Why does my cable only seem to have a fault through my delay pedal?

[johnd]

My TC Electronic Flashback pedal suddenly started making a nasty repetitive clicking/popping noise yesterday. I was sure it was the pedal since when I turned it off (it has pass-through) everything works fine.

But today I found swapping the guitar cable fixes it. But since the 'problem' cable works perfectly when the delay pedal is turned off, no crackles or anything, how can this be? It worked fine until yesterday too. How can a cable only express a fault when the delay pedal is active?

My setup for testing is guitar > tuner > delay > practice amp. Taking the tuner out doesn't make any difference (even physically unplugging it).

It's a new PW cable so do I just get a replacement or could it be some weird problem with the pedal?

[HHP]

Jack socket?

[guitararmy]

I've read stories about people having problems with the plugs on the Planet Wave cables because they are shaped a bit differently than others.....

I still have one of the early ones with the expanding tip that I understand also can be an issue.

[jonfields45]

It is possible the cable is slightly microphonic and generating a small bit of noise. One reason low impedance systems are prefered is that these sort of noise sources are very high impedance and into a low impedance load the noise is largely dissipated at the noise source in its internal resistance. So if you're still with me, the nice new TC pedal probably has a very high input impedance as this is desirable matching it to a high impedance source like a typical passive electric guitar, which gives you the ideal setup to hear small noise sources in a marginal cable. Bypassing the pedal now puts the bad cable in series with another cable and looking into the input of the amp, which in total might be just low enough of a total impedance to swallow the noise glitch and also since there is no delay effect to repeat the noise, make it even harder to hear.

Return the cable!

Jon

[johnd]

Interesting. And the fact it was working previously and very suddenly went wrong? Does that support this argument or diminish it?

Obviously PW have a great warranty program and I bought from Amazon so replacing should be no issue.

[jonfields45]

I am sure they start with top quality materials and assembly processes, so I don't see any inconsistency with the cable going bad after use. Jon

[Scootch]

There is sometime a diffence in size between cables/jacks depending on if they are 1/4" or 6.35mm. Manufacturing variance, etc.

I have one cable plug that works on everything but one guitar. Every other cable works on that guitar. That cable plug must be at the upper size of the Margin of Error and the Jack must be at the lower end of the Margin of Error.

[johnd]

Originally Posted by jonfields45

I am sure they start with top quality materials and assembly processes, so I don't see any inconsistency with the cable going bad after use. Jon

I mean, rather than them using a bad batch to start with, how would the problem you suggest happen through wear and tear?

Originally Posted by Scootch

There is sometime a diffence in size between cables/jacks depending on if they are 1/4" or 6.35mm. Manufacturing variance, etc.

I have one cable plug that works on everything but one guitar. Every other cable works on that guitar. That cable plug must be at the upper size of the Margin of Error and the Jack must be at the lower end of the Margin of Error.

This cable works perfectly in other cases, and it even works plugged into the pedal in pass-through mode... and it worked yesterday. So I don't think that can be the issue here. An electrical issue (like Jon suggests) rather than a mechanical one does sound more likely.

I am just concerned that if I send it back, they might test it and not see any error since it works fine normally. So I wanted to double-check what could be the cause before blaming PW and sending their cable back

[clintj]

Try plugging it in the opposite way - IOW switch which end is in the guitar. Maybe one end is a little "off", and shows up when it is plugged into the pedal and not the guitar.

Bad things can happen to the best parts. Breakdown from flexing, dry or cold solder joints, oxidation, etc can all play havoc on good gear.

[johnd]

Originally Posted by clintj

Try plugging it in the opposite way - IOW switch which end is in the guitar. Maybe one end is a little "off", and shows up when it is plugged into the pedal and not the guitar.

I tried this and it DOES seem to remove the problem, I tried switching a couple of times and it's consistent.

But - I noticed on one end (It's a PW instrument cable) the jack says "shielded end". I'd never noticed this before or if I had assumed it was a feature of the cable like "oxygen free" or whatever. Is it possible the cable is not designed to be identical at both ends, and I was using it backwards without realising?

[BTF]

If one end is marked "Shielded End", that cable has a telescoping ground. It should have two conductors and a braided shield. The braided shield is only connected at one end of the cable. One of the center connectors provides the signal ground and local plug shield, and whatever device you plug into or come from provides a shield to the braid via its jack's ground connection.

It's designed to be quieter that way, but apparently it's causing trouble with your setup. I don't use that type of cable, but I have used it in rack builds between devices. Sometimes it works well, other times I've had to use regular cables.

[johnd]

It's not something I've ever heard of, but putting the "shielded end" jack into my pedals rather than the guitar, things seem to work well. So I'm going to assume my cable isn't faulty and maybe I somehow have only used the cable that way round previously, and the problems "started" when I flipped it round without even realising!

[jonfields45]

I had to look up Planet Waves on there website to believe it. In theory it has TWO shields with one of them only connected at one end. This is expensive snake oil and as you learned not even particularly robust. I personally would return that cable because of the hassle of determining which end needs to go where for your devices. Shielding from one end (ground lift) makes perfect sense in low impedance differential systems (mic cables) to avoid ground loops between devices separated by long cable runs and likely running off different AC outlets. Pasting some of that good feeling technology onto single ended cables is marketing nonsense. Jon

[ombudsman]

removed, redundant

[RockerDuck]

Cables can go bad in a instant. Especially for people who change their pedal board order around constantly and continually add and subtract new pedals..