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Electrical chord test?
Posted: 5 Apr 2001 1:31 pm
by Ky Ian
Just bought a volt meter and testing my chords. I'm getting readings all over the place. What should a normally functioning chord read on the meter? Any comments on chords with a long life?
Posted: 5 Apr 2001 7:58 pm
by Bill Terry
I'm not sure that's a real reliable way to check a cable, other than a 'go' or 'no go' check. As for a good cable, do a search on 'George L Cable' in this forum area and you'll get a lot of opinions and advice. A lot of folks, myself included, like the George L cable system.
I had a cable a while back that worked fine as far as output signal level, but I thought something was wrong with my guitar (elec. 6 string), it had no treble response at all. I swapped the cable and immediately got the tone back, so later I measured the cable DC resistance and I think it was like 1 ohm or less maybe, I don't remember exactly.
I also measured the capacitance, tip to sleeve, and read something like 100nF. This was a quality Belden cable, but several years old, so I guess it got walked on or a case rolled across it or something. A 'good' cable measured something like a 100pF.
Out of curiosity, I put together a crude PSpice (circuit simulation program) model of a voltage source with a source impedance (a pickup) and a load impedance (the amp input) with a 100nF capacitance in shunt to ground to simulate my 'bad' cable. I was astonished to see that the signal was attenuated about 25dB at 3kHz. Even though my model was very simplistic, that's a strong argument for low capacitance cables, one of the claims of the George L's.
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Posted: 5 Apr 2001 8:27 pm
by Keith Hilton
Bill, which Belden cable number do you like best for guitar cords? What is your opinion of compression screw connections as compaired to solder connections? What 1/4 solder jack do you like? Is it Switch Craft, or is there a better one you like?
Posted: 6 Apr 2001 6:42 am
by Bill Terry
Hi Keith, how's that 'bucket brigade' search goin???
I've used several different Belden wires over the years, but I used to try to find 8410 I think it was. It was a single conductor with a braided shield, and a bunch of that nylon reinforcement that Belden (and others) use. I liked the rubber jacket and the fact that it didn't stretch like some of the cheaper spiral shield wires. I also used 8412, 2 conductor with braided shield and nylon reinforcement. On that I just twisted the 2 center conductors together at the connector ends, making one heavier one. The 8410 and 8412 were more time consuming to prep for soldering because of all the layers of reinforcement and insulation, but that's what makes good wire I guess.
I started using the George L connectors and cable last year and I've had real good luck with them so far. I was always skeptical of the compression connectors but maybe they've gotten a lot better, and the advantage of quick repair and custom lengths without the hassle of soldering is a big plus. Evidently the cable itself is pretty low capacitance and low DC resistance, because it seems totally transparent to the audio signal. I don't know if it's audibly any better than any good quality soldered cable, but it's awful convenient. I notice a lot of steel guitarists swear by them.
I always used Switchcraft 280's, the ground sleeve and threaded base were all one cast piece so they didn't tend to break or loosen like the cheaper imported ones. I remember a thread about this stuff a while back and I think the 280's were a real common preference.
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Posted: 7 Apr 2001 10:49 am
by Keith Hilton
Bill, I ordered a bucket brigade to experiment with. I have not had time to open the package yet. I am most interested in using the bucket brigade as a type of oscillator, or resonator. This is a little different than a analog delay. I suppose you can guess, Bill, what I would want a oscillator and a resonator for?
Posted: 7 Apr 2001 7:45 pm
by Bill Terry
Hmmm resonator... you're not trying to build some kind of hitech b@njo are you?
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Posted: 10 Apr 2001 9:10 am
by David Rich
Make sure your meter is set to ohms. Measuring tip to tip, and sleave to sleave,you should get not more than a couple of ohms. i.e. zero ohms would be a perfect conductor.
Also measure tip to sleave as that could indicate a short. The meter should read infinity or OL (open lead). If you're touching the probes, it may read several million ohms.
Posted: 10 Apr 2001 11:45 am
by Blake Hawkins
When I test my cords with an ohmmeter, I always use a pair of clip leads to connect the test probes to the cord.
That way, I can wiggle the cord around to check for intermittent shorts and opens.
Posted: 10 Apr 2001 1:47 pm
by John Paul Jones
When I test my chords with a volt meter It will only respond to a g-chord and a d-chord.
JPJ<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by John Paul Jones on 10 April 2001 at 02:49 PM.]</p></FONT>