Strange guitar lead problem

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Babaluma
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Strange guitar lead problem

Post by Babaluma » Thu Sep 18, 2008 6:23 am

i make all my own balanced and unbalanced cables for the studio. i use mogami instrument (unbalanced) and mic (balanced) cable with neutrik connectors for all my mic and line level gear.

recently i decided my guitar cable was old and made a new one, lovely mogami cable and gold plated neutrik connectors, shorter than the old shop bought cable i had been using, for better quality.

but after i'd soldered it together and plugged it in i immediately noticed a drop in level compared to my old cable. not only that, but the volume control now goes from fully on to off in about 10% of the volume pot's travel. the tone control hardly makes a difference at all. none of this occurred with my old cable.

i'm using a fender custom tele HH with coil tap, into a fender champion 600 reissue tube amp.

when i use the same parts to make the same type of cable for my line level gear, all seems to be fine. when i use the same cable to go direct into my avalon U5 all is fine. i'm wondering if it's something to do with the cable/tube amp interface, maybe an impedance mismatch?

any ideas? it's very weird.

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Re: Strange guitar lead problem

Post by vxboogie » Thu Sep 18, 2008 6:50 am

Babaluma wrote:when i use the same parts to make the same type of cable for my line level gear, all seems to be fine. when i use the same cable to go direct into my avalon U5 all is fine. i'm wondering if it's something to do with the cable/tube amp interface, maybe an impedance mismatch?

any ideas? it's very weird.
Have you metered it to make sure you have good connections and no shorting? Also, are the 1/4" plugs tip/ring/sleeve or just tip/sleeve?

I wouldn't think that the cable impedance would be an issue.
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Post by RodC » Thu Sep 18, 2008 7:19 am

Check to make sure you dont have one small strand of the shield that didnt get pulled back and is touching the +.

Is it good cable? Crappy wire shows itself with high impedance sources much faster. Normaly it has much more noise and you will hear more noise or a tone difference when you grab it with your hand. Those thin free cables from banjo mart come to mind.
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Post by jv » Thu Sep 18, 2008 8:05 am

If you don't already have one, you should get a multimeter (anybody who makes their own cables should have one, even a cheap one will do, it can save a lot of headaches). The resistance between the parts that should be connected (tip to tip, sleeve to sleeve) should be very low (less than 1 ohm). The resistance between parts that should not be connected (sleeve to tip) should be very high (higher than whatever the highest measurement on the meter is probably). I'm guessing it's what Rod said, a small strand of wire is shorting somewhere. Or you have a bad solder joint somewhere.

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Post by Nate Dort » Thu Sep 18, 2008 8:37 am

Mogami (and Canare for that matter) instrument cable has a black jacket over the center conductor for extra shielding. What they don't tell you is that it's partially conductive and can't contact your hot lead. You have to strip back that black covering away from the center conductor and leave just the clear insulation and the exposed copper tip for soldering.

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Babaluma
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Post by Babaluma » Thu Sep 18, 2008 7:32 pm

thanks for all the replies.

the plugs are tip/sleeve.

i don't have a multimeter, so will try and get one. thanks for the hints on how to use one with cables when i do get it.

i will also take the lead apart and double check my work.

it's very good quality mogami cable.

there is no clear insulation on the hot/middle wire, only the thick black one. i can't believe the black insulation is conductive, that is crazy! conductive insulation? doesn't make sense!

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Post by Nate Dort » Fri Sep 19, 2008 5:27 am

Babaluma wrote:there is no clear insulation on the hot/middle wire, only the thick black one. i can't believe the black insulation is conductive, that is crazy! conductive insulation? doesn't make sense!
You may have a different cable than what I'm referring to. I use Canare more than the Mogami, but I know that Mogami uses the same outer shield around their center conductor.

Check out this thread, specifically the last post:

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=11213

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Post by johnny7 » Fri Sep 19, 2008 8:01 am

We had a strange lead problem once.
Our guitarist went off into the mixolydian and never came back...

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Post by RefD » Fri Sep 19, 2008 9:10 am

johnny7 wrote:We had a strange lead problem once.
Our guitarist went off into the mixolydian and never came back...
was he a harmonic miner?

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Post by digitaldrummer » Fri Sep 19, 2008 6:56 pm

Babaluma wrote: there is no clear insulation on the hot/middle wire, only the thick black one. i can't believe the black insulation is conductive, that is crazy! conductive insulation? doesn't make sense!
try scraping that black wire with a knife - you may be surprised. I had some Mogami mic wire where it looked like insulated wire, but in fact the coating came off (once you got it started) and as mentioned above, it is conductive and really screws things up.

Mike

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Babaluma
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Post by Babaluma » Tue Oct 21, 2008 7:20 pm

i found the problem, big time user error, and i just thought i'd report back to let poeple know in case they have the same problem.

i was using the regular neutrik straight plugs on one end of the cable, which i am used to soldering, but right angle plugs on the other end (for the guitar out), which i was NOT used to soldering.

on the straight plugs there are only two lugs, one for tip, one for shield, and it's extremely obvious which is which.

on the right angle plugs there are THREE apparent connectors. two of them look very similar to the two on the straight plugs, and one is a little metal flap you can pull out.

i automatically assumed that the ones that looked the same were the same, but WRONG! on the right angle plugs you need to use the obvious tip for the tip connection, and the little metal flap is the shield.

this was my mistake and a quick look on the neutrik website for the instructions soon put me right. i resoldered and voila, everything is ok now.

basically, a lesson in "read the manual"!!!

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