SMPS and grounding

[barrows]

@JohnSwenson,  How much leakage current are we talking about here?  Suppose I have a SMPS rated at 40 µA  (yes micro) of leakage current, at this rate I would presume that I would not need to worry about it at all?  This SMPS made positive subjective improvement when used to power the router which connects directly to my Rendu(s) with the output floating, maybe just because of reduced leakage current (of course this is a high end SMPS with low output noise characteristics as well).

 

I have another SMPS (20W, 9V) rated for .78 mA leakage current, would that be enough to cause concern?  Maybe I'll build this one up into a Rendu supply, and apply a switch to ground (or not) the output for testing purposes...

[barrows]

12 minutes ago, Cornan said:

 

Like with ethernet cables USB cables clearly sounds best with a floating shield a la JSSG IMO. The problem occurs if the shield is connected to the plugs. 

I prefer using my cables without ferrite cores since they could dampen the sound. I choose to use JSSG, grounding, starquads and cable distance instead.

As with most things, this will be system dependent.  Where the USB shell is terminated, and where the USB ground is terminated will matter, as I would expect so will whether or not USB in the receiver is isolated.

[barrows]

@Cornan, I am sure this is covered in the crazy tweak thread, but I am curious how you "isolate" network/computer gear grounds from audio system grounds?  All grounds in your home (should) be connected to single point ground reference.  Or have you placed a separate ground rod rod into the earth, actually having two ground references for your home?  I know some actually do place a separate ground rod for the audio system, but I am pretty sure this violates the NEC in the US for domestic homes.

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55 minutes ago, agladstone said:

My thoughts exactly! I have all these nice Ghent cables I’ve ordered with the Canare 4s6 and Oyiade plugs and now I have a bunch of cheap screw on DC plugs (female and male) that I’ve wired and screwed together myself and I keep thinking I’m negating the benefits of the oyiade plugs 

I have one of the Oiyade DC plugs here...  While it certainly is nicely made, I do not see anything about it which would give it an actual performance advantage over a good Switchcraft part.  Sure it has gold plate (almost certainly thin gold flash over a nickel base) but at DC the current is going to be traveling through the base metal anyway.  And the base metal is brass or bronze and not copper.

I have never been able to find any DC barrel plugs made with copper, too bad, as the part seems like it could easily be made from copper...

[barrows]

Remember not to simplify things folks, leakage current is not the only thing which matters, differential noise is still important, it is not just about leakage current.

[barrows]

Or, just a DAC with good, well done, linear power supplies.

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37 minutes ago, Takacid said:

Hi John, very interesting. I'm using Synergistic Research's Grounding Block. http://www.synergisticresearch.com/isolation/ground-isolation/grounding-block/

Instead of the 3pin AC power plug above, could I just have the green wire connect to the Grounding Block? Thanks,

Is the Synergistic Grounding block actually grounded to AC ground?  I would confirm that it is, and then use it.  if it provides a "virtual" ground as some of these audiophile devices do., then I would not use it for this purpose.

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3 hours ago, lvc10000 said:

And the more cables added, the results seems to add-up further in the same direction.

It is seductive with one cable in the loop in the sense that it brings out better focus to the medium and voices for example and fleshes out a bit further/more. However as counter example, a cymbal goes/tones down a notch, or for example a piano's wooden resonances information are reduced/hidden. Tough call. 

 

And there's the rub.  Using subjective analysis alone in these kind of circumstances can be difficult.  What is perceived as a reduction in high frequency energy, often is a reduction in distortion, and hence, more accurate.  I have run into this type of "problem" many, many times in my experience doing customer service and trying to help customers/dealers achieve the best sound.  One might change something in their system which we know is an improvement, from a technical perspective (measured lower distortion/noise), but then they find the system perhaps lacking in "air".  The reality is that the "air" they heard before was really an artifact, and not accurate.

If we rely only, and completely on subjective listening tests, without also applying a technical understanding, and measurements where possible, we can often go down "wrong" roads, and get detoured away from accurate sound in playback.

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13 minutes ago, Cornan said:

 

I tend to agree with most of your posts, but not at all with this perticular one I’m afraid! 

The sence of air is not an artifact. IME it is actually a confirmation that you are heading in the right direction but need to optimize something in the chain to get closer to the presence, 3D & 4D experience. Likely the choise of cable material, capacitors or voltage regulators IMO.

Perhaps I did not explain my point adequately.  I did not mean to suggest that the idea of "air" is ALWAYS an artifact.  Only that when distortion is reduced, sometimes, some of the "air" apparent in a system will be reduced, and this could be perceived as a "problem" when it is actually not: if the reduction in distortion results in a loss of desirable "air", the problem is elsewhere in the system, and not in the change which resulted in the loss of some "air".  So, by reducing the distortion, one has discovered an actual (new, because it was previously hidden) problem in the system which needs to be addressed.

 

The point I am trying to make is that often changes which are actually in fact improvements, can be perceived as negative, when really the improvement is just revealing  a new problem to be addressed.

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9 minutes ago, JohnSwenson said:

Yes that completely destroys the optical isolation. The shunt is there to shunt high impedance leakage from SMPS over Ethernet cable. So in this case you would never need it on the TP-Link, since the optical prevents it from going downstream. You only need it on the OM IF it is powered from an SMPS.

 

John S.

What he said...  I power my oMdeluxe with a high performance linear power supply, with the output floating.  This is on the "dirty" side (server, router, switch, etc) of my components in my workroom.  By powering the (critical) sending oMdeluxe by a floating linear supply, it is also well isolated from the noise produced on the power line by the computer gears.  The the optical fiber runs to the audio system (Signature Rendu SEoptical).  I also use a noise reducing Sablon Ethernet cable for the critical copper run to the oMdeluxe to keep noise coming in on the cable down as much as possible.  Note that the Sablon Ethernet cables, despite having expensive Telegartner connectors, do not have their shields connected to the connector bodies, so they do not create a ground connection between Ethernet points (unlike many other cables made with metal body connectors).