Hi Guys,
I have just wanted to ask you - while browsing through all the diy schematics and even the schematics of off-the-shelf amplifiers.
Have you ever encountered the part regarding grounding the ground lug of the 4pin XLRs? Does it ever connect to chassis ground?
I have just wanted to ask you - while browsing through all the diy schematics and even the schematics of off-the-shelf amplifiers.
Have you ever encountered the part regarding grounding the ground lug of the 4pin XLRs? Does it ever connect to chassis ground?
I would expect the shell of the XLR connector to be floating on most (all?) headphones. I see no harm in grounding it.
As far as connecting the headphone signal ground to the chassis goes, I'd leave that up to the circuit designer.
Tom
As far as connecting the headphone signal ground to the chassis goes, I'd leave that up to the circuit designer.
Tom
Scott, yes, exactly, shell, or as Neutrik likes to state "separate ground contact to mating connector shell and front panel". Basically the very additional pin alongside with main 4 pins.
I was actually surprised, Tom, we see the constant push on manufacturers and designers to always improve the noise performance of audio devices, yet something like this stays overlooked. Yes, the HP cables tend to be shorter and yes, HP cable will not tend to be boundled with other interconnect, power and speaker cables, but even then I would have thought this will be considered in the design stage.
So then, if I may to extend the original question - with TRS connector as a HP-Out, is the sleeve used exclusively to rectify it to the signal ground?
I was actually surprised, Tom, we see the constant push on manufacturers and designers to always improve the noise performance of audio devices, yet something like this stays overlooked. Yes, the HP cables tend to be shorter and yes, HP cable will not tend to be boundled with other interconnect, power and speaker cables, but even then I would have thought this will be considered in the design stage.
So then, if I may to extend the original question - with TRS connector as a HP-Out, is the sleeve used exclusively to rectify it to the signal ground?
For fully balanced operation, the shield should connect to chassis ground at the point of entry. This is also true for unbalanced operation when a third shield conductor is available in which you connect the shield to chassis ground at the point of entry. However, this is only valid when 2-conductor shielded cable is used.
However, the manufacturer choice of signal-grounding or chassis-grounding balanced shields does not affect the cable re-wiring and other technical support solutions normally recommended when interconnection of balanced and unbalanced equipment is needed.
Therefore, you need not hesitate in addressing your "4pin XLR problems". You can still get a balanced interconnection by providing chassis ground on balanced shields.
However, the manufacturer choice of signal-grounding or chassis-grounding balanced shields does not affect the cable re-wiring and other technical support solutions normally recommended when interconnection of balanced and unbalanced equipment is needed.
Therefore, you need not hesitate in addressing your "4pin XLR problems". You can still get a balanced interconnection by providing chassis ground on balanced shields.
However you do not want to have shielded HP cable for balanced at all, if the very XLR output connector is not connected to the chassis throughout ground lug, therefore just floating
If you do it...let's say you choose to use some of the popular star quad cable and you connect or even use that very cable, you would not just not protect it against any stray interference, you would add to any stray interference pick-up (as there would be no path to the ground), would you not?
If you do it...let's say you choose to use some of the popular star quad cable and you connect or even use that very cable, you would not just not protect it against any stray interference, you would add to any stray interference pick-up (as there would be no path to the ground), would you not?
Please define what you mean by "ground". When the shield of a balanced cable is connected to the chassis it effectively becomes an extension of the shield provided by the chassis
Yes, of course, I am reffering to chassis ground in general, only my last question from yesterday was about how it then works with unbalanced, TRS jack (if the sleeve is used immediately to rectify the "return" to signal ground) concerned the signal ground.
And yes, I hoped (long ago) it works like that, as you describe, Scott in the last sentence of yours. Tt is indeed logical to have the HP output grounded to chassis ground throghout the ground lug of the 4pin XLR and therefore use the easy to work with star quad cable to provide all - L+/-, R+/- and shield. Even tho both, the output and headphones together form quite a low impedance interface, compared to the speakers the headphones work with just a fraction of the power what speakers use and transmit, so it is (in my opinion) susceptible to som kind of a stray interference.
And yes, I hoped (long ago) it works like that, as you describe, Scott in the last sentence of yours. Tt is indeed logical to have the HP output grounded to chassis ground throghout the ground lug of the 4pin XLR and therefore use the easy to work with star quad cable to provide all - L+/-, R+/- and shield. Even tho both, the output and headphones together form quite a low impedance interface, compared to the speakers the headphones work with just a fraction of the power what speakers use and transmit, so it is (in my opinion) susceptible to som kind of a stray interference.
No, it also acts as a screen if connected to the screen of the cable
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Now I have actually made a mistake. Yes, I should have written and asked if the TRS and its sleeve is usually rectified to the very ground (chassis ground) or is it like with XLRs, where the ground lug is just floating (NC).
It's primary function is as a common L+R signal return, but could also act as screen if required and a screened cable is used. If a 4 core screened cable is used with 4 pin XLR it would be beneficial to connect screen to chassis
Definitely, it would be beneficial, but going down the "rely on the manufacturers' practice to ground the lugs (or a sleeve of TRS) to chassis ground" is a tricky one too, is it not? Having shielded HP cable is "no effect on noise performance" at best.
I reckon the very best way (even though not my favourite one) is to stick with unshielded headphone cables (unfortunately it is a good message to all those unobtanium-styled copper/silver/plutonium made twisted, french braided yet many times really nice looking cables out there).
I reckon the very best way (even though not my favourite one) is to stick with unshielded headphone cables (unfortunately it is a good message to all those unobtanium-styled copper/silver/plutonium made twisted, french braided yet many times really nice looking cables out there).
I think you'll have to experiment, I have some Grado headphones with an unscreened 4 core cable that worked fine until I wanted to extend it, then the problems started. In the end I used a couple of coaxial cables to make an extension which cured the problem. The screen was not connected to chassis, merely the speaker return
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