Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: phsyconoodler on May 28, 2010, 05:57:04 pm
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Does anyone have a schematic and layout for a cable tester.I need to make one.I know you can buy one cheap but I like to make stuff that lasts a lifetime.
It's for testing all kinds of cables and needs to have LED's.
Cheers!
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What kind of cable? 1/4", XLR, CAT5?
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My whole career was cables.
The only cable tester I ever owned was for ethernet.
Audio cables may be tested by ear, and also with ohm meter.
The KEY trick was: make cables right, and MARK bad cables when found.
If you feel the need:
Continuity is simple. Battery, LED, appropriate resistor, and jacks. Usually you put V R and LED in one end, a jumper-jack at the other end, so that you don't have to bring both ends together. (Easy with gitar cords, tough with in-wall wiring.)
Gross leakage is easy. If the LED glows without the shorting jumper, the cable leaks.
Subtle leakage is harder.
Reversed-pair is tougher. Often uses a diode to block reverse-connection. While a reversed guitar cord is very obvious to the ear (BUZZZZ), a reversed balance-mike cord sounds fine alone.
Intermittent opens and shorts are tough. You want a peak-stretcher. Or an ear-brain.
Ethernet is unlistenable, has so many wires, with whacky crosses, that I blew $89 for a simple sequential continuity/cross tester (now selling for $19).