cable wiring question

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antichef

antichef

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Last night I opened up Somnium7's DIY patch cable thread and lovingly made four beautiful 3' TRS patch cables that would go between my ACMP preamps (when they arrive) and the waiting audiofire 12 unit. Like knitting for an expected baby :D

But this morning I opened up Chance's page again, and noticed that the output from the ACMP 73 (and presumably the others) is XLR! :o:eek::o

So I'm here "asking for a fish" (rather than asking to be taught how to fish) -- does anyone know the correct pin association for an XLR female to TRS cable?

My assumption is that XLR pin1 would be the shield, XLR pin2 would be the tip, and XLR pin3 would be the ring, but that's just a guess -- is it right?
 
Last night I opened up Somnium7's DIY patch cable thread and lovingly made four beautiful 3' TRS patch cables that would go between my ACMP preamps (when they arrive) and the waiting audiofire 12 unit. Like knitting for an expected baby :D

But this morning I opened up Chance's page again, and noticed that the output from the ACMP 73 (and presumably the others) is XLR! :o:eek::o

So I'm here "asking for a fish" (rather than asking to be taught how to fish) -- does anyone know the correct pin association for an XLR female to TRS cable?

My assumption is that XLR pin1 would be the shield, XLR pin2 would be the tip, and XLR pin3 would be the ring, but that's just a guess -- is it right?

The answer is at the bottom of this message-in bold print----

Wiring your own cables:

There's no big trick to building your own cables. Soldering is pretty easy, and just takes a little practice. The first thing to do is to select an appropriate type of wire. An XLR or 1/4" TRS cable will need 2 conductors plus a shield, and a 1/4" TS cable will need 1 conductor plus shield.

You must also choose the right type of shield for your application. Foil shields provide better hum and noise rejection, but they are only good in a fixed installation (something that won't be moved often - behind the rack, or in a wall). Braided shields are more flexible, and can be used for mic, instrument, and patch cables. Get the highest percentage of shield coverage as possible.

I always use heat shrink tubing and high quality connectors. Neutrik and Switchcraft are fine choices. I put heat shrink tubes over each terminal in the connector... this prevents the possibility of them ever becoming shorted if the cable is strained hard.

To build a cable, you chop off the appropriate sized piece of wire, and strip both ends. Generally, you'll strip the outside jacket back about 3/4" to 1". Twist the shield wires together neatly, and tin them with the soldering iron. Strip back about 1/4" to 1/2" of the inner conductor. Twist it neatly, and tin it. Repeat for each inner wire.

Now you slip the barrel of the connector over the wire, and put heat shrink tubing on each wire (just slip it on, don't heat it yet). If you're making XLR's, make sure you put on the strain relief before soldering, too. On 1/4" connectors, I usually solder the tip and sleeve connectors first, and the shield last. The layout of XLR's make them easy to solder in any order. When you solder connectors, you'll need a relatively big iron to heat the terminals sufficiently. When you're done soldering, use a heat gun to shrink the tubing over your connetions, then close the barrel. When you've finished, use an ohmmeter to test them for open circuits, miswiring, and shorts.

And, just so you don't get your wires mixed up, here's what each conductor is for both types of balanced connections. You can also make your own XLR to 1/4" TRS wires to connect your gear.

XLR:

Pin 1 - Shield (Ground)
Pin 2 - Hot (+)
Pin 3 - Cold (-)

1/4" TRS:
Tip - Hot (+)
Ring - Cold (-)
Sleeve - Shield (Ground)
 
Thanks!!! I'm a cable making fiend now.

One more somewhat related question -- the local electronics store sells 4 conductor microphone cable (that is, braided shield + 4 internal wires) that I guess is used for snakes? I have a guitar modeling thing that has two balanced line-level outputs that are intended to be run to a board somewhere. Rather than using two long balanced cables, is it thinkable to splice this 4 conductor thing into two TRS plugs on either end? Sort of a ghetto two-channel snake?

I can see how there'd be an issue of running the shield out properly to the two TRS plugs, but it would be awesome to tote around and deploy one long cable instead of two long ones.
 
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