Star Quad Cable Wiring (Canare)
On 2/8/2018 3:43 PM, Mike Rivers wrote:
Wiring with star quad correctly when you have balanced connections is pretty simple electrically, but can be a little fussy mechanically. Pretend it's two-conductor shielded cable. I'll assume that it has two blue wires and two white wires. Treat the two blue wires together as one conductor and the two white wires together as the other conductor. The shield is the shield.
If you were wiring a TRS plug to another TRS plug, you'd connect the two blue wires to the tips, the two white wires to the rings, and the shields to the sleeves.
But you're connecting between balanced and unbalanced ports. The fact that it's star-quad is moot. It doesn't matter that you have two wires twisted together - they aren't going to do anything special for you.
On the TRS end, connect the two blue wires to the tip, connect the two white wires to the sleeve, On the T-S end, connect the two blue wires to the tip of one plug and the two white wires to the tip of the other plug. Connect the sleeve to the sleeve of one plug.
Try it like that. You'll have a bit of unshielded wire and no sleeve connection for one of the TS plugs, but that input will get its ground through the chassis as long as the other plug is plugged in. For consistency's sake, you could run another piece of wire from the sleeve of the "grounded" plug to the sleeve of the ungrounded plug, giving it a path to the TRS plug's ground.
If you get too much hum, you could try an alternative method and use one blue-white pair for each unbalanced connection:
Let's make the blue wires "hot" for the sake of discussion. On the TRS end, connect one blue wire to the tip, the other blue wire to the ring, and the shield to the sleeve. Then, on one of the TS plugs, connect one blue wire to the tip and a white wire AND the shield to the sleeve. On the other TS plug, connect the other blue wire to the tip and the other white wire to the sleeve. A jumper between the sleeve of the two TS plugs is optional, might be necessary, or might cause more hum.
This isn't a completely predictable thing and you may need to play around with lifting grounds or adding grounds.
Also, should I change out all of my star quad cable made for instrument
cable like guitar and bass with instrument cable? I have not noticed any
signal degradation and zero hum but more testing might be in order.
Don't fix it if it isn't broken, but make sure it's not broken, or, alternatively, even if it's not broken, could it be better? This is up to you. If you switch to a low capacitance cable that's designed for instrument connection, you could be amazed, or not. And it may matter with some instruments and not others.
If I was selling cable, I'd say, sure, you need to replace that relatively high capacitance-per-foot star quad with something that will move the high-cut filter out to a higher frequency. But you won't know if it matters unless you try. Length matters, too. 10 feet of just about any cable won't hurt anything, but 25 feet or longer and you'll be more likely to hear a difference.
Mike wrote:
On the TRS end, connect the two blue wires to the tip, connect the
two white wires to the sleeve, On the T-S end, connect the two blue
wires to the tip of one plug and the two white wires to the tip of the
other plug. Connect the sleeve to the sleeve of one plug.
Mike, I think you meant to write *ring* and not *sleeve*....... On the
TRS end, connect the two blue wires to the tip, connect the two white
wires to the sleeve , On the T-S end, connect the two blue wires to
the tip of one plug and the two white wires to the tip of the other
plug. Connect the sleeve to the sleeve of one plug.
Try it like that. You'll have a bit of unshielded wire and no
sleeve connection for one of the TS plugs, but that input will get its
ground through the chassis as long as the other plug is plugged in. For
consistency's sake, you could run another piece of wire from the sleeve
of the "grounded" plug to the sleeve of the ungrounded plug, giving it a
path to the TRS plug's ground.
At least I think you meant ring and not sleave???
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