# I have a microphonic instrument cable



## Budda (May 29, 2007)

How can I fix it, or should I just buy a new one? It's actually my brother's.

Thanks!

(this post reads like I was born yesterday - when it comes to microphonic patch chords... I was!)


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## keeperofthegood (Apr 30, 2008)

Budda said:


> How can I fix it, or should I just buy a new one? It's actually my brother's.
> 
> Thanks!
> 
> (this post reads like I was born yesterday - when it comes to microphonic patch chords... I was!)



kqoct maybe I was born the day before you but ... what's a microphonic patch chord?


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## jimihendrix (Jun 27, 2009)

microphonic (mechanically pick up and transmit external noises)

the patch cord acts as a microphone...you can hear the sound coming through the amp if you drag the cord on the ground or tap it with your finger etc...


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## Budda (May 29, 2007)

my cable picks up radio signal. it's kind of funny when it does happen, but i'd rather hear 100% tone haha.


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## mhammer (Nov 30, 2007)

That's not microphonic. That's just poorly shielded. There's a difference.


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## Budda (May 29, 2007)

cheers, mark! and here i was thinking I had my terminology down.

I believe it's the end I'm plugging into my guitar that's poorly shielded. I have a bin of old cables that just need fixing.

Somehow I doubt that the music store will shield and repair 5 or 6 cables *sigh*


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## keeperofthegood (Apr 30, 2008)

No... but you may get a buck or two for copper recycling :O


I keep a couple boxes. 1 for copper and 1 for aluminum. :/ one of these days I may actually get around to getting the boxes to the metal recyclers 

The other option, lots of times High Schools will do parts work for people at cost or free, its educational


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## Budda (May 29, 2007)

Hm. My friend was going to teach me how to solder and we were going to spend an afternoon fixing my cables, but then I moved for school lol.

I'm debating just selling the lot of them for some amount, and buying a decent cable that will hopefully not have any issues. I have at least 4 $20 cables just kicking around in various states of disrepair


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## mhammer (Nov 30, 2007)

Save them. They are reparable and all eventually useful for something.


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## Budda (May 29, 2007)

I'd like to have them repaired - there's at least $100 worth of cables in there lol.


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## mrmatt1972 (Apr 3, 2008)

Great way to learn how to solder! Buy a soldering iron and some solder and just do it. There are lots of "how to" sites about soldering on the internet. You have nothing to lose.


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## mrmatt1972 (Apr 3, 2008)

About the radio interference... Is it a long cable? The longer the cord the more prone to radio reception it will be.

On a side note: I once had a neighbor who had a CB in his truck. I got his broadcasts loud and clear through my stereo speakers (which were off!) at 6:00 am! Not particularly welcome when I was a hungover University student.


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## Budda (May 29, 2007)

it's a 15 or 20 footer. The plan was/is to learn how to solder by fixing the cables. Still need to buy my own iron and sodder - and have my friend come over for an afternoon (free time - that thing I technically should not have...) and show me how to do it. I'd like to be able to do my own pickup swaps at some point!


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## keeperofthegood (Apr 30, 2008)

Are the plugs molded or screw on? 

If they are screw on, you can give them the 20/20 and pre-guess the work needed. If the joints look solid and nothing is loose with a wiggle, you may have metal failure inside the run of the cable. That would mean more work to find and either making the cable shorter or doing a splice.

Finding a break inside the wire isn't hard, just takes a lot of words to explain simply. So give it the look-see first under the plug houses.


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## Budda (May 29, 2007)

I'll do that tonight


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## overdriver (Jul 24, 2008)

Budda said:


> How can I fix it, or should I just buy a new one? It's actually my brother's.
> 
> Thanks!
> 
> (this post reads like I was born yesterday - when it comes to microphonic patch chords... I was!)


IMO sell it to J Rock and buy a new one  Thats what Ricky advised any how.


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## Overt1 (Aug 31, 2009)

if it's just a soldering issue, you shouldn't need to spend money on repairs. just buy a soldering iron and learn how to use it and you can save yourself a ton of money. and you can even learn how to make your own cables too afterwards with the iron. soldering isn't hard at all.


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## keithb7 (Dec 28, 2006)

Search You Tube for instructions on how to solder. There are some great videos on there. It's simple, and the videos will give you the confidence you need to get started.


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## Budda (May 29, 2007)

overdriver said:


> IMO sell it to J Rock and buy a new one  Thats what Ricky advised any how.


this is very tempting, as Ricky does offer great advice.


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## Budda (May 29, 2007)

I opened up the cables so to speak, nothing was disconnected at the jack. I guess it's a break somewhere in the cable


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## keeperofthegood (Apr 30, 2008)

Budda said:


> I opened up the cables so to speak, nothing was disconnected at the jack. I guess it's a break somewhere in the cable


NOW the fun begins.

Faraday is credited with a "cage", a demonstration of a "skin" effect. Electricity and signals ride the outside of a conductive surface. So, the outer shield of a guitar cable is like that cage, any signals inside the cable ride the inside surface of the cable, and any signals outside will ride the outside surface. Thats the 5 cent story on shields and shielding and shielded cables.

WHEN the shield breaks OR when the wire breaks you create a new surface on which signal can run (center wire breaks are not necessarily system fails, they can be capacitive, passing AC and not DC signals).

When your cable is picking up outside signals, it is because those signals have found a pathway in. So, that is what you need to next look for. Once you have looked under the end caps at the soldering, the next place to look is the entire run of cable, for any breaks or tears or bulges or dimples in the cable. Any of these place could represent a place where the shielding has become damaged in some manner.

Following that visual examination (and knowing that what you are looking for is a new surface) comes the "lots of words" part. You need a signal source and a sniffer tuned to that source. (ok, I just chopped all those words off and simplified the rest some).

The short explanation is this. Where ever there is a break or damage to a cable, the surfaces there will either pick up or radiate signals. In essence they are like antennas.

:/ thats the easy part, the hard part is getting a sniffer. Having done a LOT of google for a circuit, I found nothing. Not something that people tend to build from scrach anymore I think. Though if I recall (need to re-learn this) I think a grid dip meter is a sniffer. However, I _think_ you can rent a device from Home Depot that should work. Not sure what they call them but they are used for finding wires inside of walls. Small signal generator plugs into the outlet or clips onto the lamp leads and you follow along the wall with the hand unit watching a meter or light or something. You can I think use the same tool with guitar cables, where the signal spikes strong is where the break is.

 Time for Mhammer or Wild Bill I think, I know it this far, but its been decades for me!


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## Budda (May 29, 2007)

Thank's KOTG (say that one out loud, sounds like cottage-y haha!)

I have to find the break, get the skin off and fix it. hm. :O lol


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## keeperofthegood (Apr 30, 2008)

This is why I said "shorter cable" when I said that. I find it is simpler to get two new jacks and live with two cables


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## Guest (Oct 16, 2009)

KOTG: that post reminds me of this prof I had in university. He was this old, cantakerous, Polish guy who taught Electric Fields in second year. We called him The Emperor. Tough nut in class, but outside he was actually a really nice guy to talk with.

We had beers with him one night and started telling us some crazy stories. One being how and why he became an electrical engineer. He was in the Polish army, conscripted at a crazy young age, during WWII. He was in a Comm team and one of his jobs was to disrupt German communications and power before the land forces would attack. So before the main army went in, his unit would go near the town where the German's were holed up and cut the power. And every time they cut the power they got shot at. He started to wonder: how on earth do they know where we are? How are they finding us along this long length of wire so quickly?

And in finding out the answer to that question he found out he liked this stuff and made a career out of it.

He liked to use expressions like, "That's like shooting a Howitzer at a canary" in class.

Fun guy.


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## keeperofthegood (Apr 30, 2008)

HAHAHAHAH That's a great one!


My dad built me a "lights and switches" board, it ran off house current, had fuses, and I could hook it up how I wanted. That was when I was 2, I learned to solder when I was 4, and I did my first repair (of a stove) when I was 5.

DeVry was fun, but that didn't last long. Only 8 months, and I had to "take a break" as I had run face first into life.

:/ too bad about those 10 or 15 years of blotted out memories I have now, but over the last year my thinking has gotten to the point it no longer feels like I am constantly thinking through molasses though I still cannot do complex maths in my head, Norton and Thevenin and the like make my eyes water just to review them BUT I can at least remember they are called Norton and Thevenin now, without needing to spend days on google trying to remember!! I was disappointed the CT was not conclusive, at least I am generally doing better. Not sure what of all the vities I am taking is helping the most, the Glucosamine is noticeable fast when I stop taking that (amazing that sand feel under the knee caps). And it feels good to hear with that hearing aid 

AND I do love to laugh and joke! Life is too short really. OI but don't get me started on squealing bus tires  I pull that hearing aid out SO FAST!


Oh and, yes, if you had two grid-dip meters you can use them. Use one as a signal source, and the other as a signal detector. :bow: I spent a bit of time with the University of Google looking that up.


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## Fader (Mar 10, 2009)

Or you could use a time-domain reflectometer.


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## keeperofthegood (Apr 30, 2008)

Fader said:


> Or you could use a time-domain reflectometer.


kqoct http://en.wikipedia.org/wiki/Time-domain_reflectometer

Interesting idea. 

But on eBay they appear to range from $200 to $2000 :bow: 


>_> You know, I bet them cable service truck guys carry those around with them. Bottle of beer and maybe you can get a "here, show me how that works with this here guitar cable"


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## Fader (Mar 10, 2009)

Old school method of locating the open conductor?

Short out one end with an alligator clip. Put an ohmmeter across the the other end. Select the annoying audio beep setting.

If you have continuity, gently stretch about 12 to 18 inches of cable at a time until you locate the break when the beeping stops.

If you start with with no continuity, then you wiggle and twist the crap out of cable a section at a time, until you get a tone, if your lucky.


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## Budda (May 29, 2007)

Fader, that sounds like a much better and easily doable alternative!

Now I gotta figure out when I can do that.


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## greco (Jul 15, 2007)

Budda...please keep us updated on how the cable repairs are going.

If you get too frustrated with it, I can do the work for you. But I agree that it would be far better to learn how to do this type of thing yourself. 

Besides, I'm not sure if the shipping costs to and from Kitchener would be worth it.

Just thought I'd offer.

Cheers

Dave


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## Budda (May 29, 2007)

Thanks Dave 

I have to talk to my solder-savvy friend(s) and see when I can get started. I wonder if my dad wants to buy me a soldering iron haha.

I have yet to take anything apart. I am thinking about testing my other cables out tonight, since I'm procrastinating anyway.


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## greco (Jul 15, 2007)

Good Luck with getting all of your cables back to a functional state.

Enjoy the process and the learning.

Cheers

Dave


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## keeperofthegood (Apr 30, 2008)

:wave: any news yet (said in the ARE WE THERE YET mantra style of every young person that ever was a young person).


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