AES promote a connect 0V to chassis/ground/earth method.
Google: AES, Whitlock, Ott, Muncy and Ground. Hopefully it will get you on the path to enlightenment. 🙂
Google: AES, Whitlock, Ott, Muncy and Ground. Hopefully it will get you on the path to enlightenment. 🙂
- All grounds do not go directly to the chassis.
- Absolutely avoid having any ground conductor handling both signal and power returns.
- Avoid multiple ground paths for the signal (ground loops).
- Use only one end of the shield inside equipment.
- Do not connect the chassis directly to the signal or power supply grounds. Isolate it with a type X2 capacitor and parallel resistor.
I presume that you mean to safety/earth ground? If you do, that's true, so long as no exposed conductive elements of the internal circuit are accessible externally for shock hazard reasons. Which, I believe, is the point AndrewT has been making.
Commercial audio equipment sometimes has signal ground (0 volt node, as you call it) isolated from safety ground via some device, such as a diode bridge, or a varistor. Such devices break or limit power mains induced ground loop noise current via that equipment's power plug, while still ensuring that safety ground and signal ground remain safely close in voltage potential. An internal fault energizing the enclosure via the ground isolated internal circuit will still trip that equipment's internal protection breaker.
ok Ken can you explain why "ensuring that safety ground and signal ground remain safely close in voltage potential" is correct or even required? signal ground and safety ground can be at different potentials without problems.
Last edited:
I will let you answer that for me. Would a shock hazard exist on the exposed outer ring (signal ground) of an RCA jack should the preamplifier circuit driving that jack experience an internal fault that coupled 120V (with respect to safety ground) on to that circuit's signal ground?
not for long if the safety/earth ground is functioning.
and if the rca was isolated from the case there's less chance of that condition existing.
and if the rca was isolated from the case there's less chance of that condition existing.
Yes, it is. Which is why audio system hum problems are not uncommon. However, not earthing exposed connectors is a recipe for death by electrocution. National electrical codes are not concerned with audio hum problems, they are concerned with safety.
You're making my point. If the powered circuit is isolated from safety ground then the safety ground offers no shock hazard protection.
Rather than reducing a shock hazard, isolating an exposed connector from an safety earth'd chassis creates a shock hazard if there is no other tie between safety/earth ground and the signal ground.
All voltages are differential.
'0v' is one convention for the low side.
It is frequently confused with 'earthing', 'grounding' ; and some nebulous idea of 'an infinite sink for all currents'; all are misplaced.
All voltages are differential.
'0v' is one convention for the low side.
It is frequently confused with 'earthing', 'grounding' ; and some nebulous idea of 'an infinite sink for all currents'; all are misplaced.
All voltages are differential.
i whole heartedly agree that electrical safety is paramount.
so perhaps a new standard in connectors in which the signal common/ground is not exposed or touchable making it complient with code should be explored. or perhaps all interconnects should contain repeat coils so that we can have a better chance at peace and quiet (in our systems)
still don't know, or thus far no one has adequately addressed my original query as to why the 0 volt node of a supply should see safety earth. why is leaving this node floating not acceptable?
so perhaps a new standard in connectors in which the signal common/ground is not exposed or touchable making it complient with code should be explored. or perhaps all interconnects should contain repeat coils so that we can have a better chance at peace and quiet (in our systems)
still don't know, or thus far no one has adequately addressed my original query as to why the 0 volt node of a supply should see safety earth. why is leaving this node floating not acceptable?
An ground loop noise canceling audio signal interconnection standard has long existed. XLR connectors over a 3-conductor balanced impedance interface.
Yes, we have. Several times. Perhaps, you are not able to comprehend the technical explanation. Or, maybe, you're simply too stubborn to acknowledge it.
if a fault where to put a lethal potential on an isolated connectors ground wouldn't that fault not also cause a supply line fuse or protection to trip/activate(?) and in the event that the fault not be sufficient to blow fuses or trip protection would the circuit still operate correctly...
and when it comes to balanced connections the proliferation of semi pro gear with "bad ground practices built in" and some members of this forum falsely expounding that "all" connections made using XLR's must have pin 1 connected to the safety earth is not entirely correct
in microphone circuits indeed pin 1 should be at ground/earth ac mains ground for safety.
but for interconnects linking pin 1 to both signal and safety grounds is a garrantied ground loop.
in microphone circuits indeed pin 1 should be at ground/earth ac mains ground for safety.
but for interconnects linking pin 1 to both signal and safety grounds is a garrantied ground loop.
What some would term, insults and derision, others would term, evident truth. No matter, I won't waste anymore of my time and effort. Let's leave it at that.
so nothing to offer nor can you point to where explanation was given, thanks Mr Newton i'll take that as you don't know.
I started out drawing schematics verbatim and was advised to learn to use the earth symbol for clarity.
- Status
- Not open for further replies.