Re: 6 "piece" PU's


"Jon Slaughter" <Jon_Slaughter@xxxxxxxxxxx> wrote in message
news:11n9giq593tuv15@xxxxxxxxxxxxxxxxxxxxx

> Wouldn't this just add hum to the pu? i.e. you have two coils one will
> induce a current in the other... the current frequency is proportional to
> the flux frequency... the PU coil will pick up that changing flux and it
> will induce a current with that frequency into the coil?

Hi Jon,
The basic electro magnetic current would be flat DC, so no hum would come
from there. If a portion of the string's signal is fed back onto the DC
current, then the added resonance would only be created at the vibrating
frequency of the string and nothing more (in a perfect world).

> If I'm right basicaly you will introduce that frequency that the EM is
> driven at into the PU coil.
>
> Basicaly its the exact same idea as a transformer except that you also
have
> a moving wire generating another current in both wires.
>
> i.e. It seems as what you saying is that you have two coils,
> ||
> ----
> ---- PU coil
> ----
> ||
> ----
> ---- "EM" coil
> ----
> ||
>
>
> where || is the magnet(or metal since we will create an EM from it)
>
> but this is really just a transformer. And as you probably know that they
> are used to "transform" an alternating power source's "strength"...

Yes, but the primary field wouldn't alternate. The alternating field would
only be introduced on a string to string basis, and would need to be a
tightly controlled representation of the string's output signal.

> > I'm aware that the current required to drive the coils would likely
> > require
> > an off-board power supply, but this shouldn't be much of a problem if
the
> > guitar comes with a power supply box (I know, tacky, but.....)
> >
>
> Well, I think this might be the least of your problems(maybe). You would
> have to cancel that hum(if I am correct about it being there).
>
> I think this might be easy though.
>
> Its just like what a humbucker does.. except this time instead of the
> "extraneous" induced current we do it in purpose.
>
> hence you turn the coil in the opposite direction and induce the current
in
> both then add the signals together on the output. (which gives a weak
signal
> I think).

Yes, like how a balanced cable cancels common mode interference.

> or, even better, you invert the EM generated signal and add it to the
> original. It should atleast remove the fundamental. I'm not sure if there
> are any other factors involved that will cause problems.

Yes, adding a phase switch to the driving signal would yield some
interesting results as long as it wasn't exactly 180 degrees out of phase
(then you get nadda).

> It might work though using something like that. I'm not sure how much
power
> it takes to make an EM magnet though but I think I remember doing nails
with
> just a 9v(with a signal generator from DC to AC).

It should work straight off the battery too.

> > In more detail:
> > Each driver coil would have its own trim pot so the magnetic field for
> > each
> > string could be balanced to the other strings, and the supply current to
> > all
> > the strings would be controlled by a six channel VCA (voltage controlled
> > amplifier chip). This 'magnetic gain control' would consist of a simple
> > pot
> > that would send a voltage control signal to the VCA. This pot could be
> > located on-board, or off-board in a foot pedal allong with the power
> > supply.
> > The range of tone possibilities would be immense by being able to adjust
> > the
> > magnetic field strength (on the fly) I would think.
> >
> > Where things become VERY interesting is when a second foot pedal is used
> > to
> > control how much of each string's AC output gets fed back and boosted
into
> > the driving current of another pickup's electro-magnetic coil that's
> > located
> > under the same string. This control would use a string's signal to
'pump'
> > the magnetic field of another pickup, and drive the string into
> > saturation.
> > Tone filters could be added to the 'insert' signal to enhance the type
of
> > feedback desired.
>
> hmmm. Maybe. I can't imagine off hand exactly what the result would be
but
> it might end up with some interesting results. Maybe one can use it simply
> for increasing sustain though.. Maybe to much would just result in a
> feedback mess.

I'm sure that would be the case at a certain point!

> Have you tried to work out the theory of it? I would be intersted in
> knowning the outcome but I don't think I could handle it at this point. I
> haven't done much electronics in several years and never was that great at
> AC stuff. (Although it was never the math so much as just having
experience
> with it. And all my knowledge/experience was basicaly theoretical since I
> learned it in class.).

I tend to avoid the math as much as possible, and go straight to
breadboarding if I can.

> > I know it might sound complicated, but the electronics are not. I
thought
> > of
> > doing this *quite* a long time ago, but other things happened and made
me
> > quite busy :)

> I think I get the big picture but at the moment I can imagine exactly what
> the result would be. It seems to me that in the first part you would be
> increasing the magnetic strength of the pole which should increase the
> induced current into the PU coil(but would also induce a current into the
EM
> coil too, but won't matter). By feeding that signal into another EM coil
on
> some other PU then you effectly are increasing that PU's strength by using
> the other PU.
>
> i.e., if I understand correctly if you play a note it will be picked up by
> one PU and the more its picked up it will drive the other PU even more.
But
> its not a constant drive since it depends on the amplitude of the
note(which
> decays ofcourse).

> What I imagine is that you will get a very "punchy" sound. Instead of
> simply exponential decay(if thats what it is), it might be something that
> decays much faster.
>
> (but thats assuming the original note decayed exponentially).
>
> I might try to work it out though just to see.

That's the fun of it all, as long as you don't blow up your basement!

> > Jon, Mattia, others,
> > thanks for posting and re-kindling my interest in pulling this concept
out
> > of the mothballs. Most likely, it would take a community effort to put
all
> > the bits together, but that's why I had no problem with sharing the idea
> > here.
> >
>
> heh. Cool. Its fun stuff to mess around. I think there are all kinds of
> ideas. Its jsut a matter of getting the ones that aren't patented ;)
>
> > Clifford,
> > I don't know if you've read all the patents you mention, but if so, have
> > you
> > seen this anywhere, or is it completely nuts?
> > (Comps & consulting perks for your time).
> >
> > David Enke
> > Pick-up the World
> > www.pick-uptheworld.com
> > 719-742-5303
> >
> >
>
> Do you happen to have an electronics simulation program? You might be able
> to enter this in fairly quickly and get some results. I have them
somewhere
> but not sure. It might be a cool idea. Personally I think any time
> something that has potential is cool. Ofcourse the outcome might not be
> what you thought be who knows... maybe better or maybe just need to be
> modified.
>
>
> Let me know if I'm off base on the idea.
>
> Jon

I don't have a program as you describe. I tend to simply dive into the
trenches, and then further refine the results if I need to. One of my
current projects that has been going on for many years is called the 'Hybrid
Polymag'. It's a great idea (in concept) that uses micro neodymium magnets
to sense string movements and transfer this energy directly into a piezo
type polymer film material. It is a magnetic pickup, but there are no coils
in it, and the prototypes come in about 1/8" tall and weight next to
nothing. The main variables have to do with the flux density of the magnets
combined with the mass to frequency ratio of the moving magnets, and then
this is mixed in along with the variable of the surface tension and size of
the polymer film. I can't imagine a program that could model the interaction
of all these things, so the result is that I'm perpetually tinkering with
them (argggggg, but not really!).

David Enke
Pick-up the World
www.pick-uptheworld.com
719-742-5303





.

Relevant Pages

  • Re: 6 "piece" PUs
    ... >> induce a current in the other... ... >> will induce a current with that frequency into the coil? ... >> both then add the signals together on the output. ... It's a great idea that uses micro neodymium magnets ...
    (rec.music.makers.builders)
  • Re: Please explain this about Humbuckers *VS* Single-coil PUs
    ... a vibrating soft-magnetic guitar string ... signal in the same direction as the other coil. ... When the signals from both ... Cause the magnets are reversed--North on one coil, ...
    (alt.guitar)
  • Re: 6 "piece" PUs
    ... > Hi Jon, Mattia, Clifford, all, ... > each string by employing a second coil winding as an electro-magnet? ... both then add the signals together on the output. ... This 'magnetic gain control' would consist of a simple ...
    (rec.music.makers.builders)
  • Re: Do spinning magnets lose angular momentum in space.
    ... noneferromagnetic coil in space. ... induce a current within the copperthread. ... interfer with the rotating magnets field? ...
    (sci.physics)
  • Re: Do spinning magnets lose angular momentum in space.
    ... torque is required to spin it. ... I meant that the rotor is easy to spin. ... were other magnets in your rig. ... The coil, on the other hand, is not free to> rotate. ...
    (sci.physics)