Check Those Cables!

[Paul Marossy]

I had a weird cable related thing that came up that I thought I'd share.

I have this old Polysix that I've restored to 100% and I like to use it for nice pad sounds while I experiment with lines over certain chords and stuff. I recently had to go back inside and fix the PCB (again) where the battery had leaked out potassium hydroxide and it ate some of the smaller PCB tracks after I thought I had it taken care of.

Anyway, the last week or so, I would have the unit holding various chords while I practice my guitar and at about 45 minutes or so, the sound would just suddenly cut out. So I figured that it was probably the CPU in the unit which freaked out, so I turned the unit off an on again and that seemed to work once, but not the next time it happened. Or that it was maybe some bad electros in strategic locations. So I looked at the schematics, picked out some caps in various places that I thought might be the culprit and changed them all. After I changed all the ones on the power supply board, I thought the problem was solved - until the sound mysteriously cut out again. But this time, I suspected my cord was the problem, and sure enough it was! This was a surprise to me as the cable just sits there statically, it never moves and there is no stress on it because it stays put between the keyboard and the mixer. Now this cable is one of these RadioShack coiled cables that I got a long time ago and I only used it to connect stuff together in the studio. Now the odd thing about it is that it was pretty consistent at about 45 minutes it would sometimes cut out. So the next day I dissected it to see what was going on, and it was the tip wire inside broke. So I surmise that it must have been a temperature related failure. As my room warms up in the morning, the rubber surround must have expanded at a greater rate than the copper, and at about 45 minutes, wham! Never even crossed my mind!

So all that to say that one shouldn't immediately assume that the equipment is at fault (even if it is a unit that is 31 years old).   This is not to bash RadioShack, it's just to say look where you don't expect a problem. Sometimes that's where it is!

[Morocotopo]

Cords work in misterious ways.



Once I had one oxidize (the shield) in such a way that it "swamped" the sound, not just loss of highs but a very strange defocusing of the sound. Come to think of it, it was an FX in it´s own right!

Other weird stuff: a patch cord, about 20 cm. long, that totally obliterated the highs, I mean like closing the tone control on the guitar... imagine the capacitance per meter of that thing. Could have used it to filter power ripple in some effects. And it was made from a brand name cord!!! (Fendcough cough cough...)

[Paul Marossy]

Cords work in misterious ways.



Once I had one oxidize (the shield) in such a way that it "swamped" the sound, not just loss of highs but a very strange defocusing of the sound. Come to think of it, it was an FX in it´s own right!

Other weird stuff: a patch cord, about 20 cm. long, that totally obliterated the highs, I mean like closing the tone control on the guitar... imagine the capacitance per meter of that thing. Could have used it to filter power ripple in some effects. And it was made from a brand name cord!!! (Fendcough cough cough...)

Weird!

[Processaurus]

I had used a guitar cable (one of the cloth wrapped fender ones) someone had left at my recording studio/corner to connect one of the studio monitors for a couple months, and thought I'd gotten screwed in the monitor deal because after a while of listening closely to things i noticed this cruddy, high frequency distortion in the right monitor.  Tried switching the monitor outputs from the soundcard, which didn't move the problem, but of course didn't move the cable because HOW COULD A  GUITAR CABLE MAKE DISTORTION?  Went as far as tracking down new tweeters for the monitors, but never got them because the problem mysteriously disappeared in some studio reshuffling.  At some later point the guitar cable was being used for guitar into an amplifier, and I was about to tear the amp apart because it sounded so crappy and fizzy distorted and wasn't capable of a good clean sound.  Until I remembered it was THE SAME CABLE. 

Really curious what electrical phenomenon was at work inside the cord/connectors, but it got chucked because of the heartache its curse had caused.  It didn't cut out, or add noise, or roll off highs, like any normal bad cable, it just made everything sound crappy.

[Mark Hammer]

My first PC was a British single board whose insides looked like this:

Unfortunately, the power-supply regulator was on the main board, and likely insufficiently heatsinked, thermo-gooped, or both.  In short order, the board developed a heat-related fracture.  It would not boot...until the board got warm enough, the traces expanded, and the hairline fracture/s on one or more of the address or data lines closed.

I ended up having to use it by keeping the chassis unscrewed, and keeping a hair dryer on hand.  Every morning when I got to the office, I had to warm up the machine with the hair dryer, before putting the cover back on.  Yes, I had to wait for my computer to "warm up".

Electrical continuity is a cruel cruel mistress!

[PRR]

> Yes, I had to wait for my computer to "warm up".

Scott Mueller tells a different tale. He loves PCs. He loves cars. He was doing computer car diagnostics long before it was common. He kept a then-old Compaq Portable PC in the garage. In the upper midwest US. It gets cold there.

The Compaq is a stunningly well-built machine, but not made for cold. The high ESR of cold caps foiled the switching power supply. It would not power-up. However it did dribble some current. After 10-15 minutes, he could switch off switch on, and now it would be fine.

[Paul Marossy]

I had used a guitar cable (one of the cloth wrapped fender ones) someone had left at my recording studio/corner to connect one of the studio monitors for a couple months, and thought I'd gotten screwed in the monitor deal because after a while of listening closely to things i noticed this cruddy, high frequency distortion in the right monitor.  Tried switching the monitor outputs from the soundcard, which didn't move the problem, but of course didn't move the cable because HOW COULD A  GUITAR CABLE MAKE DISTORTION?  Went as far as tracking down new tweeters for the monitors, but never got them because the problem mysteriously disappeared in some studio reshuffling.  At some later point the guitar cable was being used for guitar into an amplifier, and I was about to tear the amp apart because it sounded so crappy and fizzy distorted and wasn't capable of a good clean sound.  Until I remembered it was THE SAME CABLE. 

Really curious what electrical phenomenon was at work inside the cord/connectors, but it got chucked because of the heartache its curse had caused.  It didn't cut out, or add noise, or roll off highs, like any normal bad cable, it just made everything sound crappy.

Ha ha, that's weird stuff!

[Paul Marossy]

Sure is nice not to have the sound suddenly cut out after a while! Lovin' it.