Zero Hum Strat Coil

[woody]

I just moded a Chinese Strat copy and it has been converted from something that sounded like a buss saw to a nice sounding unit. First I pulled it apart and glued a layer of Aluminium foil to the back of the pick guard and connected it to the small foil that the switch and pots connect to. I used conductive Silver glue to make the connection. I also star wired the Earth returns to the volume pot. The biggest improvement came when I sheilded the 3 single coil pick-ups, most people will say that if you try and sheild these that you lose the high end treble and the output drops and it sounds muddy. Ahh but there is a way to do it and it makes these coils nearly as quit as a humbucker. You need to get woven Copper conductive fabric and "partially" wrap the pick-up coil. I solder a small wire from the earth connection on the pick-up body and cut the fabric so that it wraps around 95% of the coil. I connect the small wire to the fabric with the Silver loaded glue and with contact adhesive wrap and stick the length of fabric to the coil winding. Make sure it does not make a full turn but only 95% of a turn (the start and finish should not touch or overlap) I do electronic design for a business and just put theory to the test and it works fine. If you wrap plain copper around a coil it acts like a shorted turn if it goes all the way around in a complete loop, this acts as a transformer and the shorted winding kills the coil output. The fabric I use has 70 threads per inch and this stops the formation of cross sectional Eddy currents that muddy the sound. The Currents cannot exist on the fine threads. If you want to try this and do not have a clue to what I am on about I will put up some pics if it is requested. Another trick when trying to eliminate hum is to work on the Guitar while its plugged into the amp, then as you try different grounds/sheilds or wiring layouts you can easilly hear if they make a difference.

Woody.

[humbuckr]

would love to see some pics. thanks

[woody]

These are some shielded coils that have been done with Copper foil and Conductive Silver paint. The Silver paint has a few ohms resistance and is applied right around the coil. I have also Silver painted the tops of the bobbins with Silver as to connect all the pole pieces together. I have also copper taped the magnet and used Silver paint for a conductive path onto the Earth Eyelet. This makes for a very quiet coil. I also did some copper fabric versions but they are in the Strat.

The pole pieces being floating from Earth conduct hum from the player via the strings by capacitive coupling, earthing them out helps kill the hum. The magnet is also couples hum into the pickup as it is not Earthed so either copper tape it or paint it.
All poles coil shield and magnet shield connect to the Earth eyelet via Silver paint.

[UnklMickey]

hi Woody,

let me give you a (belated) Welcome to GuitarNuts2.

you seem to have thought this out. carbon paint is much less expensive, but silver paint is more conductive and less prone to 'scuffing off', so that's probably a good choice here.

i think the "95%" plan makes good sense.

i wouldn't race to judge this as a 0% affect on tone, until some A / B comparisons were done on 2 identical coils, one of which was shielding.

But, i would guess this probably will have the most improvement in hum, with the least tonal affect, of any pickup shielding strategy i've seen thus far.


cheers,

unk

[woody]

Thanks for the welcome, It is a ongoing saga trying to make a single wound pickup hum and noise free without upsetting the tone.

Chris Kinman has a good article on tone on his site.
www.kinman.com/html/myStory.htm

I have a commercial bobbin winding machine that I can put to good use, If anyone wants to send me stuffed coils or empty bobbins I can professionaly rewind these and try overwinds with full shielding to see how they sound. I also have around 20 pounds of #42 wire. If you want to test new things then send me a PM. my thoughts are that if you cover the postage both ways I will do the winding and shielding for free.

I have a complete electronics lab so coil specifications can be Number of turns, resistance, inductance and even sheild to winding capacitance.


Here is a pic of my winder.

[jimijunior]

Hmm you seem like just the guy I need to get rid of my noise problem.

Tried shielding and star-grounding already but didnt do much for both my copy strat and CA strat.
So now I would like to shield the pickups on my copy strat first.

Would this be ok to try? (copied form steward mcdonalds site)

"Single coils
This is not recommended on vintage or rare pickups. This is a delicate job that may be better left up to a professional. This may also reduce some high end frequency from the pickup.

A great deal of the hum and buzz%ociated with single coil pickups can be eliminated by using this shielding kit as you will shield the coil as well as the output wire. The shielding of the output wire also allows you to switch the phase of the pickup (swap hot for ground) while still maintaining your shielding network.

Remove the pickups from the pickguard%embly and make note of which lug is hot and which is connected to ground. Be sure not to damage the two fine copper wires that exit the windings and are soldered to the wire lugs on the base of the bobbin. Carefully remove the pickup cover to expose the windings and/or protective tape. If the cover appears to be glued to the lower bobbin plate, stop and consult with an expert.

Wrap the coil with a strip of the black electrician's tape. Starting in the area of the two lugs on the lower bobbin plate and be sure to overlap the tape at least 1/2". Prepare to wrap the coil with the 1/4" copper foil tape by cutting a piece long enough to wrap once around the windings and overlap itself by 1/4". Remove all but 1/2" of the protective backing and start to wrap the foil around the bobbin. Start with the end of the foil that still has 1/2" of backing on it in the area of the solder lugs. Wrap the tape around the bobbin and overlap it over the part that still has the paper backing. From outside to inside in the area of the wire lugs you have the following layers: foil, foil, paper backing, black tape, black tape, windings. The paper is left in the area of the overlap because it reduces the risk of getting the area too hot when soldering and shorting out the windings. Before soldering you will want to check to be sure the cover can still be installed.

Cut a piece of the two conductor plus shield wire (included) the same length as the pickup's lead wires. Strip back 3/4" of the outer gray insulation on both ends and separate the outer braided shield from the brown and white wires. Twist the outer braid into a stranded wire and strip back 1/8" of the insulation off the brown and white wires. Carefully tin these wires. Using your VOM (Volt/Ohm Meter), check for shorts that may have occurred due to overheating one of the wires.

Very carefully desolder the two pickup lead wires from their lugs. Be sure that you made notes as to which lug was attached to ground and which was hot. Now solder the brown wire to the ground lug and the white wire to the hot lug. The outer braid is soldered to the copper foil where you overlapped the paper backing to protect the windings. It is also recommended to solder the point were the foil overlaps itself. This will insure that the foil will not loosen with age and makes for a better shield. To hook up the pickup: solder the white wire to the selector switch; the brown and outer braid to the back of the volume pot (unless you are using a phase switch). Check your shielding for continuity with your VOM and make sure that the hot wires are not shorted to ground. "

Along with copper taping the magnet and maybe pole section and connecting them to ground?

Man right now I wish you were my neighbour cause I'm about to give up on strats. You could probably even rewind my broken coil on my copy strat.

Thx for the info already provided m8!

[woody]

I myself have not tried the 2 wire shielded version but I may give it a go later on tonight and report back if there is much difference.
On my strat with 95% wound copper fabric tape and foil shielded magnet ant the Silver painted pole shorting technique my Strat is about twice as quiet as a mates Genuine 2005 Gibson with 2 buckers in it. Now I cannot detect with my fine tuned ear (Ha Ha) any difference in pitch/tone of the shielded pickup compared to a straight fender original. There is another way of getting a single coil strat sound and that is to use Dave Devers pickups. These may look like other dual coils but they are patented in his own name.

Dave has some pics of his pickups and some sound files on his site.
www.riffcraft.net

In the mean time I am going to buy a bucket of bobbins and wind some more designs for testing.

[jimijunior]

Hard to find the Silver paint.

Will this work?

www.bison.net/US/en/index.do (in search type "electro")

So far I have copper taped the bobbin and magnet (not grounded) but the difference is minimal so I need some silver paint to paint the pole area and make it all connect to ground. I heard a reduction in noise when connecting the magnet to earth. Soon I'll have a completely Copper guitar wearing a copper suit

[jimijunior]

Might as well ask you this too.

I read somewhere that there is a possibility to properly mod the string grounding wich would elminate the "touch strings to eliminate hum".
Do you know of such a mod?

Thx

[woody]

I grounded my Bridge with some Brass shim, I cut it to size and screwed the bridge plate down onto the shim and the metalic foil on the pick guard connects with the shim via a pressure contact. The paint I use is pure metallic Silver, not fake Silver paint. I use, www.semsupplies.com/Silver%20paint.html

[jimijunior]

But that get rid of the noise when you dont touch the strings right?

I read somewhere that you could avoid this and that would make my guitar alot more silent.
I dont undertstand why people find it normal to always have to touch the strings. I mean when you play open strings, what then?
Thx for all the info Woodie I'll look into it, need to get some silver paint first and do the pickups properly.

[jimijunior]

Woody, will this do?

www.bison.net/US/en/index.do (in search type "electro")

Cause I wont make an order with a shipment that costs more then the product itself

Thx

[woody]

Looks like it is the same stuff.
We just did a side by side guitar test with 2 squier strats. One had the pickups done and the other was stock standard. They sounded exacly the same except the shielded version had no noise. With this mod you can Single coil sound with humbucker quietness or better. I even wound up a mega hot coil with 20% more winds on it and it was just as quiet. A lot to be said for silver paint and the fine copper fabric.

[jimijunior]

Ok now I will defenetly try it on my new strat.

I canprobably manage to get a hold on that silver paint but for the foil will normal copper foil do for the pickups?
I shielded my copy and CA strats with that copper foil (adhesive of course) and still have some left.

Thx m8

[guitardoode]

Hey Woody!
Brilliant input and topic! +1
and i welcome you too! Sorry its rather belated but i dont really hit the forums as often as i used to.

Ive been experiment with my ole chinese strat and i have to admit ive been looking at modding the coils in that type of way but as people say it restricts tone. That copper fabric sounds genius and i'll have a look into it some time.

I dont know if anyone else noticed anything but i put a larger gauge wire for both ground and live and i noticed a slight brighter tone. but still i get this terrible buzz. and i still get this bizare "Microphone" feed back where even if i mute the strings i get the feedback.

[sumgai]

gd,

........ i still get this bizare "Microphone" feed back where even if i mute the strings i get the feedback.

I've got one word for you - Potting.

Check our Reference Articles Forum - Links topic, there's a section on this subject.

Good luck!


sumgai

[eljib]

doode:

it sounds like you should wax pot those things before worrying about any thing else. I mean, who needs brighter feedback?

EDIT:
Dang! I always get stumped by the single post on the next page. Looks like sumgai got to it first. Oh well, advice is better late (and repeated) than never.

[guitardoode]

ah Thanks Sumgai and eljib i'll be getting some wax to give that a shot now =-)
Funny enough though the feedback wasnt so much brighter. just louder.
-Guitardoode

[need2retire]

Hello Everyone ... new here.

Old topic, but I do have a couple of questions cause I couldn't find the answer in this post ... I may have missed something.

Woody's original post talked about using copper fabric (mesh) to do the shielding. The example pictures showed that a foil can be used as well. So the questions are:

1) Any difference using a copper mesh vs using a copper foil for pickup shielding with 95% wrap? I got an impression from Woody that the mesh would be better, but I was not able to grasp the concept 100%.
2) Can I shield the top side of the pickup (excluding the poles) as well? Or shield the sides only?

Thanks!!!

[stratatouille]

need2retire said:

Hello Everyone ... new here.

Old topic, but I do have a couple of questions cause I couldn't find the answer in this post ... I may have missed something.

Woody's original post talked about using copper fabric (mesh) to do the shielding. The example pictures showed that a foil can be used as well. So the questions are:

1) Any difference using a copper mesh vs using a copper foil for pickup shielding with 95% wrap? I got an impression from Woody that the mesh would be better, but I was not able to grasp the concept 100%.
2) Can I shield the top side of the pickup (excluding the poles) as well? Or shield the sides only?

Thanks!!!

Bonjour, M. Needs2retire!

I has similar questions about this same experimentation, and I hope my musings helps.

I noticed M. Ranchtooth and M. Ashcatlt helps a lot in other thread, and I explored through some of what they says in the past. I found M. Ashcatlt has some words here that may be explaining what M. Woody is also explaining? I do not know - look.

Http://guitarnuts2.proboards45.com/index.cgi?action=display&board=wiring&thread=1174583569&page=2

Reply #24 on Mar 28, 2007, 9:46pm

"I also think I've figured out the answer to my other question so for no good reason I'll try to flesh it out using a reference from my trucking days.

If you want to go from chattanooga to atlanta and back (without stopping in atlanta), you could take I-75S till you reach the I285 loop, then go around the loop and back onto I-75N. The treble and noise would like to get from atlanta to chattanooga, so they get on the I285 loop, but they keep missing the exit for I75, and keep going around the loop...

that makes sense to me anyway."

I may drink a lot of wine, and is why this is maybe making sense to me also.

M. Ashcatlt is talking about something or the other, but also is making sense of what M. Woody is fixed, but maybe in reverse order of logic.

The wires is preventing currants in Atlanta, so they do not steal treble and choo-choo to chattanooga and lose it there, is why the mesh is working the best. Also, mesh must be in pair with other rule of "95%" (i.e. do not let the one end of the whole assembly come to contact with other end of the assembly).

Solid copper foil allows currants, and the currants hi-jack treble and choo-choo to chattanooga with it and loses it, which is affects tone. Do what M. Woody says, because of what M. Ashcatlt says - sort of.

I think is probably okay to wrap the top - but I wouldn't touch the poles (I bet is okay to touch the poles, but why take a chance of unwanted choo-choo to chattanooga, yes?).

I would drink wine before attempting any experimentations, but is just me. Okay.

M. Strat

[azrael]

I haven't read everything in this thread, but I just wanted to contribute that I have two single coils in my Strat that are shielded, and they have very little hum. I don't think it dulls the tone or makes them sound muddy, but they are a tiny bit darker. I don't mind it at all.

[stratatouille]

M. Azrael wrotes "I have two single coils in my Strat that are shielded, and they have very little hum. I don't think it dulls the tone or makes them sound muddy"

M. Azreal also wrotes "but they are a tiny bit darker."

Well, which is it M. Azreal? Tiny bit darker, or don't think it dulls the tone?

Tiny bit darker is a bit of treble being lost, no? This is all that was being implies, and if you are okay with that, how you say "okee-dokee then".

"I don't mind it at all" is a statement of your personal preference.

Is fair statement, but still does affect tone, as implies. Yes?

Good to know you did this with satisfactory result. Great job.

Okay.

M. Strat

[azrael]

Well, I don't think "tiny bit darker" qualifies as dulls the tone. Dulls the tone is quite a extreme statement, IMO. I would reserve that for something like a noise gate that colors your tone in a bad way.

In any case, the "darker" aspect isn't anything negative, IMO, as it's a very small change in tone, for a huge difference in hum reduction.

[ssstonelover]

Where can I buy, or order, woven Copper conductive fabric, 70 threads per inch?

Thanks,Bill

[jkemmery]

FWIW, I've had very good luck with shielding not only the pickguard, but the entire pickup cavity, which seems to eliminate all but a barely perceptible amount of hum without effecting tone whatsoever. I prefer that solution than messing around with trying to shield the pups and lose some tone, but that's just me. Since I prefer slightly overwound single coils, I like to keep as much treble as possible. I also like to use 500K pots, but that's another topic entirely, no?

BTW, Stratatouille, you crack me up something fierce.

[ChrisK]

Well, it helps block the rays from the secretive aliens on Mars, but it doesn't stop the voices in my head (!Obey!).

Shielded bed sheets

They have other stuff as well.

I searched for "woven Copper conductive" all these words.
I use AltaVista, this was the first of many links.

[stratatouille]

M. Jkemmery wrote "BTW, Stratatouille, you crack me up something fierce."

Thanks you so much for that. I am happy I could be of assistance to you, and - more more important, I am HATE trying to learn ins and outs of how English goes.

Now that I know I am good enough at it that you get what is I am saying, and we get bonus of amusing with my miscellaneous ramblings, as they say - fuhgettingaboudit! Okay.

M. Strat

[newey]

OK, I'm new at this shielding stuff so this may be a stupid question. If so, please be tolerant. I'm building a single humbucker strat (a la Tom DeLonge Strat) so noise may not be as much of a problem to begin with, but I want to be as stealthy as possible. There is a large expanse of pickguard with no electronics neaby since there's only the single P/U. There's also a large expanse of "bathtub routed" cavity up to the neck w/o anything in it. Should I shield the entire pickguard and cavity, or can I get away with just doing the areas right aroung the pickup? Also, since I have plenty of room in the cavity, rather than the "star grounding" technique I was going to put in a grounding buss using spade connectors and terminal block. Is this equivalent to the star grounding or will it create noise issues of its own?

[ereseminole]

could you please post some more pics of some of your copper threads, ive never seen such thing....wer can i get this stuf??

[johnnygtar]

Woody, you genius! Where have you gone off to? Come back!