SMPS and grounding

[asdf1000]

On 20/09/2017 at 12:27 PM, JohnSwenson said:

You may ask "how effective IS this?"

 

Here are some graphs, the first is the leakage current of an SMPS, the second is with this adapter plugged in:

 

Hi John, do these leakage current levels with this adapter method, come down to linear PSU leakage current levels?

 

Just speaking in terms of leakage current levels, not DC voltage noise/ripple of course.

 

 

[asdf1000]

10 minutes ago, JohnSwenson said:

stay tuned!

Cheers John!

[asdf1000]

I've found grounding the 2 x SMPS's right before my  Hugo2 headphone setup has improved things. Grounding the router and powered USB hub and other things further upstream of the DAC have made less difference in my system.

 

The Hugo2 is powered by an iFi 5V at 2.5A (the Hugo2 needs >2.1A so I can't use an LPS-1 unfortunately, otherwise I would) with the iPower's DC plug now grounded with John's method. Except during really critical listening sessions I unplug the power supply completely. But 90% of the time, I prefer to keep the Hugo2 powered by the 5V iPower anyway. So a combination of the ~1uV 5V iPower and now lower leakage current makes for a better low cost PSU. 

 

The Hugo2's USB audio input is fed by an Iso Regen + LPS-1, with the latter's Mean Well's DC plug also now grounded with John's method.

 

So those 2 changes right before the Hugo2 DAC have really improved things more than grounding further upstream. More bass, more detail, less listening fatigue. Not earth shattering but noticeable improvements (for cheap too).

 

But I can tell John is so passionate about doing these the right way, so even if the further upstream grounding doesn't have as much as an audible improvement in my system (it MAY in others systems of course) I kind of want to do it right also, so I'll keep whatever I can grounded.

 

It's not that expensive to do. Thanks @JohnSwenson !

 

PS: can you share what this grounding method does with the iFi iPower's leakage current, which you said previously measured the worst of your tested SMPS's? And can you share if the number drops to the levels of typical linear PSU's?

 

Cheers

[asdf1000]

I wonder if it's to prevent the leakage currents from getting into other gear via another path, like neutral?

 

So even with the LPS-1, it shunts the Mean Well's leakage currents to ground, to prevent it from going through other loops/power supplies via other pathways? I guess the current takes the path of least resistance, which is the bare wire used with the SMPS grounding adapter, to the earthed plug? Or the iFi groundhog which does the same.

 

 

[asdf1000]

Hi @JohnSwenson

 

Earlier today, on the ultraRendu thread about grounding switches, you mentioned for the LPS-1 it's best to ground the LPS-1 output, not the Mean Well Energizer's 7.5Vdc output:

 

https://www.computeraudiophile.com/forums/topic/30376-a-novel-way-to-massively-improve-the-sq-of-computer-audio-streaming/?do=findComment&comment=730369

 

Is that the same if using and LPS-1 to power the ISO REGEN with isolation switched OFF? I should ground the LPS-1 OUTPUT - NOT the Mean Well Energizers 7.5Vdc output?

 

Cheers again

 

[asdf1000]

On 02/10/2017 at 11:11 AM, Superdad said:

On 02/10/2017 at 9:50 AM, agladstone said:

Also, if I followed this thread carefully enough, it seems like for my LPS-1 that powers my ISO Regen, I would want to have the ground wire going to the DC input of the ISO-Regen and NOT the DC input of the LPS-1, is this correct?

 

With the present topic, no, you would just ground the DC of the supply that you have feeding your LPS-1.

 

@JohnSwenson my confusion comes from the above quote - which says for this topic, you ground the LPS-1's Mean Well Energizer's DC plug, not the LPS-1's output DC plug

 

What's the reason the advice is the opposite for grounding ethernet switches.

 

Appreciated, as always

 

[asdf1000]

2 hours ago, rickca said:

@Superdad was talking about how to avoid dropouts when using galvanic isolation on the ISO REGEN.  That's a different goal than eliminating leakage currents which is what @JohnSwenson is addressing.  I think this is the source of the confusion.  Alex and John, please advise whether I've got this right.

 

When Alex said "With the present topic, no, you would just ground the DC of the supply that you have feeding your LPS-1" I don't think that relates to dropouts of the ISO REGEN - for dropouts, you need to ground the ISO REGEN'S USB output OR the ISO REGEN's input DC plug (LPS-1's DC plug output), since both do the same thing as both connected to the same ground of the ISO REGEN.

 

Agreed though, some clarification would be appreciated. Essentially:

 

1. When is it best to ground the LPS-1's DC plug output

 

2. When is it best to ground the LPS-1's Mean Well Energizer's DC plug output

 

 

[asdf1000]

9 minutes ago, rickca said:

Yes, you're right.  So now I share your confusion.

 

Ha! All good. I'm just glad I'm not the only one.

[asdf1000]

16 hours ago, Em2016 said:

 

When Alex said "With the present topic, no, you would just ground the DC of the supply that you have feeding your LPS-1" I don't think that relates to dropouts of the ISO REGEN - for dropouts, you need to ground the ISO REGEN'S USB output OR the ISO REGEN's input DC plug (LPS-1's DC plug output), since both do the same thing as both connected to the same ground of the ISO REGEN.

 

Agreed though, some clarification would be appreciated. Essentially:

 

1. When is it best to ground the LPS-1's DC plug output

 

2. When is it best to ground the LPS-1's Mean Well Energizer's DC plug output

 

 

 

Just for anyone interested in these questions and not following the other thread, John S has answered these 2 questions (and more) in this great post here:

 

 

 

[asdf1000]

2 hours ago, JohnSwenson said:

Theoretically you could do the same with USB, BUT USB is not just AC, it requires DC connectivity through the data pair, so a transformer will not work. This has made series blocking very difficult to deal with. There are a few solutions, but none of them block the high impedance components, so you still need to shunt the all the high impedance source before they get to the USB cable if you want to stop ALL the leakage from getting through to a DAC

 

Hi John, epic explanation.

 

Does this mean even the Intona fails to block high impedance components?

 

[asdf1000]

1 hour ago, JohnSwenson said:

Yes, that is correct.

 

John S.

 

Thanks John. I guess the challenge now is how to shunt the high impedance components from a computer's non-grounded SMPS, before it gets to the Intona/ISO REGEN etc.

 

Is the USB adapter that comes with the iFi Groundhog a good solution? Using that in the computer's USB port?

 

 

 

[asdf1000]

Just now, sandyk said:

 

Many Desktop PC's do have their SMPS grounded.

 

Laptops with 2-pin plugs don't though (like my Macbook).

 

Of course you can run off batteries but that can be impractical and add cycles to the battery.

 

[asdf1000]

Does anyone know if the GS105 V5 can be powered with 5Vdc? 

 

And does it take a 2.1mm or 2.5mm DC plug size?

 

[asdf1000]

33 minutes ago, Speed Racer said:

 

Why would you think it could? It requires 12VDC.....

 

It’s important (for me) to continue to learn new things:

 

 

 

[asdf1000]

8 hours ago, BigGuy said:

regardless, this all is a  "feel good" inexpensive tweak.

 

That's a nice way to put it! I said something similar earlier - it's more about doing things a little more correctly than expecting earth shaking improvements.

 

Of course if someone has a tremendous amount of leakage current coming through their DAC and this DAC is sensitive to this stuff, maybe the improvements could be significant for them.

 

As you say, it's an inexpensive tweak to implement anyway.

 

[asdf1000]

Hi @JohnSwenson

 

I know your research is still on-going on all this stuff and will take some amount of time.

 

But given the fact that FMC's aren't that much more expensive than the network switches you've recommended, I wonder why this isn't the preferred option for the most downstream ethernet point, given leakage currents would be fully blocked by the optical isolation?

 

We could still use your SMS grounding method on the FMC SMPS's.

 

Would be interested in your preliminary thoughts, if that's possible.

 

Cheers! Sean.

 

[asdf1000]

@austinpop, following on from our convo here: https://www.computeraudiophile.com/forums/topic/31728-ifi-audio-groundhog-the-official-thread-launched-5th-of-may-2017/?do=findComment&comment=739873

 

 

John S actually has the iFi Groundhog and recommended it, presumably after testing and measuring leakage with it.

 

So I don't think the 12-15 ohms impedance is an issue, no?

 

[asdf1000]

Hi John @JohnSwenson

 

Once you shunt the high impedance leakage to ground, using any of the methods you've suggested - where does this leakage go?

 

Obviously it goes to ground but what does it do?

 

Does this shunted leakage 'circulate' via the ground path of other GROUNDED SMPS's that happen to be plugged into the SAME powerstrip?

 

Or is it hard to say exactly what this shunted leakage does and where it goes?

 

I know you're flat out on new products and I do know you've stated that leakage loops form between power supplies so no need to revisit that (unless that's where my question leads to?).

 

The background to my question kind of relates to my current recently re-jigged setup.

 

At my office desk I have a Hugo2. This DAC has 2 separate micro USB ports, one for 5Vdc charging and one for USB audio input.

 

For the DAC's USB audio input I have the ISO REGEN + LPS-1 with grounded Mean Well - but I need to ground the ISO REGEN's USB output, using an Grounding ESD Plug and Silicone wire.

 

For the DAC's 5Vdc input, it's powered by a grounded iFi 5V iPower.

 

Sure the leakage loop from the computer is blocked by the ISO REGEN but I guess when I look at my setup I keep thinking that there's a leakage loop between the Ground ESD Plug and the iFi 5V iPower, through the DAC's groundplane...

 

So is all the leakage that's been blocked upstream of the ISO REGEN now travelling between the Grounding ESD plug and DAC's 5Vdc grounded iFi 5V iPower, through the DAC's groundplane?

 

Much appreciated, Sean.

 

 

 

[asdf1000]

47 minutes ago, jamesg11 said:

Apropos? -

https://www.computeraudiophile.com/forums/topic/35129-a-novel-way-to-massively-improve-the-sq-of-the-microrendu-ultrarendu/?page=18

 

 

Hi Jim, I had seen that. But that's about 'noise' going back into the mains line it seems, not leakage current specifically?

 

[asdf1000]

10 minutes ago, Cornan said:

What is more likely is that you add another path for leakage current to flow through

 

Thanks Cornan, I guess this line in particular answers my question.

 

ANY path that forms a loop (with the DAC being part of a loop) can create a path for the leakage through the DAC.

 

Even if it's just grounding wire with a grounding plug I guess. Which could be a problem for those of us that need to ground the output of the ISO REGEN, if the DAC has other grounding. Or even if it doesn't - since leakage currents don't just travel via ground.

 

So even if you block all the leakage coming into the USB DAC input, then it can find it's way into the DAC via the grounding wire path and through the DAC's SMPS (if it uses SMPS, per my original example/question).

 

I am trying to piece together bits and pieces to draw these conclusions but hopefully @JohnSwenson can correct me if I'm wrong.

 

 

[asdf1000]

 

29 minutes ago, One and a half said:

so I listened to CDs of the same music I've been playing from Jriver lately. Wow, where did the bass come from, and the depth. For a CD player, paths and power supplies are short and linear.

 

Your CD player isn't a normal one though Gary !  

 

That wonderful Playback Designs SACD transport/DAC is quite special

 

 

31 minutes ago, One and a half said:

For a computer playback system they are a dog's breakfast (all over the place), no wonder noise gets in via unshielded power cable, DC unshielded, SMPS, low cost high noise switching regulators, filters..

 

Too true.

[asdf1000]

Hi @JohnSwenson

 

If I have the following chain (everything plugged into one single simple powerstrip of course):

 

Netgear GS105 with grounded DC plug > ultraRendu + Uptone LPS-1 (non-grounded 7.5Vdc Mean Well) > iFi iDAC2 USB DAC (bus powered by the ultraRendu)

 

I guess (please correct me) the high impedance leakage has a path from the LPS-1's non-grounded Mean Well to the grounded GS105? This leakage path isn't through the DAC of course, it's through the ultraRendu.

 

Is that ok? Is it really just the DAC we are trying to protect from leakage coming in?

 

Or is it still best to ground the LPS-1's 7.5Vdc Mean Well, even in this setup above?

 

Or is grounding both the LPS-1's 7.5Vdc Mean Well and the Netgear GS105 supposed to achieve something different?

 

Cheers!

[asdf1000]

1 hour ago, JohnSwenson said:

The leakage from the un-grounded Mean Well may wind up going through something else, it depends where the DAC goes. If it has an on board headphone amp and you just use headphone, then the leakage can't get out of the DAC, if the DAC drives a preamp or power amp the leakage can go through the DAC to one of those, EVEN IF IT IS NOT GROUNDED. Leakage currents go through power supplies even if they just have two prong plugs.

 

The DAC is probably the most sensitive component to leakage current, but not the only one. A renderer such as the ultraRendu is still susceptible to leakage, so setting up a system which deliberately feeds leakage through it is probably not a good idea. I would at least ground the Mean Well. An LPS-1 after the grounded Mean Well or some other good linear PS is even better.

 

John S.

 

Cheers John.

 

The DAC is feeding dad’s 70’s Sansui integrated amp.

 

So then I assume it’s best (ideal) to ground BOTH the LPS-1’s Meanwell AND the GS105 which feeds the  ultrarendu?

 

No downsides to this double grounding ? Both are on the same powerstrip. RCA interconnects are your recommended Belden’s with the patented JSSG.

 

 

[asdf1000]

Hi @JohnSwenson

 

I understand there's a few recommended network switches that you've tested for grounding.

 

For someone looking to see if their current switch (or existing router with built in 5 port switch for example) will do, how do we do a continuity check with a grounded SMPS and the switch?

 

I assume it's the PCB ground plane we need to do a check on, not the metal case. Does this mean the switch NEEDS to be opened for a continuity test?

 

It's easy enough to do a continuity check with a computer or anything with a USB port (for example) by using the outer shell of a USB cable for example.

 

But I'm just trying to figure out how to do it with a switch.

 

Cheers!

 

[asdf1000]

4 minutes ago, JohnSwenson said:

Actually measuring a switch or router or whatever is not an easy task, it takes specialized test equipment and knowing what you are doing

 

Cheers John, all is clear.