Guide: How to Make a High-Quality Audio Interconnect for Your PChardnrg - May 29, 2007
Making The Interconnect - The Phono (RCA) End:
This end is a bit more involved as you need to split the cable to the left and right channels, prepare the cable and sort out the Y-split. Don't worry though, it's all straightforward enough.
Cut the sheathing off, but this time a longer amount as you'll be splitting the cable. Some people take the sheath off in sections, others cut the sheath lengthwise and peel it like a banana. Whichever way you do it, try not to break the shield as it carries the signal aswell. Unravel the shield from any internal insulation.
I removed the papery-cloth insulation, but kept the string. I separated the shield into two equal parts and twisted them. So I ended up with the two signal core cables, two twisted shields, and two string bundles.
You can braid three or more cables together for strength, neatness, and maintaining the shielding. If you don't know how to braid, either look it up or ask your girlfriend/sister/mother/friend.
I used some masking tape to hold the new braided sections together while sliding over a piece of heatshrink. This length of heatshrink needs to be long enough to extend up into the phono connector, but not all the way up.
Before you commit to the heatshrink, it would be a good idea to test the cable for continuity. Use a Digital MultiMeter (DMM) either set to continuity beeper, or the lowest resistance setting and check the end-to-end connection from the jack plug to the bare cables at the phono end. I measured 0.7 ohms on each signal core, and I don't remember what the shield was but it was the same or lower. Matching the resistance means you have equal signal transmission on both channels.
I used a lighter to shrink these small sections of heatshrink which is ok as they will not be seen. Using a lighter can easily end up with a sooty/charred appearance to the heatshrink. You could also use a hairdryer or heatgun. After shrinking the heatshrink, I cut some short sections of the smaller size braided sleeving and slipped that up over the heatshrinked section. I put some doubled sided tape around the heatshrink nearest the Y-split for the braiding to hold on to.
I worked the larger braiding back down over the cable, and when it was in the right position, moved it back a bit to put some double-sided tape around the cable sheathing so the larger braiding could hold on to the cable near the Y-split.
I cut some of the larger sized heatshrink and slipped it over all the sleeving.
Then I made two short sections of the medium sized heatshrink and slid that over each split piece, heatshrunk those, then slid over the large heatshrink back up over the entire Y-split and heatshrunk that. This time I used a hairdryer as these lengths of heatshrink are visible on the final cable assembly, so a clean appearance is necessary.
Remove the masking tape and measure up the cable to the phono connector, you want to end up with the sleeving inside the connector and will probably end up with only a short piece of signal cable and shield protuding. Remember to place the connector barrel over the cable before soldering! Flux and tin the cables in the same way as before. I used a scrap piece of cardboard to avoid damage to the sleeving while being held in the crocodile clips.
And then the soldering process is pretty much the same, the signal cable goes to the centre terminal, and the shield goes to the larger outer terminal. I had to apply quite a lot of heat to the shield terminal on this connector. If you have a variable heat iron, turn it up to avoid melting the plastic insulating parts of the connector.
Finish up soldering, clamp it, screw up the barrel, do the other one in the same way. Once you're done it would be a good idea to re-test the continuity from end to end using the connector tips as the measurement points.