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JohnSwenson

SMPS and grounding

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2 hours ago, rickca said:

So to use John's grounding technique, does this mean we now need two outlets for each SMPS (unless grounding multiple SMPS from the same wire)?  I'm impossibly dense about electrical things.

 

I'm also impossibly dense about electrical things, but I think the answer to your question is 'yes.'

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BigGuy   
2 hours ago, rickca said:

So to use John's grounding technique, does this mean we now need two outlets for each SMPS (unless grounding multiple SMPS from the same wire)?  I'm impossibly dense about electrical things.

You and I are not dense...just uneducated on the topic.

 

I was pondering this 2 plug issue myself.  Can the two SMPS plugs be plugged into a power strip that  is modified properly and how could this be done?  I ran out of AC duplexes which are on the same master panel leg some time ago! 

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sandyk   

 Is this SMPS earthing really a problem generally, other than mainly with USB Audio where SMPS PSUs may be in use ?

I measure around 99V AC  from the "earth" side of the output sockets on a TEAC HDB 850 STB to mains earth.

 However, with Coax SPDIF connected from it to my DAC, which is connected to an earthed Class A Power amplifier, or HDMI plugged from it into my TV, which also has an Oppo 103 connected to it via HDMI, there is no leakage voltage measurable.

Could it be that adding an additional earth to the SMPS powered devices 0V rail, MAY in a situation such as this, where earthing is already likely to be optimal, result in some minor degradation ?

I also fail to see the need for a direct earth connection, when this leakage voltage is at a fairly high impedance, to use direct earthing which could possibly introduce a degree of earth loop if not carefully implemented, when a series low value resistor to earth (e.g. 10 or 22 ohms, or even higher) should have a similar effect ? 

Alex

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opus101   
40 minutes ago, sandyk said:

 I measure around 99V AC  from the "earth" side of the output sockets on a TEAC HDB 850 STB to mains earth.

 However, with Coax SPDIF connected from it to my DAC, which is connected to an earthed Class A Power amplifier, or HDMI plugged from it into my TV, which also has an Oppo 103 connected to it via HDMI, there is no leakage voltage measurable.

 

 

There's the problem in a nutshell - the STB leakage current is now travelling through your DAC - in through the digital input and out again at analog outputs. Presumably from this, it doesn't have an input transformer. Once those noise currents are inside the DAC itself there's no telling what damage they're doing to your SQ.

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sandyk   
45 minutes ago, opus101 said:

There's the problem in a nutshell - the STB leakage current is now travelling through your DAC - in through the digital input and out again at analog outputs. Presumably from this, it doesn't have an input transformer. Once those noise currents are inside the DAC itself there's no telling what damage they're doing to your SQ.

 

Given that this DIY DAC readily outperformed a Bricasti M1, the damage would have to be quite minor. Unfortunately there is no room to install a Coax SPDIF transformer.

The "earth reference''  right through the chain, is via 10 ohm resistors to PCB "earth" at the L and R inputs  of the Class A Power Amplifier. Neither the DAC, or Preamp have their  0 volts lines connected to mains earth via the power supply either, and the Source switch in the Preamp only connects through the "earth" side of the selected Input.

 

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opus101   
2 minutes ago, sandyk said:

 

Given that this DIY DAC readily outperformed a Bricasti M1, the damage would have to be quite minor. Unfortunately there is no room to install a Coax SPDIF transformer.

The "earth reference''  right through the chain, is via 10 ohm resistors to PCB "earth" at the L and R inputs  of the Class A Power Amplifier. Neither the DAC, Preamp or P.A. have their  0 volts lines connected to mains earth via the power supply either, and the Source switch in the Preamp only connects through the "earth" side of the selected Input.

Only their  metalwork is connected to mains earth.

Which particular DAC is it? Given its DIY then the internal grounding can be verified to see whether it diverts the noise currents around the sensitive analog circuits. You needn't break the earth loop with a digital transformer, you could put transformers externally on the analog outs (for example).

Are the RCA socket outers on your poweramp wired direct to chassis (mains earth) or are they routed onto the PCB? If the latter then all your noise current runs through that 10ohm resistor.

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sandyk   
26 minutes ago, opus101 said:

Are the RCA socket outers on your poweramp wired direct to chassis (mains earth) or are they routed onto the PCB? If the latter then all your noise current runs through that 10ohm resistor.

 

 

No, the sockets are not grounded to chassis. They connect via the 10 ohm "EARTH LIFT " resistors on  the PCB , which is a well  accepted, and  common method of reducing earth loop problems.

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sandyk   
40 minutes ago, opus101 said:

you could put transformers externally on the analog outs (for example).

 

 

YUK !!!

 

Nobody in their right mind would do this to an amplifier with very close to 4 Zeroes in it's distortion measurements, and a high S/N ratio, along with a very good 3D presentation on good material.

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opus101   
16 minutes ago, sandyk said:

 

No, the sockets are not grounded to chassis. They connect via the 10 ohm "EARTH LIFT " resistors on  the PCB , which is a well  accepted, and  common method of reducing earth loop problems.

 

'Ground lift' resistors date back to ye olde days when there was a strong likelihood the source component would present a low impedance to mains earth on its 0V and SMPSUs weren't as prevalent as they are nowadays. When the noise generator has a high impedance (as here) they're not providing much benefit.

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opus101   
19 minutes ago, sandyk said:

 

Nobody in their right mind would do this to an amplifier with very close to 4 Zeroes in it's distortion measurements, and a high S/N ratio, along with a very good 3D presentation on good material.

 

It has been applied to a Modulus86 amp (replacing its IC input stage) with I forgot how many zeroes in its THD number (at least 3 I am sure of) with beneficial sonic results.

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sandyk   
42 minutes ago, opus101 said:

'Ground lift' resistors date back to ye olde days when there was a strong likelihood the source component would present a low impedance to mains earth on its 0V and SMPSUs weren't as prevalent as they are nowadays.

 

Many designers still use earth lift resistors for their benefits.

Silicon Chip magazine for example, has published some of the lowest distortion designs, and they still use "earth lift" resistors . (Typically .0006% for their SC ULD3)

As far as "ye olde days" goes, that's exactly what using expensive transformers is when there are far better design alternatives these days.

Have you read any of the Power Amplifier Design Handbooks written by highly respected U.K. author Douglas Self, for example ?

 

P.S.

 My own DIY system is fully D.C. coupled from the DAC, through the Preamp, and the !5W/Ch. Class A Amplifier. 

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opus101   
2 minutes ago, sandyk said:

 

Many designers still use earth lift resistors for their benefits.

Silicon Chip magazine for example, has published some of the lowest distortion designs, and they still use "earth lift" resistors . (Typically .0006% for their SC ULD3)

As far as "ye olde days" goes, that's exactly what using expensive transformers is when there are far better design alternatives these days.

Have you read any of the Power Amplifier Design Handbooks written by highly respected U.K. author Douglas Self, for example ?

 

Curious - what are the sonic benefits of having 3 zeroes in the distortion figure?

 

Long been a fan of Doug Self's books and his EWW articles. Think I might have one of the first editions of APAD - I got it when I was working as an amp designer professionally.

 

What 'alternatives' sound better than transformers for input and output isolation? I wind them myself so your 'expensive' is under $2 in materials for me.

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sandyk   
10 minutes ago, opus101 said:

Curious - what are the sonic benefits of having 3 zeroes in the distortion figure?

 It is a matter of record that some amplifiers such as some of the Halcro designs with even lower distortion figures are acclaimed for their 3D presentation.

 My own Class A amplifier has been nicknamed by friends as " The Holo Amp"(as in Holographic)

It uses a front end balancing scheme, that can be readily further refined by using 1 additional transistor..

The claimed improvement was verified by DIY Audio members.

http://www.diyaudio.com/forums/solid-state/133018-current-mirror-discussion-15.html

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opus101   
10 minutes ago, sandyk said:

 It is a matter of record that some amplifiers such as some of the Halcro designs with even lower distortion figures are acclaimed for their 3D presentation.

 

 

I'm unclear if you're merely claiming correlation or causation?

 

Back to an earlier question still outstanding - which DIY DAC are you using?

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sandyk   
23 minutes ago, opus101 said:

Back to an earlier question still outstanding - which DIY DAC are you using?

 

 I am using a highly modified version of a published design from Silicon Chip magazine.

 

Attached is a photo of my own Class A amplifier. The front end is powered via by a modified version of a John Linsley Hood designed PSU Add-on. ( http://users.tpg.com.au/gerskine/greg/default.htm  - See Power Supplies)

 Quite a few were also constructed by members of a U.K. based forum using PCBs designed by members.

 

BTW, this is now all well off topic, and will be removed by Alex C.

zHSwmJ.jpg

spcbss.jpg

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Cornan   
1 minute ago, jaaptina said:

Has anyone actually experienced a boost in SQ after applying John's SMPS grounding hack? I have read through the posts but haven't read about someone trying this in his system currently. 

 

Yes, I have experianced a boost in SQ. The DC - grounding of my floating SMPSs connected to a Entreq Minimus grounding box improved SQ, possibly by blocking a leakage loop going to both my ISO Regen and AQVOX switch-8. Before the DC- grounding I could use ISO Regen alone without getting a hollow sound with GI on. I had a Regen Amber pre the ISO Regen and the GI off until I tried this little "tweak". Also grounding the AQVOX switch-8 improved SQ a lot before the DC- grounding. After the DC- grounding the AQVOX grounding did´nt give as much SQ boost as before.

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Ryelands   
33 minutes ago, jaaptina said:

Has anyone actually experienced a boost in SQ after applying John's SMPS grounding hack?

Not quite a straight answer to your question but I have three LPS-1s each driven by a stock SMPS (Meanwell ?). If I connect the MWs straight to the mains, the SQ is not as good as it is if I connect them via Jon Risch-style isolating transformers. The improvment is marked and readily repeatable. Whether it's down to a quirk in my system, I can't say but it's a damn nuisance because the transformers are crying out for a case on both aesthetic and safety grounds which I really, really don't want to make. And they take up too much space.

 

So, last night, I tried the tweak (the JSGT?) on the MW that powers the DAC's clock and thus (or so I guessed) the one most likely to show up an SQ loss. Several hours in and so far, so good - no detectable SQ loss compared to the isolators. I'll be trying the second MW shortly and will report back.

 

Should anyone feel the temptation to ask what the effect of using the isolators and the JSGT might be, resist it . . .

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On 9/26/2017 at 2:52 AM, JohnSwenson said:

I've been experimenting with some ways to make the SMPS a little easier or applicable to a broader range of equipment. First off is a way to use it with equipment that does not have a 5.5x2.1 barrel jack.

Ground_adapter_size.thumb.jpg.5e7c75d26eb2db90b687f7955902e2b2.jpg

 

I found another I had on hand, in this case the 7.5V Mean Well, this was exactly the voltage my switch took, IT plugs into the adapter, then a 5.5x2.1 to something else is used to plug into the device. In this case it was one of the adapters that came with the iPower. This works great. Using this technique I was able to ground the power to a bunch of different devices that had different plug sizes.

 

Both Amazon and Ebay have kits of these adapters available which include many different plug types.

 

Next up is an interesting kit from iFi called the Groundhog. It has a gounding system and several adapters to ground equipment in various ways. The one most appropriate is this:

Groundhog.thumb.jpg.47718bfe631b6bb4f9fa955284d1046c.jpg

 

This kit is unusual, it contains an IEC SOCKET, not a plug, you plug in a standard IEC power cord for your country. Most of you will already have several of these in your cable drawer. It doesn't matter what the country is, the IEC end is the same so they will plug right into the Groundhog. They call the adapter I show plugged in the "DC Spade", it is actually a little clip designed to clip onto the barrel of a 5.5 plug, thus grounding it. Clip it onto the barrel, then just plug it in.

 

This replaces the adapter shown in the first post with an off the shelf system you can buy, you don't have to build anything yourself. It is not dirt cheap, ($49), but for those that don't want to deal with building the adapter it is a nice alternative. It does exactly the same thing - it grounds the negative DC output of a power supply.

 

I hope this makes it a bit easier for people to try this approach.

 

John S.

@JohnSwenson , i have two questions regarding to iFI Groundhog:-

 

1- Will the IsoRegen + Lps-1 can benefit from Groundhog?

 

2- And does the Groundhog solve the issue of ground loop in some systems when the Isolation is enabled in IsoRegen like what i have?

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Superdad   
1 hour ago, sadekkhalifa said:

I have two questions regarding to iFI Groundhog:-

 

1- Will the IsoRegen + Lps-1 can benefit from Groundhog?

 

Shunting SMPS leakage currents is most always a good thing.  (And yes, even a bit for an LPS-1; We will present our findings about this at a later date.)

 

1 hour ago, sadekkhalifa said:

2- And does the Groundhog solve the issue of ground loop in some systems when the Isolation is enabled in IsoRegen like what i have?

 

I don't recall your particular issue, but most of the folks that experience issues with Silanna-based USB galvanic isolation (this includes iGalvanic users too) suffer from lack of good grounding (typically on the downstream side), not "ground loops."

The solution to that is generally to ground the downstream USB input (see my long post here: https://www.computeraudiophile.com/forums/topic/31877-iso-regen-listening-impressions-kicked-off-with-some-measurements/?page=26&tab=comments#comment-714912).

While the single wire solution I present is cheaper, the Groundhog solution can do the same thing for the ISO REGEN--but only if you use it on the DC input jack of the ISO REGEN.  Putting it on the DC input jack of the LPS-1 will not help any "lack of ground ticks/disconnects," as the output of the LPS-1 is completely "floated."

 

--Alex C.

 

 

 

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6 minutes ago, Superdad said:

 

Shunting SMPS leakage currents is most always a good thing.  (And yes, even a bit for an LPS-1; We will present our findings about this at a later date.)

 

 

I don't recall your particular issue, but most of the folks that experience issues with Silanna-based USB galvanic isolation (this includes iGalvanic users too) suffer from lack of good grounding (typically on the downstream side), not "ground loops."

The solution to that is generally to ground the downstream USB input (see my long post here: https://www.computeraudiophile.com/forums/topic/31877-iso-regen-listening-impressions-kicked-off-with-some-measurements/?page=26&tab=comments#comment-714912).

While the single wire solution I present is cheaper, the Groundhog solution can do the same thing for the ISO REGEN--but only if you use it on the DC input jack of the ISO REGEN.  Putting it on the DC input jack of the LPS-1 will not help any "lack of ground ticks/disconnects," as the output of the LPS-1 is completely "floated."

 

--Alex C.

 

 

 

Thanks Alex for your feedback and support.

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rickca   
21 minutes ago, Superdad said:

While the single wire solution I present is cheaper, the Groundhog solution can do the same thing for the ISO REGEN--but only if you use it on the DC input jack of the ISO REGEN.

So that's different than grounding the downstream USB input, right?  

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