    BTW always found that a Marshall on full tilt driving a 4X12 is good for sustain.....:dance:
    Yes...that's right, but this is somewhat more neighbour friendly (with no ASBOS received ...except maybe for the incessiant whine of my clunky DIY CNC milling me some guitar bits & bobs!)

  4. #24
    Yes...that's right, but this is somewhat more neighbour friendly (with no ASBOS received ...except maybe for the incessiant whine of my clunky DIY CNC milling me some guitar bits & bobs!)
    Dont have that problem, nearest neighbour is a quater of a mile away
    Thats probably why I'm deaf..:surprised:

    Wot geetarrs have you got?

  5. These coils will actually be sustainer coils. The intention being to keep the guitar strings sustaining as long as the player wants them to. It does this by tapping off the guitar's standard pickup output signal, amplifying it & feeding the signal into these coils...this creates a varying magnetic field...& the guitar strings are ferrous so react to the mahgnetic field.
    Do you even need a magnet?

    A magnet is required in the pick-up (the pick-up is actually a reluctance sensor) since the strings are not magnetic (i.e. they don't produce a flux). However, to vibrate the string surely only requires a varying magnetic field which could be produced with just a coil and a suitable pole piece. The effect of your magnet is to produce a strongly biased field - I can't see how that helps to produce the drive you require.

  6. #26
    Quote Originally Posted by BillTodd View Post
    Do you even need a magnet?

    A magnet is required in the pick-up (the pick-up is actually a variable reluctance) since the strings are not magnetic (i.e. they don't produce a flux). However, to vibrate the string surely only requires a varying magnetic field which could be produced with just a coil and a suitable pole piece. The effect of your magnet is to produce a strongly biased field - I can't see how that helps to produce the drive you require.
    Yes, I thought the same when i started out on this journey, but you do need a magnet (& believe me I've tried just about every permutation).

    You can think of the magnet along the lines of DC biasing in electronics terms (best comparison I can make). The guitar strings aren't 'magnets' ...just ferrous material, so the sustainer coil can only pull on them (& release)....that is, the sustainer can't "push" the string away from the coil. By having a permanent magnet, you can then have a slight quiescent pull on the string & then when the AC guitar (drive) signal is added into the mix, you're effectively getting a pseudo pull/push effect (on one half of the AC signal the permanent magnet's quiescent 'grip' on the string is relenquished which is like a pseudo-push...& then the other half of the AC signal the permanent magnet is given a boost, forcing it to pull stronger than in its quiescent state) ...it's difficult to explain in the written word, but yes, you really do need a magnet.

    The other option would be to apply a DC biasing current through the coils (ie dispense with the permanent magnet - just a pure solenoid) .....the problem with this method is it'd draw too much current....& power is scarce on a guitar (such guitar circuits normally being driven by 9V PP3s, which are only 500mAH at best)

  7. You can think of the magnet along the lines of DC biasing in electronics terms (best comparison I can make)...<snip>
    Ah yes, that makes sense. And, thinking about it some more, is why old type telephone speakers, that were a spring-steel plate suspended above a coil & magnet arrangement, had magnets in them.

  8. #28
    you can then have a slight quiescent pull on the string
    Isnt that going to give you tuning and intonation problems like when a Pup is set to high? :surprised:

    Where dose this go then? since it looks like a single coil are u lossing a pickup to use it?

  9. #29
    Quote Originally Posted by Ross77 View Post
    Isnt that going to give you tuning and intonation problems like when a Pup is set to high? :surprised:

    Where dose this go then? since it looks like a single coil are u lossing a pickup to use it?
    Well this is how the commercial ones work too!

    in practise I don't see how it could it would cause much in the way of problems (if your guitar's intonation is setup up right, then it'll cause no impact whatsoever. After all, that's what setting up intonation is about....so the tuning isn't knocked out of whack no matter where you fret the string) ...& we're talking minimal quiescent pull. Where you have to be careful is on the guitar's natural sustain (ie no sustainer active)...if the sustianer coil magnets have too strong a pull on the string when inactive, it actually kills the guitar's natural sustain.

    re mounting....well, the commerical ones, you have to sacrifice a pickup...but I'm trying to get a surface mount one to work (hence the low height). These sustainers aren't suitable for all guitars as normally they do radiate a lot of magnetic interference, which alas is the very thing a guitar pickup senses! Therefore it certainly needs some physical distance from the next nearest nearest pickup.

  10. #30
    Ah. I see. sounds like a good project.

    Is it the no.of turns and length of wire that makes it work? If so you could use a small square bobbin to reduce the wasted space between the coils and then you can drill them to suit the size of the magnet. no need for a fancy holder and hopfully reduce the height.

    Just my 2 peneth

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