I don't have any gear with a filter integrated into the IEC receptacle. I'm not sure Ive ever seen any home AV kit that has.
me neither, those receptacles are relatively expensive and might be overkill when the goal is to comply to conducted emission/immunity. Chances are some simple filter components inside the gear on a PCB are sufficient and better suited for the job at hand (which usually is emission, not immunity).
There might be some gear that uses those and vaguely remember seeing one in an expensive amp design but is rare indeed.
What is more common is an inlet with an integrated fuse.
They receptacles with integrated filter (properly screened all the way to the output) will very likely outperform the filters found on any SMPS.
Rather, I would wager that it generally involves a effects of leakage currents of one or either device causing common mode noise..
agreed.
Safety ground does not equal ground.
I would postulate that any piece of equipment which may suffer susceptibility issues with common mode noises which fall under this level *IS* an improperly engineered piece of equipment.
Then almost all (home) audio equipment is improperly engineered.
Frankly I am amazed how often connected gear using RCA interconnects works as problem free (no audible noise(s)) as they do in practice.
Another thing is that only the people that have 'weird' issues with gear ask for advice on ASR about these issues.
Mostly the problem is solved by USB isolators or some grounding or connection errors.
Hardly ever by buying other gear (although this also can help) or modifications to existing equipment even is that is 'improperly engineered'.
Not always, class II by definition is not grounded (to safety ground) and also not needed from a safety standpoint. Ground lift could help or make things worse depending on how and where leakage currents travel.
I agree on 'isolation'. However, the fault may not be due to a 'lack of isolation'.
In the vast majority of connected DAC issues they usually are. Of course there could also be an issue caused between mains fed DAC and mains fed amp for instance which won't be solved with galvanic separation between DAC and digital source.
This too will likely be an interconnection issue that might not be happening with the same gear used by someone else.
Its 2025, any USB DAC which is not comptable with common computer hardware is just poorly designed. IMHO.
It could be a connecting issue or some computer hardware/firmware/software that is at 'fault' as well, doesn't need to be the DAC itself which might or might not fully comply to the different USB standards the DAC might be connected to. The choice of DAC could solve that though. For instance a DAC that requires USB3 and draws a higher current than some laptop/phone/tablet or USB socket (USB splitter in between for instance) draws could be a reason for a DAC that is USB3 compliant not to work with some USB2 'compliant' devices.
Weird, I would have hoped the collective expectation of audio equipment buyers would be that the equipment they purchase would be compatable with the other equipment when featuring the same type of interface. e.g. USB to USB, RCA to RCA, XLR to XLR, toslink to tosklink.
Usually they are problem free (surprisingly)
With RCA, however, there are no standards and even toslink to toslink not always works above certain bitrates even if they do on other systems. For instance the LED in the transmitter may well have degraded in power output or there is something wrong with the POF cable or production tolerances (or changes in receiver manufacturer) may be the limiting factor.
USB to USB also isn't always fully compatible.
People expect that... sure. Practice often thinks otherwise.
I seriously wonder how many people have brought products to 'fix' preexisting problems in equipment which ought not to have it?
Yep, that will often be the case. Mostly based on reviews or well intended recommendations.
I would even go further and say how many people have bought certain products simply to prevent 'gremlins' to occur which were not needed in the first place.
That's the price one pays for not knowing. I reckon even most engineers do not know what is needed and what not.
I mean... not every one has a meter and would travel with the required type of meter(s) to debug audio issues and know what and how to debug.
EMC is quite tricky, sometimes even for EMC engineers that travel with a bunch of filters, ferrites, copper tape and whatnot.
Usually it is just leakage currents and the usual bag of EMC tricks might not solve anything.
Might I point out that this is a new thread?
Yep, but we all know where this thread is a spin-off from given the examples you gave.
Perhaps start a thread named 'what about leakage currents' for instance. And preferably offer possible solutions, measurements showing the issue etc. That helps people more than just blaming audio measurements missing these issues and desiring audio companies to 'design keeping all possible mismatches and problems in mind'.
Good engineers trouble shoot and offer solutions to problems. Not all gear is well designed to operate on all conditions that may or may not have been tested in practice nor rule out possible incorrect connections in the literally infinite possibilities of connections between gear.
The name of the thread title needs some clarification as well.
Would gear that performs the same (in audio quality) but has added some 'audible gremlin' (so severe enough to reach audible levels) still be audible transparent (as in performance) ?
Who determines when sound quality is found to be degraded by 'something' and how is that determined ?
I mean people hear differences when they wrap spiralit around the main water piping or connect a box with sand to something and hear differences that are so obvious that an AB is not even needed. Do those individuals qualify ? Even when they reduced some common mode current that does not even cause audible issues.
This too is an aspect of the thread title that can be discussed.
The same issue that causes some 'disturbance' of the audio signal may or may not reach audible levels (yet be present) and not everyone is equally bothered by an issue that potentially could be solved but requires effort and investments.
