Weird Cable problem

[jkokura]

I put a new end on a cable. It's a Neutrik NP2X, at least I think that's the code.

Anyway, it's a short cable. Maybe 8 feet long at most. Thing is, it sounds weird. The volume's all gone with it straight into my amp, and it sounds like my tone knob is at 0. I have a dark sounding guitar but, this is a little out of hand.

But, when I turn any kind of pedal on - PRESTO - sounds normal again. Straight into the amp, the cable sounds no good. With an active pedal on it's fine. I discovered it because I was trying to shoot a pedal demo, and my bypass signal really sucked. I thought it was just cause the pedal I built was super awesome, but I double checked the two cables and this one cable absolutely was causing me problems.

I thought perhaps there's  break in the cable somewhere, but that wouldn't make sense to me because turning an effect on made the problem disappear.

Any ideas?

Jacob

[ashcat_lt]

Measure the resistance and (if possible) capacitance between tip and sleeve on one end of the cable while the other end is disconnected.

[jkokura]

I will, thanks for the suggestion. What kind of readings should I be getting? What should I do if I get 'bad' readings?

Jacob

[PRR]

> What kind of readings should I be getting?

I think you know enough electricity to guess the basics.

Two conductors, center and shield.

Each conductor should be very low resistance end-to-end. For 8 feet of anything metal, probably under 1 ohm. 10 or 100 ohms won't affect your signal, but means something isn't right.

From one conductor to the other, using DC (standard ohm meter), should be very high. In this case, far-far more than 200K or it will load the guitar's top end. With modern plastics we expect hundreds of Meg-Ohms across a short dry cable.

On standard DVMs, these will read zero and Overload.

Capacitance for dang near any cable is 30 pFd per foot / 100pFd per meter. Very skinny center conductor (or insulation too fat to be useful on stage) may get below 16pFd/foot. Some special cables (not intended for guitar or audio line-level) may approach 50pFd/foot. So in 8 feet you expect 200pFd-300pFd.

> when I turn any kind of pedal on

At WHICH END of the cable? Driving it? Or receiving from it?

Literally ANY pedal? Or just handy ones?

If some-HOW you got 10K from center to ground, a naked guitar pickup's bass would pass slightly-weak but the treble would be clobbered; yet most strong (active, buffer) sources would feed fine and flat.

I'd like to know what you did, because I can't figure any simple explanation.

[Nasse]

Sometimes there is conductive plastic layer somewhere there to reduce static electricity noise....

[ayayay!]

That sounds to me like you're using speaker cable instead of instrument.  Speaker cable has two insulated leads side by side.  Instrument has an insulated center lead, and a braided (think coax) sheild. 

Mebbe I'm wrong. 

[jkokura]

That sounds to me like you're using speaker cable instead of instrument.  Speaker cable has two insulated leads side by side.  Instrument has an insulated center lead, and a braided (think coax) sheild. 

Mebbe I'm wrong. 

Sorry, you are. This is a guitar cable. I simply replaced an end yesterday - I've used this cable for years. It should work, and I've closely inspected the solder job I've done. I don't understand it, but I'll get out my DMM and take some resistance and capacitance measurements and get back. Thanks for the advice, and if anyone knows what's going on, feel free to share!

Jacob

[MikeH]

Sometimes there is conductive plastic layer somewhere there to reduce static electricity noise....

Yeah, mogami cable has a black layer in between the shield and the insulation that's on the center lead.  That stuff is conductive, but only kind-of conductive.  If that layer is touching your hot lead than it will make funny stuff happen.