Ct-20 15plug cable tester, experiences?

[Ravenbar]

I just ordered a CT-20 cable tester off Amazon(https://www.amazon.com/gp/product/B0972J2ZR9/?tag=controlbooth-20). It tests all kinds of cables, from HDMI and several USB variants, to Banana jack and Speakon(also Powercon seperately), all the way to 3 and 5 pin XLR.

My main shoirt term use for it is to test the questionable cable pile at the local HS. I'd also considered it in the past for personal tests of USB cables, and other random cables, as my hobbis are so widely varied that they range from blacksmithing to computer programming.)

One thing I'll likely be making for it are adapters to test 6-pin XLR(likely using the RJ-45 connections), although opening it up and changing out jacks is also an option(it supports up to 20 conductors, in 2 sets of 10), perhaps the DIN connector that does 3/5/7/8pins, as I've never seen a DIN cable in that format that I recall. 6pin XLR is what the stage intercom system uses for the wired headsets, although they've added in some wireless headsets into the mix as well. I know there's at least one suspected dead headset cable in the heap, and another that's been run over by scenery and definitely been compromised, as the wires are showing. I'd have ordered a M and F 6pin XLR connector to build adapters with it, but I only work at the school until the musical closes(I only do this show for them every year), and they wouldn'y have arrived until after the show. I may sacrifice the damaged cable for it's connectors to build a pair of adapters, as $13/ea and weeks to arrive is insane for XLR connectors.

Anyone given one of these cheap($60) cable testers a workout, and what are your thoughts?

 

[soundman]

I can't speak for that tester but I'd say you are on the right track with making adapters for unsupported plugs. RJ45 seems to be a very affordable way to go, I was on a factory tour a few years back and a major manufacturer had a big cable testing set up and still had RJ45 to END adapters for the one off and odd ball cables they were making. I thought I snapped a photo of it but I can't find it at the moment.

 

[TimMc]

It's a DC continuity test, so anything that needs verification of function for high frequency use (like, data?) will not be so tested. You probably knew that already, but for those at home....

It will find only open or mis-wired (pin swapped) connections.

What I found, running a regional sound/LX shop for over 20 years, is that most "failed" cables were not, in fact, defective or failed. Operator error of some kind, or connection to another cable or device that had failed resulted in our techs tossing them in the 'fix it' bin. But of the audio XLR cables, we still had cables that passed the tester, but delivered defective audio (hums, buzzes, snap/crackle/pop). We found the best tester for mic cables to be.... a Lightronics shoebox dimmer that used multiplex control (not DMX). It was REALLY REALLY PICKY about cables. Any cable that worked with this dimmer and its related controls would flawlessly pass audio.

The CT-20 will cull the obviously open or miswired conductors but only tells us what passed or failed this most rudimentary test.

I think it was Linus Tech Tips on Yootoob that bought a TDS tester that does all kinds of multi conductor cables - it was about $10k, IIRC, to test and certify HDMI and USB cables. Those have gotten cheap enough (unless it comes from Apple) to simply recycle suspect cables and replace them with new.

 

[Ravenbar]

It's a DC continuity test, so anything that needs verification of function for high frequency use (like, data?) will not be so tested. You probably knew that already, but for those at home....

It will find only open or mis-wired (pin swapped) connections.

What I found, running a regional sound/LX shop for over 20 years, is that most "failed" cables were not, in fact, defective or failed. Operator error of some kind, or connection to another cable or device that had failed resulted in our techs tossing them in the 'fix it' bin. But of the audio XLR cables, we still had cables that passed the tester, but delivered defective audio (hums, buzzes, snap/crackle/pop). We found the best tester for mic cables to be.... a Lightronics shoebox dimmer that used multiplex control (not DMX). It was REALLY REALLY PICKY about cables. Any cable that worked with this dimmer and its related controls would flawlessly pass audio.

The CT-20 will cull the obviously open or miswired conductors but only tells us what passed or failed this most rudimentary test.

I think it was Linus Tech Tips on Yootoob that bought a TDS tester that does all kinds of multi conductor cables - it was about $10k, IIRC, to test and certify HDMI and USB cables. Those have gotten cheap enough (unless it comes from Apple) to simply recycle suspect cables and replace them with new.

It also doesn't appear to test for shorted together wires, as it only tests one wire at a time.

If I make up RJ-45 tailed adapters, I've also got a couple of network cable testers I could use them with.

 

[FMEng]

It also doesn't appear to test for shorted together wires, as it only tests one wire at a time.

Sure, it tests for shorts. If two conductors are shorted, two lights will be on together.

 

[Ravenbar]

Sure, it tests for shorts. If two conductors are shorted, two lights will be on together.

That would depend on how the switch inside works. Assuming it's only switching on the one side of the indicator LED's that would be correct. If for some reason they switched both sides of the indicators, that wouldn't be the case, but I suspect your correct, as dual pole 10 throw switches are very expensive, and kind of pointless, unless this thing has some brains inside that it doesn't appear too.

Cheap things from China tend to even astound me as to how cheaply they could be made. I recently bought a Decade resistor box off AliExpress. Given the dimensions of the case, I expected through hole resistors inside, likely in a point to point wiring setup(I've got a lot of precision resistors in electronics grab bags for cheap, so hoped it was an easily upgraded item). Rather they made a circuit board, with built in contact wipers, and used surface mount resistors. The knobs are fastened from the back with a screw, allowing a detent spring/ball in a cast in bore into a custom faceplate. Oddly enough, they seemed to use a standard lower part to the case, creating a huge empty area behind the circuit board.

 

[Ravenbar]

'll also mention most if not al the cables I'll be tssting were originally sold from professional supplier, so any damage resulting in a lack of continuity means the cable should be retired, as the cable used met data specs when new.

 

[cbrandt]

We've used a similar unit before, and had no complaints. With the same proviso as above, that it only works for continuity. But it is a good quick check that covers a lot of cables, and even more with a few adapters.