Twisting wire together to reduce interference...

Boolywho
January 22nd, 2011, 06:59 AM
I'm wondering if the polarity of the wires matters when you are twisting them together to reduce interference? For instance, do you need to twist a negative (ground) wire with a positive (hot) wire, or could you twist two positive wires together and get the same result? How about two negatives and a positive (like the combo coming out of a tele bridge pickup).

Also, what is this effect called when you reduce interference by twisting wires together? I want to look it up but I don't know the its name. Thanks for you help!

sjtalon
January 22nd, 2011, 09:03 AM
Twisted pair cabling. It's an 'ol telephone cable trick

You would have to twist the pair of an individual circuit, id est, the positive and neutral of ONE pickup, for it to have effect.

You could say in theory it works with wire like a RW/RP pup works in a set, and only works with AC.

Bolide
January 22nd, 2011, 11:45 AM
For a twisted pair to have best results, both leads should have equal and opposite current flows. Twisted pair used to be readily available by the inch or shop spool, but some folk take two wires of same gauge with different insulator colors, anchor one end of the pair in a vise, clamp the other end in an egg-beater drill, and whirl slowly until they get the twist they want.

mefarri
January 22nd, 2011, 03:17 PM
I was going to twist the input jack wires because I heard that helps, but I hadn't heard about twisting the pickup wires. Is that something people do? I guess it would just be the positive and negative twisted together? What about a 4 wire humbucker?

rolling56
January 22nd, 2011, 03:33 PM
For a twisted pair to have best results, both leads should have equal and opposite current flows. Twisted pair used to be readily available by the inch or shop spool, but some folk take two wires of same gauge with different insulator colors, anchor one end of the pair in a vise, clamp the other end in an egg-beater drill, and whirl slowly until they get the twist they want.

For heavy gauge wires use a drill and put the wires in the chuck.

chrisgblues
January 22nd, 2011, 03:42 PM
I'm no expert, but I'm pretty sure that twisting the input jack wires is an attempt to have the ground wire act as a shield by wrapping itself around the hot wire. It would be even better if you left the hot wire straight, and totally wrapped it in the ground wire for it's entire length. Kind of like how George L cables are constructed...the ground is 'weaved' around the entire length of the cable effectively shielding the hot wire contained in the centre. So the ground 'shunts' away any RFI/EMI and reduces noise.

I'm sure there are other factors to consider. JMHO.

January 22nd, 2011, 05:43 PM
Woven

dsutton24
January 22nd, 2011, 06:22 PM
Twisting wires to reduce audio hum is only effective with very long wires. If you've got something that is picking up a nearby strong radio station then it can help. On the other hand, it can't hurt either. It's the sort of thing you can experiment with without consequence.

donh
January 22nd, 2011, 06:27 PM
Twisting is effective even with short runs, and mutual twists are far more effective, especially in a balanced run, than trying to make one side the shield.

If you wish to make one side a shield, go to full-shield cable - it's different.

The theory makes it obvious, please feel free to look it up.

dayold
January 24th, 2011, 06:04 PM
I always twisted to feed them through the body routes.

The sound man in our band INSISTED that the lights / PA and stage a/c was separated and wrapped a certain way to avoid interference.

..so the wrapping at least works for sound and power cords because we never had 60 hum or buzz. ..or got shocked.

Jack S
January 24th, 2011, 06:18 PM
Two wires running parallel to each other in close proximity with current passing through one or both can set up an EM field. Twisting them together effectively contains the EM field. It does not have to be AC to be effective.

Telephone wires are bundled in groups of 25 pairs, each 25 pairs are sub-grouped into five pairs. Each pair is twisted and there is a slightly different twist (turns per inch or foot or whatever) so that no two pairs of wires in a bundle will lay side-by-side with the same twist to prevent creating an EM field between adjacent pairs. This was done to prevent cross-talk in cable bundles. If cross-talk does occur, it is generally due to some defect, or potentially water in the cable.

dsutton24
January 24th, 2011, 08:02 PM
Twisting is effective even with short runs, and mutual twists are far more effective, especially in a balanced run...

Guitar wiring is not a balanced audio circuit. Twisting wires in an unbalanced system can actually worsen hum, especially if you're fighting an common-mode ground loop. Ever touch a single coil pickup and had the hum increase? Of course you have. We all have.

I've been a broadcast engineer for 30+ years. I've seen every type of audio distortion that ever was, and hum is probably the most common. Almost every case of induced hum is due to poor practice, not materials issues.

donh
January 24th, 2011, 10:39 PM
Ever touch a single coil pickup and had the hum increase? Of course you have. We all have.

LOL!

If I find that condition, I fix it!

They way I wire them, it's a non-issue. As it should be.

And pickups are a balanced kinda thang. They are typically wired into electronics in an unbalanced configuration, but that is a subject for another thread.

I am sorry that twisting wires fails to work for you. some of us find it really really useful anyhow.

dsutton24
January 25th, 2011, 08:18 PM
I am sorry that twisting wires fails to work for you. some of us find it really really useful anyhow.

There are a lot of things that don't work for me. I once did a Hendrix-upside down thing for a lefty, making it a Right Side Up Upside Down, I think. For some reason that project left scar tissue in my brain that is probably permanent.

I do not think twisting makes much, if any difference, but I did (also) say earlier that there's no harm in experimenting with it.

It's so easy to over complicate this stuff, it's a wonder anybody would take up instrument repair or building as a hobby. Knowing what advice to follow and what to ignore is strictly personal preference, and by all means ignore my advice any time it seems to be less than helpful. I don't have all the answers, but like most here I do have a fair amount of experience that might be useful to someone on occasion. I'm also not the one investing time or money in your project, so the end result is always your work.

tdowns
January 25th, 2011, 11:27 PM
This is quite a divergent set of posts. Linked below is an explanation I posted on twisted pair wiring nearly 3 years ago. I hope it helps converge this topic.

Twisting wires help reduce tele huml (http://www.tdpri.com/forum/tele-technical/100422-twisting-wires-help-reduce-tele-hum.html)

Boolywho
January 26th, 2011, 03:41 AM
Thanks for the helpful post Terry,
I am using noiseless pups, and I do plan on shielding the guitar, so I'll go ahead and twist the wires too. One quick question though...

You said that the opposite polarity of the two twisted wires is essential for the hum reducing effect. So what happens when you have three wires? I'm wondering because I don't know what to do with my bridge pickup, which has a positive and negative wire, as well as a ground wire for the baseplate.

Do I twist the positive and negative wires together, and then run the single ground wire separately alongside the twisted pair? Or can I still just twist them all together as a trio? Thanks again for your input!

sjtalon
January 26th, 2011, 09:09 AM
You have noiseless pickups, why are you going to shield ?

I think some people go nuts with this shielding stuff just because they read you should do it ( as if you HAVE too).

SOMETIMES shielding has effect on the pickups tone, so it's one of those things that you should only do if necessary.

Twisting wires and some of the other voodoo stuff you hear about gets blown out of proportion I feel.

Too each his own but the best thing to do with a guitar is play it.

tdowns
January 26th, 2011, 10:11 AM
......

Do I twist the positive and negative wires together, and then run the single ground wire separately alongside the twisted pair? .....!

Yes, although it will liklely not make much difference

You have noiseless pickups, why are you going to shield ?

I think some people go nuts with this shielding stuff just because they read you should do it ( as if you HAVE too).

SOMETIMES shielding has effect on the pickups tone, so it's one of those things that you should only do if necessary.

Twisting wires and some of the other voodoo stuff you hear about get's blown out of proportion if feel.

Too each his own but the best thing to do with a guitar is play it.

If you have noiseless pickup, the wiring in the guitar is the only thing left with susceptibility to power line fields. It's really the only time shielding and twisted pair matters. If you read my linked post above, it gets into that.

sjtalon
January 26th, 2011, 11:03 AM
I'm going to give that a good read, I have a small mind so it shouldn't be hard to open it a little.

boris bubbanov
January 26th, 2011, 12:09 PM
:grin:

Every time I do the twisted leads thing on a guitar wiring job, I decide after the work is done that one pickup or another sounds wrong for the guitar, anyway.

:oops:

tdowns
January 26th, 2011, 09:55 PM
You have noiseless pickups, why are you going to shield ?

.......

It's kind of like saying that if you install noiseless pickups you don't need a shielded guitar cable. If you are using single coils, it's gonna hum no matter what. Shielding may help some depending on the environment and noise source(s). But if you make all that major noise go away with noise cancelling pickups, you might as well go all the way and fix the little things to get the best you can in noise reduction.

Also, if you completely shield the control cavity, that twisted pair to the jack isn't affected anyway, so why twist it?

I don't think I said it well, I don't think twisted pairs are much help in a guitar. But it is a well known, well studied, and often used technique in the electronics industry to reduce noise pickup.

I'm going to give that a good read, I have a small mind so it shouldn't be hard to open it a little.

Not believing the small mind part!!

mefarri
February 13th, 2011, 03:18 AM
I'm bumping this thread for a question on 5 conductor humbucker wiring as far as twisting goes.

I have a Duncan Custom and it has 5 wires in it's sheath. Green and a bare wire go to ground, black is positive, and a red and white that go to my DPDT switch for coil splitting.

Above, I read what I should do with the neck pickup that I've modified for series wiring by lifting the pickup cover ground and soldering a new wire on. You would twist the hot and negative of the pickup together and then just run the pickup cover's new dedicated ground along side those 2.

Right?

Now to my original question, How would I twist those wires together to reduce hum like the neck pickup?

thanks guys.

sjtalon
February 13th, 2011, 09:15 AM
Now to my original question, How would I twist those wires together to reduce hum like the neck pickup?

thanks guys.

You wouldn't necessarily have to as they are shielded (in the bare sheath), so there wouldn't be any interference induced in them. That deal works like coaxial cable (TV cable).

On the other, just twist the + & - and have the cover wire separate if that floats your boat.

mefarri
February 13th, 2011, 01:41 PM
Ahhh I see. It does look like the 5 wires are twisted a little inside that sheath. I guess that's accomplishing what I'm asking for. Thanks for the help.

Bolide
February 13th, 2011, 01:50 PM
Twisted pairs are best with two wires having current flow that is equal in magnitude and opposite in direction. Anything more complicated than that and you fast approach the need for a supercomputer to simulate the behavior of the currents in the wires and their interactions.

So, for a humbucking pickup you might twist the wires from one coil as a pair, the wires of the other coil as a pair, and just let the bonding lead tag alongside by itself.

BobUrban
March 22nd, 2011, 12:29 PM
Whether twisting the wires rejects hum or not in your guitar, you can make a case for it simply because it is neat and tidy, helping to prevent control cavities and pickguards from looking like spaghetti.