Dummy Coil Experiment - Successful!

[reTrEaD]

This would be the result:

1 - Neck in series with Dummy
2 - [Neck in parallel with Middle] in series with Dummy
3 - Middle in series with Dummy
4 - [Middle in series with Dummy] in parallel with one coil of Bridge
5 - Bridge (full HB)

Because of the "bridging" of contacts in the #2 and #4 positions, using the switch this way doesn't gain you anything over just wiring the (-) of the Neck and Middle together to the (+) of the Dummy. Plus you create a minor hanging from hot issue (dummy) in the #5 position. Not the end of the world, but when you can avoid it, you should.


OOOPS!
I missed something.
In the #3 position, you get [Middle in series with Dummy]in parallel with one coil of the Bridge pickup.
In the #2 position, you get {[Neck in parallel with Middle] in series with Dummy} in parallel with one coil of the Bridge pickup.
Yikes!

[newey]

ReTrEaD said:

This would be the result:

1 - Neck in series with Dummy
2 - [Neck in parallel with Middle] in series with Dummy
3 - Middle in series with Dummy
4 - [Middle in series with Dummy] in parallel with one coil of Bridge
5 - Bridge (full HB)

My understanding of what RG wanted was exactly this- dummy coil on the neck and middle, not on the bridge. I guess the assumption here is that the neck and mid pickups will both be the same, not with one RWRP.

OOOPS!
I missed something.
In the #3 position, you get [Middle in series with Dummy]in parallel with one coil of the Bridge pickup.
In the #2 position, you get {[Neck in parallel with Middle] in series with Dummy} in parallel with one coil of the Bridge pickup.
Yikes!

Double OOPs, I missed it, too. But this can still work:

Because of the "bridging" of contacts in the #2 and #4 positions, using the switch this way doesn't gain you anything over just wiring the (-) of the Neck and Middle together to the (+) of the Dummy.

So, if RG does that, putting the dummy on the negative end of the neck and middle, then the dummy is completely removed from the switch. So, now the switch can be wired as per std. HSS practice to get the split coil at position #4. Right?

[reTrEaD]

Right. That's one possibility. The other would be to use the second side of the switch to shunt the dummy in the #2 and #4 position and not split the HB.

[JohnH]

How about this? (or is this what we are talking about anyway?)The arrows indicate hum direction:


It should be hum cancelling in all positions. There's no hanging from hot, and dummy is shorted out in position 4 where its not needed.. The arrows indicate nominal humdirection.

ps - anyone noticed Photobucket down today?

[reTrEaD]

I like it a lot, John. What Newey and I were hashing out requires the Neck and Middle pickups being of like magnetic polarity. What you have only requires adding a dummy coil.

[newey]

Yes, an elegant solution, and definitely better than what I was envisioning. But are we not splitting the HB?

[rabidgerry]

My understanding of what RG wanted was exactly this- dummy coil on the neck and middle, not on the bridge. I guess the assumption here is that the neck and mid pickups will both be the same, not with one RWRP.

This is correct. Just dummy coil on neck and middle because I don't need it on a humbucker. I haven't split the humbucker but I will at some stage I'm sure.

But I'd like to concentrate solely on having the dummy on the neck and middle only. I guess this would include the in between position of neck and middle. I hadn't even thought about pos 4 which will be single in paralell with the bridge.

[reTrEaD]

Dec 8, 2015 9:18:50 GMT -5 rabidgerry said:

But I'd like to concentrate solely on having the dummy on the neck and middle only. I guess this would include the in between position of neck and middle.

Gerry, the way to proceed starts with the magnetic polarity of the Neck and Middle pickups. On most modern Strats and Strat clones the Neck and Middle have opposite magnetic polarity. This is easy to check with a compass or small magnet. If one end of the needle or magnet is attracted by one pickup and repelled by the other, they're of opposite polarity. In that case, John's suggestion would be best.

If they're of the same magnetic polarity, please let us know.

[rabidgerry]

sorry that was silly of me to leave out, yeah the middle is rwrp meant to say before, no need for compasses when I already know

[JohnH]

With an rwrp middle, then that should work with the diagram that I sketched.

Newey mentioned coil splitting. Some HSS wirings automatically split the humbucker in position 2. My sketch doesnt do that but gives you a hum cancelling mix of the bridge humbucker plus M with dummy.

I cant see how to do auto-split here and also keep everything hum-free. But I do have a doodle of how to adapt my sketch to use a push/pull or mini-toggle to split the humbucker and use one of its coils with the dummy coil for a noise-cancelled bridge single and in position 2, hum-cancelling Bsingle plus M without dummy. That would give two extra clear bright sounds but still all modes hum-cancelled.

BTW in all these cases, unless coils are perfectly matched, humcancelling is useful but not perfect. Also any dummy coil will somewhat darken tones which its why its best to cut out the dummy when opposite pickup coils can do their own noise cancelling.

[rabidgerry]

Ahh nice one John.

Will you be disappointed if I told you I can't understand schematics so well? Don't laugh.

Still waiting on the pickup arriving, busy since it's Christmas and all that!

[reTrEaD]

Dec 9, 2015 4:47:24 GMT -5 rabidgerry said:

Don't laugh.

I won't laugh. And I doubt John will. Schematics rather than wiring diagrams are great for those of us who are familiar with them but can be very difficult for those who aren't familiar.

Maybe we can enlist someone's help in converting that to a wiring diagram for you. But there are a few variations of 5-way switches. CRL and Oak-Grigsby have their lugs in the same pattern. They're used on Fender and some other brands of Strat clones. Stew-Mac replacements have a slightly different pattern, basically a mirror image. Some import switches have all 6 lugs in a line. So does the Megaswitch-S, but the lugs are in a different sequence.



Can you tell us anything about your switch or what brand of guitar you have?

[rabidgerry]

Dec 6, 2015 3:59:41 GMT -5 rabidgerry said:

Yes I normally perform that mod. Actually now I think about it the strat I am thinking of doing this with only uses one master tone pot (its a sort of rare KV98 squire made for the southern American Market).

That's useful showing the different types of switches though. I have a few Korean models like this one I'm trying the mod on that have the poles all down one side.

I might replace it with a heavier duty switch, I dunno.  I'll check later and make sure it's in good order.  If it is I'll stick with it.

PS the pickup arrived!!

[reTrEaD]

Hello Gerry,

Squier's diagram might be a good starting point. It isn't laid out exactly the same way the parts are on the pickguard but the parts have the same look as they do in real life.

Stock, before modification:



Assuming you won't be replacing the switch, would you be able to follow the stock diagram well enough that modifying it would be useful?

[rabidgerry]

Oh yes certainly, I just can't read schematics (well just a tiny bit).

I've much experience in modding. A lot of which I learnt from this site. I did a 26 sound strat setup one time using everyones help and know how from this site. The diagram is still on here somewhere.

But yes I could follow a modded diagram of the like you posted with no issues.

Thanks for the help BTW.

The tele pickup cover was a nightmare to get off, it was glued on!! I got it off without damaging it though. Reads slightly more resistance without the cover on! About 5.8k

[reTrEaD]

Okay Gerry, here we go . . .

The diagram got sorta busy after all the changes were made so I included a copy of the original at the bottom for reference.  The colored arrows on the original point to the four wires that will be moved and one jumper that will be cut.  The wires from the dummy and an added wire are in color.  I drew the dummy coil to look like a strat pickup.  The polarity is correct if the dummy is a strat neck pickup and it's face up the same as the actual pickups.   You would need to exchange the white and black if the dummy is face down.

I don't know how the winding direction and color codes of your lipstick relate to a strat neck pickup.  Seems like it would be easy enough to flip it over if you get the polarity wrong.

Wait until someone else vets this, in case I made and error.


Cheers!

[newey]

RT-

Your diagram looks fine as per John's schematic.

[rabidgerry]

Dec 15, 2015 1:00:37 GMT -5 reTrEaD said:

Okay Gerry, here we go . . .

The diagram got sorta busy after all the changes were made so I included a copy of the original at the bottom for reference.  The colored arrows on the original point to the four wires that will be moved and one jumper that will be cut.  The wires from the dummy and an added wire are in color.  I drew the dummy coil to look like a strat pickup.  The polarity is correct if the dummy is a strat neck pickup and it's face up the same as the actual pickups.   You would need to exchange the white and black if the dummy is face down.

I don't know how the winding direction and color codes of your lipstick relate to a strat neck pickup.  Seems like it would be easy enough to flip it over if you get the polarity wrong.

Wait until someone else vets this, in case I made and error.


Cheers!

He reTread, thanks for doing that up, I appreciate it. One thing I have to say is, my Strat only has one single Master Tone control. A rare configuration for that type of guitar I know, but it was a randomly short lived model of Squier strat.

I don't need the diagram modded though I can work with what you have posted.

Ok I might get started on this over the weekend! I've pickups to test in the same axe and a different trem to install also so not sure where to begin to be honest. Might just do the dummy coil and do the rest after as I love doing tests with a guitar before I make any changes just to see the comparison.

[rabidgerry]

Ok ready to mod.

I have amended the wiring diagram

can anyone tell me if I have done it correctly?

I basically got rid of a tone pot and used the single remaining tone pot as the master tone pot for all the pickups. Please check this out guys and see if it makes sense.

[reTrEaD]

Gerry, bridging all the contact together on the left side of the switch created a big problem. Your tone control became a master but among other things, your bridge pickup will always be selected. Obviously not good. This would be a better course of action:

[rabidgerry]

Thanks reTrEaD

ok man no sweat I'll give this a go and let you know how I get on.





R.I.P Lemmy from Motorhead

[rabidgerry]

ok followed the wiring to a T and I can't put the scratchplate back on now. There doesn't appear to be enough room.

I plugged the guitar in anyways to see if I could hear any difference. It sounded a tiny bit quieter, but still made noise. But a different sounding noise.

I have shielded my guitar before this mod so I'm wondering is it perhaps the fact the dummy coil is sitting uninsulated and touching the shielding?

Also the pickup I am using only has two wires. One is the signal wire and the other is literally just an un insulated earth.

Any suggestions on how to improve things? I would not say this dummy coil has worked at all really?

[newey]

Gunther's original post talks about his experimentation in positioning the dummy coil within the cavity to get the best hum cancellation, so that may be an issue.

Is the two-wire pickup the one you're using as the dummy, or one of your pickups? If it's the dummy coil, I wouldn't think that should matter noise-wise, since the dummy isn't sensing the guitar signal anyway. You definitely should try insulating it from the shielding, though- a wrap of electrical tape should do the trick.

[rabidgerry]

Dec 30, 2015 7:02:07 GMT -5 newey said:

Gunther's original post talks about his experimentation in positioning the dummy coil within the cavity to get the best hum cancellation, so that may be an issue.

Is the two-wire pickup the one you're using as the dummy, or one of your pickups? If it's the dummy coil, I wouldn't think that should matter noise-wise, since the dummy isn't sensing the guitar signal anyway. You definitely should try insulating it from the shielding, though- a wrap of electrical tape should do the trick.

Yeah man the two wire pickup is the dummy coil.

Also, and this might sound stupid, but do I need to remove the pole pieces? I removed the magnet on the bottom but I didn't take out the poles because I did not think they needed to come out.

[sumgai]

'gerry,


There's a gotcha in your question about pole pieces... In essence, those are some form of steel, and therefore the do have some magnetic properties.  The additional magnet (on the bottom?) just added more strength to the magnetic field, and the pole pieces focused all that strength to a narrow area under the strings.  In essence, if the pole pieces are actually near the strings, then they might be sensing enough string vibration to be contributing to the tone - emphasis is on the word "might".

For that reason alone, a coil without pole pieces is usually considered a good thing.  However.... taking a standard guitar pickup and attempting to remove its pole pieces is most often a crap-shoot.  You can expect that there's probably some kind of adhesive holding the pole pieces into the bobbins, both upper and lower, and that driving the pieces out in almost any fashion will wreak havoc on those bobbins. (Cracks, or worse, total breakage.) In addition, most pickups are wound around the pole pieces themselves (no intermediate form, not even tape*), thus if you disturb the pieces in any direction, you risk breaking some (several!) windings within the center of the coil.  That right there says "Don't Do It".

If you must go down this road (and what the hey, you're Nutz like the rest of us!), then experiment on cheap pickups first, saving your experience for a known and desired quality pickup.  In fact though, you may find that a successful 'extraction' from a cheap pup might still work in your intended dummy position, who knows?

HTH




sumgai


* The wire used in a pup is insulated with a thin coat of varnish, which is enough protection against any shorting via contact with the steel pieces.

[rabidgerry]

Dec 31, 2015 12:34:18 GMT -5 sumgai said:

'gerry,


There's a gotcha in your question about pole pieces... In essence, those are some form of steel, and therefore the do have some magnetic properties.  The additional magnet (on the bottom?) just added more strength to the magnetic field, and the pole pieces focused all that strength to a narrow area under the strings.  In essence, if the pole pieces are actually near the strings, then they might be sensing enough string vibration to be contributing to the tone - emphasis is on the word "might".

For that reason alone, a coil without pole pieces is usually considered a good thing.  However.... taking a standard guitar pickup and attempting to remove its pole pieces is most often a crap-shoot.  You can expect that there's probably some kind of adhesive holding the pole pieces into the bobbins, both upper and lower, and that driving the pieces out in almost any fashion will wreak havoc on those bobbins. (Cracks, or worse, total breakage.) In addition, most pickups are wound around the pole pieces themselves (no intermediate form, not even tape*), thus if you disturb the pieces in any direction, you risk breaking some (several!) windings within the center of the coil.  That right there says "Don't Do It".

If you must go down this road (and what the hey, you're Nutz like the rest of us!), then experiment on cheap pickups first, saving your experience for a known and desired quality pickup.  In fact though, you may find that a successful 'extraction' from a cheap pup might still work in your intended dummy position, who knows?

HTH




sumgai


* The wire used in a pup is insulated with a thin coat of varnish, which is enough protection against any shorting via contact with the steel pieces.

Thanks SG

well I read a litte more about and watched a video of some guy making a dummy coil and they both keep the pole pieces and say that it's actually better for noise reduction, so I shall keep my poles in. How can I get this dam thing to work though? I haven't looked at it since last week as I'm pi$$ed off at it :)I need to insulate it from the shielding first, this is the only thing I can think of trying.

[JohnH]

A few thoughts:

One thing about dummy coils in series is that in order to get a good reduction in hum, they need to be carefully matched to the other coils, in terms of the amount of hum they collect. If your dummy coil is making more anti-hum than needed, a resistor across it may help, starting with testing with a 250k or 100k pot connected with two wires to shunt it, and sweeping it to see if there is a null at a certain setting.

or, in one of the switch settings, if you short out either the main coil or the dummy coil so you only get hum from one, can you tell if one is louder than the other?

Another obvious check, is that the dummy coil needs the axis of its pole pieces in the same direction as the other pickups.

As to whether the dummy should have its pole pieces in place, Id say ideally not, in order to reduce its inductance and have less effect on tone. But in terms of whether this will be better or worse for hum, it cant be said without testing. I would expect that with its poles, the flux lines of hum would be more directed through it and it would attract more anti hum.

In experiments, I've never been able to get much of a conclusive result on the couple of occasions when I have messed with dummy coils. I have never committed to properly building them right into a shielded guitar, and I find bench-top tests tend to pick up so much spurious hum that this dominated the results.

[sumgai]

'gerry,


I'm with John here.  The reason to remove the pole pieces is to reduce the focusing of the magnetic field, such that it no longer influences the environment, i.e. the string vibrations.  Most dummy coils are installed in a way that they line up with the normal pickups, thus they could easily affect the overall tonality, if the pole pieces are left intact.

Reducing the overall inductance is most often a benefit, if for no other reason than to reduce the muddiness of any resulting combination.  But if leaving the pole pieces in actually helps the hum reduction, then I'd say that John's surmisal about matching coils is proved yet again. IOW, said pickup/dummy coil was made so poorly that it needed all the help it could get.  

Well, either that, or it was installed in such a way that it was mis-aligned with the other pups.  And we can only guess at what that did to our desired results.

HTH




sumgai

[rabidgerry]

forgive me SG but some of that went over my head.

So are you saying remove them or don't remove them?

I personally think the wiring is wrong.

So far since original install I have swapped the wires since the last time (the signal and ground wires of the pickup). No real change, the single coils are noiser than without the dummy coil, impossible to use. I also insulated the dummy coil. Did nothing.

I also cannot fit the dummy coil in the cavity. My strat must be more shallow than others. My solution to this, try fit it perhaps in the trem cavity? Good idea - bad idea?

Another question, since I cannot close the guitar up as I cannot fit the dummy inside, will this affect anything? To test I made sure the shielding on the pick guard touches the shielding of the body to still create the faraday cage. To make sure it's right I flick the switch on to the humbucker and it works as normal so I figured so should the singles.

check the pics out



I could not hold the camera still!! But you can see what I have done here




edit: just I started to put stuff away I actually fit the coil in better!!! I put it on it's side and hey presto! I could at least get most of the guard flat enough. I'm sure with a little more wire arranging I could make it a little better as well. I could screw it down the way it is now but I don't want to strain any wires.

[rabidgerry]

Ok as a test, could I just hook up the dummy coil to one pickup (the neck)?

Just to see if it works in a more standard wiring setup.

Would I just attached the pickups positive to the positive of the dummy and then wire the negative to the tab on the selector switch?