Help with loss of one channel in a TRS 3.5mm-3.5mm
Jan 18, 2011 at 4:44 AM Thread Starter Post #1 of 10

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In all my experience of cable making, I've never come across something like this before. I have made a 3.5mm-3.5mm cable using 20AWG SPC and Neutrik plugs (though the only shop I have access to that sells things like these only sells the China-made 'Neutriks')

However, when I plug in the cable into my iPod and into an amp (I verified this with a speaker setup so the fault lies solely with the cable), the right channel doesn't come through at all.

The weird thing is, both channels DO come through (with perfectly fine sound quality and with the left side's volume level undiminished) if the plug (on the audio-in side, either going into the speakers or into an amp) is is only inserted halfway, which signifies that there isn't anything wrong with the soldering joints, if I'm not wrong.

Would anyone be able to tell me what may be the matter with my cable? ><
 
Jan 18, 2011 at 5:09 AM Post #2 of 10
Unscrew the cases, and try again, I bet your shorting inside
 
cheers
FRED
 
Jan 18, 2011 at 5:19 AM Post #3 of 10
Both have a channel insulated with heatshrink inside, and if a short was the problem there shouldn't even be sound in the first place, isn't it? Or have I gotten some misconceptions as to how the signal travels.
 
EDIT: Just unscrewed the covers, cut open the heatshrink and doublechecked both sides, all the wires/contact points are not in contact with each other or insulated with heatshrink. No excess solder as far as I can see, problem still remains.
 
Jan 18, 2011 at 9:51 AM Post #4 of 10
Bump. And I checked the plugs and realized that one plug was slighttllyyyy shorter than the other, by perhaps 0.3-5mm or so (stupid Chinese QC). Which might have been the problem due to the ring connector not contacting with the jack's contact, but this was complicated by the fact that I reversed the cable and had the same problem/stopgap solution.
 
Jan 18, 2011 at 3:35 PM Post #5 of 10
I don't see markings on your individual cables you sure you have it wired the same internally on both end?  Maybe you mixed up the right channel and ground on one end?
 
Do you have a multimeter to check the connection?  You should get 0 resistance from tip to tip, ring 1 to ring 1 and sleeve to sleeve.  Ring 1 is the right channel, so focus there.  It should get infinite resistance if you cross any of those, so touching tip to sleeve should be infinite.   If say you mixed up right to ground on one end then you should be able to determine that with the multimeter.
 
Pulling the connector partway out of a jack shorts the right channel with ground, so if that fixes it then maybe your right channel is going to ground...
 
Jan 19, 2011 at 12:39 AM Post #6 of 10
I agree with peppe.  You would be able to solve this mystery in a jiffy with a multimeter.  Check the cable for continuity through the each wire and each plug.  Check for unexpected continuities from the tip, ring, and sleeve of one plug to those of the other plug.  Basically just narrow it down until you find the root of your problem.  Simple!
 
I only use neutrik minis in my cables and whether they're Neutrik or Rean-branded, I haven't had any problems with quality.  I would be surprised if that were the issue.
 
Jan 19, 2011 at 7:19 AM Post #7 of 10
Ahh I see. Thanks so much! Will try doublechecking the wiring connection, though I don't have a multimeter so I guess I'll just have to improvise.
 
Jan 19, 2011 at 10:39 AM Post #8 of 10
You can make a continuity tester with a 9V battery, a LED, a resistor, and some wire. Its probably not safe for drivers, but if your just checking a wire it should be fine*
 
OTOH, a multimeter is easier to use and only a hair more expensive. If you are planning to do this more than once or twice its totally worth the expense. If you ever plan to work on headphones its mandatory.
 
* Its hard to talk about cables without making a cheap joke so I put it at the end: I accept no responsibility for possible changes in sound as a result of DC current flowing through signal wires. If you like the sound as a result of this "treatment" I of course accept full responsibility.
 
Jan 19, 2011 at 1:13 PM Post #9 of 10


Quote:
* Its hard to talk about cables without making a cheap joke so I put it at the end: I accept no responsibility for possible changes in sound as a result of DC current flowing through signal wires. If you like the sound as a result of this "treatment" I of course accept full responsibility.

:rofl:
 
Meters that are actually useful are so cheap these days. Even the $4 one from Harbor Freight is perfectly adequate for many uses:
http://www.harborfreight.com/7-function-digital-multimeter-90899.html
 
 
Jan 19, 2011 at 1:15 PM Post #10 of 10
I made a cable once, with one strand of wire going over to the other channel.  I couldn't see it, but my multimeter picked it up.  Further examination with a loupe made it clear.  I cut the strand of wire with a xacto knife, and then covered it with heatshrink.
 
Those fine wires sure do get tricky at times.  They were coated strands so it wouldn't show up with a continuity test until the coating was melted off.
 

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