Jump to content
IGNORED

SMPS and grounding


Recommended Posts

4 minutes ago, austinpop said:

However, that 15 ohm series resistance still bothers me. I'm hoping someone can validate that on their Groundhog, and explain why it's preferred to a straight wire (no resistance) like in John's gizmos.

 

Perhaps the resistance value is low enough to completely remove the high impedance sourced residual noise as measured from a typical SMPS, but high enough to reduce the possibility of inadvertent earth loops causing very low level hum where you may need to use 2 different mains outlets ?

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

Link to comment
2 minutes ago, sandyk said:

 

Perhaps the resistance value is low enough to completely remove the high impedance sourced residual noise as measured from a typical SMPS, but high enough to reduce the possibility of inadvertent earth loops causing very low level hum where you may need to use 2 different mains outlets ?

 

That's certainly plausible, and did occur to me too.

 

But is it preferred?

Link to comment
11 minutes ago, austinpop said:

That's certainly plausible, and did occur to me too.

 

But is it preferred?

 

 Good question.

I doubt that you would be able to measure or hear any difference between both methods.

 It always worries me a little about directly grounding the 0 volts rail of SMPS powered devices that were not designed to do this. Way back in 2006,  Silicon Chip magazine used a 22nF 275VAC X2 capacitor to mains earth instead, to help overcome this problem. ("Tingle Terminator") They connected a 100 ohm resistor across it for measurement purposes. However, despite my concerns, I did connect a direct earth to the 0 volts of my STB which has a Coax SPDIF connection into my DAC with improved results.

It was easier to implement.

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

Link to comment
29 minutes ago, austinpop said:

 

Greg, 

 

Have you tried grounding each of these zones? That's the path I'm on.

Rajiv,

 

I'm trying some different combinations. So far I've gotten better results grounding the isolator output ->DAC->TVC input AND amp->speaker zones. I have the RPi->Isolator input zone grounded, but need to go back and listen with/without.

 

I haven't grounded any of the other zones as yet.

 

ALL of the power supplies on the gear through the DAC are linear supplies, so no high-impedance leakage worries there. AND there are currently 5 LPS-1s in the setup... on the switch (a ZyTEL recommended by my UK friend Dave Bruce, which so far bests one of John's originally recommended Cisco SG100D-08 switches and the Netgear GS605AV switch I originally used, though I need to re-test both powered by an LPS-1), 1 each on the DAC digital and analog supplies, 1 on the RPi isolator board, and 1 on the Kali I2S reclocker.

 

Lots more experimentation to do here. BUT a significant upgrade I recently did was modifying the 5V Jameco Linear Regulated Adapters I use to power the FMCs (the upstream one directly, the downstream one via a TeckNet 5V USB charging battery that is being charged by the Jameco). I replaced the diodes with some good Schottky diodes, added John Swenson's transformer ringing snubber, increased the size of the raw DC and post regulator capacitors, and added an AC filter cap. AND also added a C-L filter (built in-between an AC plug and socket) that provided the same level of filtering I used in my DIY 4-LPS-1 energizing supplies (and BTW, all of the other computer & networking linear supplies in my setups).

 

I was inspired to do this by John's comments that the Jameco's have very low low-impedance leakage here:

 

On 9/14/2017 at 12:58 AM, JohnSwenson said:

I have been doing a bunch of leakage tests on a bunch of power supplies (what I had on hand). I have tested both the Jameco and the iPower, the Jameco has one of the lowest leakage tested and the iPower had the highest, about a million to one difference, that might have had something to do with your observations!

 

John S.

 

I could of course try to make them even better with better regulators, but my main rationale was to make them quieter on my AC lines, not make them better on the output side. Both seem to be accomplished based on what I'm hearing.

 

I'll do a blog post describing the mods at some point when I get some time.

 

Later!

 

Greg in Mississippi

 

P.S. Some may question the wisdom of modifying a roughly $10 adapter. BUT for about 2x the price in good parts & a little time (I did 4 of them on Sunday in about 5 hours), they make nice and easy to site units. The modification is not DIY beginner-level because of the effort and care needed to open the cases, remove the existing parts and position the now slightly larger parts so that you can re-close the cases, but someone who's done a little DIY and solder reasonably well could do them.  AND the sonic improvement over the stock units was significant, even though they were only powering FMCs.

 

P.P.S. I do plan some switch & FMC mods starting with replacing the switching DC-DC converters with good linear regulators. I'll try replacing the regs in the Jameco adapters when I do that work. I'd been considering this for awhile, but Fob69's posts here have revived my interest:

 

13 hours ago, fob69 said:

Hi

 

I just did it.

 

First, i took them away 6 monthes ago and replace them with an etalon isolator with a huge benefit, and i did add too a long ethernet distance between my switch and my etalon isolator (15m cat6 grounded only on switch side).

 

15 days ago i did change my internet box on my ethernet network and plug new equipments. I had to admit that even with the etalon isolator and the long ethernet wire, my new network config had downgrade image and timbres. It confirg to my the huge SQ impact of the noise coming from the network equipments (even with galvanic isolations).

 

I was about to buy linear supply for my new internet box, fiber modem, NAS ...  But before i did try to replug the MC110Cs btween my etalon filter and switch, on switch side.

 

I did see a good improvement especialy on the image but there was still some network impact on trebles as is was 6 monthes ago when i removed the MFCs (due to the 348kz signal of the PWM component).

 

 Then, considering again the PCB, i found a FAST, CHEAP way to bypass the PWM schitching supply in the MFC : i did unsold the "+" leg of the female jack plug of the pcb, an link it with to basic 2X 1A diods in serial to the PV3V3 hole close to the green electro condo.

Supplied by a standard 5V linear supply, the to diods downgrade the voltage to around 3,5 V just before the regulator, and the switching PWM component is short cutted.

 

This is the best 1$ upgrade ever.

 

All my network noise is now invisible from my player with the fiber bridge, and i bypass the switching power that is the main problem with the MFC.

 

The image ans definition is incredible.

 

I will post a photo this evening.

 

B.

Everything Matters!

2 systems... Well-Tempered Refs->ET-2.5->DIY or Lounge LCR MkII phono stages

Standalone digital Sony HAP Z1-ES or SDTrans384/Soekris DAM DAC

Networked digital Zotac PI320-W2 LMS Server -> EtherRegen -> USBBridge Sig -> Katana / Ian GB / Soerkis / Buffalo-IIIPro DACs

Passive S&B TX102 TVC or ladder attenuators -> BHK-250 -> Eminent Tech LFT-VIII / IV / VI

ALL gear modified / DIY'd; cables MIT;  all supplies DIY’d or LPS-1.2s w/HUGE Ultracaps; Audio gear on DIY AC filters + PS Aud P15s; misc gear on separate AC w/filters

Link to comment
7 hours ago, Superdad said:

 

 

John is getting tired of repeating himself (and he happens to be working simultaneously on tight deadline projects for both Sonore and UpTone this week), so allow me to explain and illustrate again:

 

For any SMPS you might have that is rated with leakage of 40µA--aside from that not specifying frequency--that rating absolutely is of the low-impedance leakage, not the high-impedance stuff that John is measuring.  All the "medical" SMPS units available--including the cheap ones--have leakage ratings of 50µA or less.  [75µA is the requirement for "medical" units as they are concerned with "touch-current" for human attached equipment, whereas standard "industrial" units may have leakage ratings about 10x that--0.75mA.]

 

But as John explained [in several of his very long posts on the subject in this thread], and as I illustrated with some of his measurement graphs, the high-impedance leakage is very much a separate component--one that can sail right on through and even show up in the single-ended output of DACs.  As also explained, it is relatively easy to shunt the high-impedance leakage [back to ground] so that it is not a bother.

 

 

So that 0.78mA leakage-rated SMPS you have is likely just like the Mean Wells we have been including (0.75mA)--but of course that is just the low impedance leakage.  And there is tons of it--from below 100Hz well into the MHz range:

lkdetect_MWnew_1Mhz_30k.thumb.gif.f23c0fcaf8091c91311fc032dfdeec37.gif

 

Nothing can block that (except an LPS-1 which just uses such as a charger).

 

And just to show what a "low leakage" (0.75µA) medical SMPS looks like (this graph is the low frequency range; we have other bandwidths):

lkdetect_MW32m_1khz_30k.thumb.gif.39865f35e596d8b676d2e697994c1f99.gif

 

And again from before, the results of shunting the DC zero-volt output ("ground") to AC ground, which shows the residual low-impedance leakage (over the same bandwidth; there is still a lot of leakage at high frequencies):

MW40_1khz_internalgnd_0929.thumb.gif.b817fde3e19880489264d1be56656156.gif

 

And finally, the leakage from an LPS-1 "energized"/charged from the same unit:

MW40_1khz_internalgnd_lps1_0929.thumb.gif.853e1d745e5c4146bba97e62ad5b1827.gif

 

Of course none of this has anything to do with power supply output noise, output impedance, or other PS performance factors.  But it (as well as measures taken by John, Jesus, and Amir at the output of an unbalanced DAC) illustrate how pernicious this high-impedance leakage can be.  And as people who are experimenting in their own systems are discovering (both with Ethernet switches, rendering endpoints, and other gear), getting rid of it is worthwhile sonically.

 

Most people have always assumed that--apart from their output not being particularly low-noise--that SMPS were bad because of what they kick back into the AC mains.  I have always maintained that that aspect is really not the issue--since the certification restrictions on this things require the emissions into the wall to be spread-spectrum and very low level--there really is more other noise crap in your wall than what a single unit adds.  Since the start we have said that leakage is the real evil--and the low-impedance stuff is just as bad and needs to be blocked.  But the events and tests of the past months have lead John to discover the high-impedance leakage component--which is much easier to get rid of.  We really have never seen anyone else discussing or addressing this.

 

Ciao,

--Alex C.

 

 

Alex, I can easily measure the power supply noise at the analog output of a DAC with various power supplies. I can also see how shunting the negative terminal on the output of the SMPS cleans this up. What I have yet to see is the infamous "high impedance" noise. While it may be present and may affect the DAC somehow it seems that it's importance is minuscule (being so hard to measure and all) in comparison to plan old AC noise. Anyway, I'm sure Johns research will clear all this up.

Link to comment
11 minutes ago, vortecjr said:

Alex, I can easily measure the power supply noise at the analog output of a DAC with various power supplies. I can also see how shunting the negative terminal on the output of the SMPS cleans this up. What I have yet to see is the infamous "high impedance" noise. While it may be present and may affect the DAC somehow it seems that it's importance is minuscule (being so hard to measure and all) in comparison to plan old AC noise. Anyway, I'm sure Johns research will clear all this up.

 

Yet you ARE seeing it!  The improvement that you see in when you compare the output (from your single-ended DAC) with a given supply shunted and not IS THE REMOVAL OF THE HIGH IMPEDANCE LEAKAGE.

Link to comment
8 minutes ago, Superdad said:

What I have yet to see is the infamous "high impedance" noise.

 

 Hi Jesus

 With devices such as DVD players, STBs etc.,  all you need to do is check the A.C. voltage between the case/ 0 volts line and Mains Earth with a DMM.

This high impedance noise can  read as high as half the actual A.C. mains voltage.

It is mainly due to the obligatory low value, high voltage capacitor between the Primary and Secondary sides of cheaper SMPS

as used in many consumer items in order to meet FCC requirements.

 

Regards

Alex K.

DVD Players p.13.jpg

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

Link to comment

A bit confused about these Groundhog devices. Would they work, or are they needed, on something like my Naim DAC V1, which is obviously grounded via the power cable to a dedicated 20amp Porter Port socket? It has RCA outs (I use the DIN out to a Naim amp) and RCA SPDIF in (digital inputs only). It also has the option for chassis ground or floating - I use chassis. Would the GH just create a ground loop? Would rather not go there unless it would mean a big jump in sq (and not blowing up my DAC) as it would mean introducing a power strip in order to plug in the ground (the two outlet socket is used by the DAC and amp). 

SERVER CLOSET (in office directly below living room stereo):NUC 7i5BNH with Roon ROCK (ZeroZone 12V on the NUC)>Cisco 2690L-16PS switch>Sonore opticalModule (Uptone LPS 1.2)>

LIVING ROOM: Sonore opticalRendu Roon version (Sonore Power Supply)> Shunyata Venom USB>Naim DAC V1>Witchhat DIN>Naim NAP 160 Bolt Down>Chord Rumor 2>Audio Physic Compact Classics. OFFICE: opticalModule> Sonore microRendu 1.4> Matrix Mini-i Pro 3> Naim NAP 110>NACA5>KEF Ls50's. BJC 6a and Ghent Catsnake 6a JSSG ethernet; AC cables: Shunyata Venom NR V-10; Audience Forte F3; Ice Age copper/copper; Sean Jacobs CHC PowerBlack, Moon Audio DIN>RCA, USB A>C. Isolation: Herbie's Audio Lab. 

Link to comment

Your Dac

4 hours ago, charlesphoto said:

A bit confused about these Groundhog devices. Would they work, or are they needed, on something like my Naim DAC V1, which is obviously grounded via the power cable to a dedicated 20amp Porter Port socket? It has RCA outs (I use the DIN out to a Naim amp) and RCA SPDIF in (digital inputs only). It also has the option for chassis ground or floating - I use chassis. Would the GH just create a ground loop? Would rather not go there unless it would mean a big jump in sq (and not blowing up my DAC) as it would mean introducing a power strip in order to plug in the ground (the two outlet socket is used by the DAC and amp). 

This grounding is only for SMPS. If your DAC has an SMPS then some form of grounding will probably be good. Since it supports 120 or 240 and there is no voltage selector switch it is PRPOBABLY an SMPS inside, so grounding is probably a good thing.

 

Interestingly there is a ground select switch on the back, setting this to "chassis" will probably do the appropriate grounding without having to worry about anything else. Try the ground switch both ways and see what sounds the best. No need to do any other external grounding.

 

John S.

Link to comment
5 minutes ago, JohnSwenson said:

Your Dac

This grounding is only for SMPS. If your DAC has an SMPS then some form of grounding will probably be good. Since it supports 120 or 240 and there is no voltage selector switch it is PRPOBABLY an SMPS inside, so grounding is probably a good thing.

 

Interestingly there is a ground select switch on the back, setting this to "chassis" will probably do the appropriate grounding without having to worry about anything else. Try the ground switch both ways and see what sounds the best. No need to do any other external grounding.

 

John S.

Naim gear is always star grounded through the DIN connectors, hence the weird cable routing through preamps . . . etc.

Pareto Audio aka nuckleheadaudio

Link to comment

Thanks John for taking the time to answer. Sounds like that would be a ground too far but I thought it wouldn’t hurt to ask. I’m so incredibly appreciative of the ground shunt trick you’ve shared with us. All the best from Seattle. CP

SERVER CLOSET (in office directly below living room stereo):NUC 7i5BNH with Roon ROCK (ZeroZone 12V on the NUC)>Cisco 2690L-16PS switch>Sonore opticalModule (Uptone LPS 1.2)>

LIVING ROOM: Sonore opticalRendu Roon version (Sonore Power Supply)> Shunyata Venom USB>Naim DAC V1>Witchhat DIN>Naim NAP 160 Bolt Down>Chord Rumor 2>Audio Physic Compact Classics. OFFICE: opticalModule> Sonore microRendu 1.4> Matrix Mini-i Pro 3> Naim NAP 110>NACA5>KEF Ls50's. BJC 6a and Ghent Catsnake 6a JSSG ethernet; AC cables: Shunyata Venom NR V-10; Audience Forte F3; Ice Age copper/copper; Sean Jacobs CHC PowerBlack, Moon Audio DIN>RCA, USB A>C. Isolation: Herbie's Audio Lab. 

Link to comment
13 hours ago, wakka992 said:

can't you just solder a wire to the ground of a RCA plug? assuming you've plug laying around...

same for 3.5mm jack I assume

 

 I did that for my Teac STB which is connected to my DAC via Coax SPDIF, for a small but worthwhile audible improvement.

Just plug it into an unused RCA socket ./

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

Link to comment
13 hours ago, wakka992 said:

can't you just solder a wire to the ground of a RCA plug? assuming you've plug laying around...

same for 3.5mm jack I assume

 

I would, if I could solder, and had all the tools to do so!

 

2 minutes ago, sandyk said:

 

 I did that for my Teac STB which is connected to my DAC via Coax SPDIF, for a small but worthwhile audible improvement.

Just plug it into an unused RCA socket ./

 

I'm going to do the same, once these puppies come in:

 

61MUVC-l8VL._SL1001_.jpg

 

Reminds me of the flying toasters screensaver from the early 90s!

Link to comment

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.

 

 

 

Link to comment

Hi Em2016

 

My system mirrors yours, IsoRegen/LPS-1 into Chord Hugo. I grounded the IsoRegens usb output and found it to be helpful, however, once i added a ground to the meanwells dc output sq took a backwards step. In my system, the best outcome was achieved by forgoing the IsoRegen ground and adopting the meanwell ground alone.

 

 

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



×
×
  • Create New...