Hello all.
I am planning on using an unbalanced 1/4” TRS output to send stereo line level to a balanced stereo amp with XLR inputs.
The cable will be Canare L-4E6S. In the middle of the cable I’d like to use a small box to do the actual splitting (i.e. 1 in, 2 out). Should this box be non-conductive, or metallic? If the latter, to which ground/shield should I bond it?
I am planning on using an unbalanced 1/4” TRS output to send stereo line level to a balanced stereo amp with XLR inputs.
The cable will be Canare L-4E6S. In the middle of the cable I’d like to use a small box to do the actual splitting (i.e. 1 in, 2 out). Should this box be non-conductive, or metallic? If the latter, to which ground/shield should I bond it?
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How long will the cable be? If it's quite long(10ft+) there should be a transformer isolator inline to eliminate any induced noise and this is then a convenient spot to do the unbalanced to balanced conversion, the ART DTI is good example of this device. Best practice is to place it near the source to make the unbalanced portions as short as possible but you can get away with almost any placement.
if you just do a cable split there is no advantage to the XLR side being balanced but a metal box should help make the shielding continuous which will minimize induced noise.
if you just do a cable split there is no advantage to the XLR side being balanced but a metal box should help make the shielding continuous which will minimize induced noise.
Transformers introduce a lot of distortion, better to just run two cables from the source (split at the source), to take advantage of the differential inputs. When you say balanced stereo amp you mean a single ended amp with differential input conversion, not a balanced differential amplifier? The latter expects balanced signals, not just differential.
If the source is low impedance no real need for a shielded box, capacitive coupling is much less for low impedance, and the split point is small in volume compared to the cable in its entirety - can't hurt to shield the split of course.
Connect each cables ground or shield to the box, so the cables post-split will have ground on the shield and on the cold signal wire(s). Do not connect cold signal to shield at the destination end though, or you'll inject all the shield current back into the circuit.
If you can fit all the split-point wiring into the 1/4" plug that would be great, but I think the cables are too bulky for that.
If the source is low impedance no real need for a shielded box, capacitive coupling is much less for low impedance, and the split point is small in volume compared to the cable in its entirety - can't hurt to shield the split of course.
Connect each cables ground or shield to the box, so the cables post-split will have ground on the shield and on the cold signal wire(s). Do not connect cold signal to shield at the destination end though, or you'll inject all the shield current back into the circuit.
If you can fit all the split-point wiring into the 1/4" plug that would be great, but I think the cables are too bulky for that.
Yes, you are correct, it would be a SE amp with differential input conversion (TPA3255EVM using NE5532s, I believe).
The source is a JDS Labs Atom Amp 2 (for reasons), rated at 0.7 ohm output impedance.
OK, just to make sure, all 3 cables will have their shield connected to the metallic box. I am aware not to connect pin 1 to pin 3 at the XLR inputs.
EDIT: Follow-up question. How bad would it be if this metallic box were to accidentally touch something else that was grounded? Say, another audio chassis, or a computer chassis, or something? Would it be worth it to sleeve it somehow, to avoid any conduction to other bodies/circuits?
The source is a JDS Labs Atom Amp 2 (for reasons), rated at 0.7 ohm output impedance.
OK, just to make sure, all 3 cables will have their shield connected to the metallic box. I am aware not to connect pin 1 to pin 3 at the XLR inputs.
EDIT: Follow-up question. How bad would it be if this metallic box were to accidentally touch something else that was grounded? Say, another audio chassis, or a computer chassis, or something? Would it be worth it to sleeve it somehow, to avoid any conduction to other bodies/circuits?
