Rewinding cheap Tele neck PU

[bea]

@Dave - no problem, i just wanted to avoid misunderstandings.

@rjb: i think the resonance peak was still quite audible, and the "boomy" range was much below the frequencies of the assumed resonance (in the past i have done a lot with additional capacitors and even done simple PU modifications like adding steel bars to the central poles of epiphe mudbuckers). I even ran the guitar through the Hi Z input of my mixer and listen to it through headphones which made this pretty audible.

The pickup has been bought with the plan to rewind it, and to rewind it with low impedance in order to experiment with that - it was simply a lot cheaper than any other source of the parts. If my aim had been to be sure that the PU was well sounding i would have spent a bit more for a GFS, Wilkinson, Viva or the like.

Anyway, the guitar is put into pieces again (it is a prototype stringed up the first time); it still needs a lot of work to be done. I bought the tele PU because i liked the look of such a small pickup. It is not in neck position but at 10% scale length similar to music man stingrays. Despite of the sound of that specific pickup the flexibility of the sound seems to be pretty poor - compared to the possibilities of the typical neck position. I will have to completly rethink the concept, maybe use a humbucker instead.

best

Beate

[rjb]

...I even ran the guitar through the Hi Z input of my mixer and listen to it through headphones which made this pretty audible.

Just for future reference, that may not be a "fair" test.
What is the input impedance of the Hi Z input of your mixer?
The "Hi" Z inputs on my old EV mixer are 50K ohm (pretty typical for pro sound boards);
normal passive guitar pickups like to see >= 1M ohm.
Most passive hi z pickups sound horrible if plugged directly into a mixer; they need to be buffered with a preamp or stompbox or something.

Anyways, if you ever do mod the tele p'up, I think the boominess will go away with the low Z winding.

[bea]

First of all, i have also run it through my guitar amp which has an input impedance of 1 MOHm. Secondly, one input of my mixer is switchable between something around 50 kOhms and a large impedance suitable for the guitar - i use that input regularly for my practising on the bass.

[Steve A.]

Bea:

I was just thinking that since you are building this guitar do you have to stick with the traditional tele neck pickup dimensions? I think that you might have better luck winding a low impedance coil on a strat-sized pickup- or perhaps a P-90.

BTW you might want to check out the Craig Anderton varitone emulation circuit that uses a Mouser 42TM-019 audio transformer as the coil. It is Project No. 3 "Passive Tone Control" in the 1980 edition of "Electronic Projects for Musician." Although he shows it as a stand-alone box it can also be wired into the guitar if there is room. With a push-pull pot you can switch between a regular tone control and the PTC in a tele.

I think that "Garbage In Garbage Out" might apply here- if you start off with a crappy sounding pickup custom filters are probably not going to get a good authentic sound from it...

I'm sure Bea can answer for herself, but I'm not sure she wants an "authentic" sound.
It seems she wants to wind a low impedance pickup because she wants to wind a low impedance pickup.
Not that there's anything wrong with that.

I was responding to the suggestion that Bea try to filter the signal from the existing pickup (with "authentic" meaning the opposite of a machine-like artificial sounding tone.)

Perhaps I overlooked some of the posts here but I got the impression that trying to rewind the existing pickup would be a lesson in futility- it was suggested that she build the pickup from scratch using alnico slugs and fiberboard flatwork which sounds like a good idea to me. Low impedance, high impedance- whatever she wants.

If Bea's tele has a typical control cavity there is not a lot of room in there. One trick to make it larger is to undercut the opening so the control plate will still cover the cavity but there would be room underneath to put circuitry and maybe even a battery there. (I had to undercut the cavity in one of my teles to fit a 4 pole 5 position selector switch- it would have worked better had I not already shielded the cavity with copper foil tape. )

Peace out

Steve Ahola

[rjb]

...one input of my mixer is switchable between something around 50 kOhms and a large impedance suitable for the guitar - i use that input regularly for my practising on the bass.

Kewel. That is a nice feature.

Here's what I was trying to get at:
Many mixers designed for live sound enforcement have XLR mic inputs and 1/4" line inputs.
Some manufacturers refer to the 1/4" inputs as "high impedance" inputs, without specifying the impedance value.
Those inputs typically are "high-impedance" compared to a low-impedance mic input- but not high enough to satisfy a guitar.
Not everyone realizes that, and I do know of people who have tried plugging guitars directly into such boards.
Since you didn't specify what mixer you use, I thought it wouldn't hurt to ask its input impedance.
I didn't mean to question your competence or common sense, and I hope this clears up any misunderstanding.

Peace, Love and Understanding,
Ralph "Socially Inept" Barthine

[David Schwab]

I have a Roland digital mixer that I use for recording. It has a hi-Z guitar input that works very well.

For a low Z pickup it doesn't matter, and you can plug most directly into a mixer and then use the mic preamps to crank up the level.

[Joe Gwinn]

Bea,

Where do you hail from? Please update your Profile with city and country.

Thanks

[Joe Gwinn]

Bea,

Where do you hail from? Please update your Profile with city and country.

Thanks

[bea]

Ok, here is the result

My improvisational winding setup. Fully sufficent at least for thick wire. I used 0.2 mm. Scatterwound is guaranteed.



Waxing:



The result:



480 windings of 0.2 mm wire, DC resistance about 37 Ohms, resonance at 1 nF load about 50 kHz.

Now, still without additional circuitry to form the tone, it sounds very "open", almost acoustic (into the PA). To my surprise really useful.

I will redo the resonance measurement using Lissajous figures. And then experiment with lowering the resonance and the damping. After that i will decide on the preamp, notably with or without tone control in addition of switchable resonance.

[bbsailor]

Ok, here is the result

My improvisational winding setup. Fully sufficent at least for thick wire. I used 0.2 mm. Scatterwound is guaranteed.

[ATTACH=CONFIG]21565[/ATTACH]

Waxing:

[ATTACH=CONFIG]21567[/ATTACH]

The result:

[ATTACH=CONFIG]21566[/ATTACH]

480 windings of 0.2 mm wire, DC resistance about 37 Ohms, resonance at 1 nF load about 50 kHz.

Now, still without additional circuitry to form the tone, it sounds very "open", almost acoustic (into the PA). To my surprise really useful.

I will redo the resonance measurement using Lissajous figures. And then experiment with lowering the resonance and the damping. After that i will decide on the preamp, notably with or without tone control in addition of switchable resonance.

Bea,

Try feeding this pickup into a microphone matchine transformer like a Shure A95U plugged directly into the guitar amp. Then use a stereo output jack in the guitar to send the signal with two conductor shielded wire to the XLR connector that plugs directly into the A95U. This will boost the output by approximately the turns ratio of the A95U transformer or 1 to 12. You should hear a very bright sound with less guitar pickup resonance in the traditional 3 KHz to 5 KHz range. The noise should be lower also.

For your next experiment try using served Litz wire of 40 strands of awg 44 (OD .018") which equals AWG 28 in resistance.

Welcome to the world of low impedance guitar pickups.

Joseph Rogowski

[bea]

Ok, some further experiments: resonance with a load of 1 nF 44.5 kHz. Damping resistors of the order of 2 kOhms will be possibly appropriate - the ears must decide. Useful load capacitances will be somewhere between 100 nF and 1500 nF, checked on the scope. I do not want to use many settings in that guitar, just the PU as is, something around 3 kHz and something low to obtain a smooth, jazzy tone.

[Mark Hammer]

I gather that the wire leads from the pickup are one of those cables that would normally connect the audio output of a CD drive to the sound card? The black shrink tubing gves it away.

I bought a bunch of those for myself for the exact same purpose. I hope this falls under the heading of "great minds think alike" rather than "fools seldom differ"!

[bea]

Yes, Mark, You are right. BTW, i did not need o buy these chords - CD drives are not very long lived. Each dead one gives You a new chord...