Suhr Backplate Silent Single Coil

Pickups, wiring schemes, switch techniques and onboard active electronics for guitars and basses
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atreidesheir
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Post by atreidesheir »

I have not given up on this project. Life is just getting in the way.

A little research has suggested to me that the dummy coil can be wound with insulated wire (at least it is acceptable in antenna coils). I have some 8-strand insulated wire and will make my coil from that after I get a good estimate of the gauge/weight of the copper in those wires in there so I can calculate the windings. Then I will wire it with the two pots and see what happens. I may try my copper foil antenna idea on a second guitar I will try to quiet. I just need to compare the mass of the copper foil to the copper wire. I should be able to locate a spec sheet for the wire and perhaps the foil also.

Stay tuned.
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Post by DaveKerr »

Late to this thread, but I'm pretty certain that the gauge of the wire doesn't matter an awful lot in terms of signal strength - the critical factors are number of turns and area per turn.
Here's another thread on dummy coils from the same forum above http://music-electronics-forum.com/t124/#post4301
... multiple LFO waveforms (saw up, saw down, triangle, square); a more flexible envelope with attack/release controls as well as inverted envelope. I am afraid it will have more knobs than the TGP annual convention - frequencycentral

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Post by atreidesheir »

I apologize for my long absence from the forum and this thread in particular. I have abandoned this project. I did achieve the desired effect using 200 turns of copper wire and two pots for resistance. I did not like the result and have decided to stick with single coils in all their traditional hum. I did not like the affect on my tone and the guitar.

It made the tone sound plasticky. Like a lace sensor. Not terrible, but a definite step down from the more organic tone of my Seymour Duncan Antiquities. Dynamics were quite reduced.
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Post by jwmallett »

I have a couple of questions. First, I notice the schematic only shows one pickup, this seems unfinished to me, how would hooking all the pickups through the same lead through both pots allow adjustment of each pickup? Can someone clarify how the pickups know which pot is intended for them or what I am missing. This is for educational purposes of course.

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Alex Frias
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Post by Alex Frias »

I'm starting to test a dummy coil on the backplate in a Vintage Reissued Series V6. If I get any kind of success I will post it here.

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ianmusic
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Post by ianmusic »

how to diy this system???

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Post by DrNomis »

I've been having mains hum issues with my Mexican fender standard strat guitar and have been able to determine that my stock single-coil pickups are picking-up the magnetic fields of the mains wiring in my flat, shifting the orientation of my guitar varies the hum loudness, also the pickups are picking-up the refresh rate of my PC's monitor too, I've been seriously thinking of replacing the stock pickups with a set of Fender Vintage Noiseless ones.... :thumbsup

Might even give this silent back-plate idea a go too.... :thumbsup
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Post by phatt »

Hey DrNomis,
Indeed it's magnetic induced hum not radio interference which means use Steel not copper.
If it has the full swimming pool route cavity for PU's then a jam or coffe tin is ideal.
Cut to size and double sided tape it to the cavity. Don't forget to solder an earth wire to it.

Certainly worked wonders for my cheap strat copy. :thumbsup
My guess is the back plate trick is still not perfect and it's a lot of money or messing about if you try to build one and a jam tin is likely just as good.
Phil.

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Post by bassetrox »

Hi there guys, I'm putting a simple tutorial together on how to DIY one of these things as I attempt the project myself. If you're interested, or if you guys who've done it can give me any valuable input, take a look at http://www.ampworks.co.uk/experiments

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Post by phatt »

My thoughts on this will not bode well if you are the guitar player that just insists on,,
More of everything that even smells like GAIN has to be much better than less. :popcorn:

The back plate as like the Kinman PU ideas are valid but if you have 45 fuzz boxxes all maxed out into a hi gain valve rig with a wine rack of holy smoked glass in the back then there is little hope of noise reduction. winky.
There are limits to what can be done. Hint!
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Post by Jarno »

Interesting experiment, I think Rick Turner also mentioned that you can get rid of quite a bit of hum by using a dummy coil, which doesn't need to be exactly the same shape or number of windings as the pickups (or thickness of wire used). He was talking about the humcancelling system that Alembic uses (which he helped to design). In an Alembic there's the middle "pickup" which is actually a dummy coil, Rick's idea was to just put a coil in the control compartment.
These are active systems however, and I think that would make it a lot easier to tune the coil to deliver exactly the right amount of anti-hum signal, but maybe that'll change your sound too much (although it is perhaps preferrable to find a way around this, and have a guitar which is bomb-proof in EMI-rich environments, than have something which is passive but doesn't work all the time).

Edit:
If you are using an active system, adding a mixer stage for the center pickup is easy too. One two-input mixing stage per pickup (pickup + dummy coil), so that's three opamp stages, perhaps use one opamp for a precision voltage reference, you'll get by with using a single quad opamp package, not too bad.
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Post by Cub »

Bump with some relevant photographs. 8)

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Post by apollomusicservice »

Any info about coil: No turns, inductance, wire diameter...? :?:

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Post by biliousfrog »

I've just installed a dummy coil in my Tele - does the same thing, takes moments to install, has been used for decades by people such as SRV.

As with the Suhr/Ilitch coil, it doesn't work with reverse polarity pickup selections so I've just fitted mine to the bridge pickup - I am considering another for the neck but I rarely use it for dirty sounds where the hum is most apparent. The bridge sound is now quieter than the middle position, almost silent.

All you have to do it take a regular singlecoil pickup or half a humbucker, remove the magnet(s) and pole pieces and wire it in series with the offending pickup(s). In a Tele/Strat you can mount it under the controls....simples.

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Post by biliousfrog »

Slow day today so I just put another coil in the Tele for the neck pickup - I found a set of really old pickups, no idea what they were, but managed to take the windings off the bobbins and squeeze it into the wiring route under the pick guard.

The result - near silent Tele in all positions. There's a very slight treble loss but negligible and it simply means that I've turned up the tone pot rather than having it always at half (using 500k pot anyway). I've got a Lace Sensor loaded strat and I'd say that the hum levels are the same...in fact my other guitars are now sounding quite bad :?

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Post by youdirtyrat »

how did you connect it ... do you have time to make diagrams?

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Post by biliousfrog »

http://frettech.com/dummy/

Wire one end of the coil to the pickups "hot" switch connection, wire the other end to ground. You'll need to test each wire first, it will be obvious which way round they need wiring as one will cut hum and the other way will do nothing. If your pickups are both the same polarity then you could wire the coil to the work with both pickups, otherwise you'll need two coils.

Searching Google for "dummy coil" will bring up a lot of info

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Post by youdirtyrat »

thankz , i hope this helps...

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Post by youdirtyrat »

biliousfrog wrote:Slow day today so I just put another coil in the Tele for the neck pickup :?
so if thats the case on tele? im gonna have to put 3 dummy coils for my strat?

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Post by biliousfrog »

youdirtyrat wrote:
biliousfrog wrote:Slow day today so I just put another coil in the Tele for the neck pickup :?
so if thats the case on tele? im gonna have to put 3 dummy coils for my strat?
No, read through the links and this thread.

A strat usually has a reverse wound, reverse polarity middle pickup which offers hum cancelling in the in-between positions. If you add a dummy coil (which blocks hum in the same way as the in-between positions) you'd lose the hum cancelling properties when using those positions and it wouldn't work in the middle position. My Tele has a RW/RP neck pickup.

The solution is either:
To add a toggle switch (see my previous link) to turn the coil on/off
Use a "super switch" to enable the coil only in the 1 & 5 positions (possibly reversed in the middle).
Use another coil for the middle (2 in total)
Replace the middle pickup with a standard wound/polarity one and use the coil on the switch output (hum cancelling on all positions).

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