SMPS and grounding

[One and a half]

2 hours ago, sandyk said:

 

 What  if we have a breakdown between Primary and Secondary sides of a 5V SMPS supply ?

Are they completely immune to such things due to their design ?

Just asking.

If there's a complete breakdown,  then the 0V being earthed will blow a fuse or breaker and the downstream circuit is wrecked.  

This could happen with a flashover from primary to secondary,  but this would be caused by the primary shorting (massive collapse of the field)  and protection devices would work again in that case.

 

Transformers are very reliable if they are selected for the right duty and don't get hit with any direct lightning strikes. 

[sandyk]

Just now, One and a half said:

If there's a complete breakdown,  then the 0V being earthed will blow a fuse or breaker and the downstream circuit is wrecked.  

 

 That is my main concern about using a direct earth instead of something like a low value 0.25W resistor (e.g.22 ohms or a little higher) which would very quickly go o/c and hopefully protect the downstream circuit.

A resistor of that value should be just as effective as a direct earth given the very high impedance leakage source.

[One and a half]

1 minute ago, sandyk said:

 

 That is my main concern about using a direct earth instead of something like a low value 0.25W resistor (e.g.22 ohms or a little higher) which would very quickly go o/c and hopefully protect the downstream circuit.

A resistor of that value should be just as effective as a direct earth given the very high impedance leakage source.

Restricted earth fault, you would need to work out if the resistor passed enough current to activate an overvoltage protection, or out of balance system.

[rickca]

9 minutes ago, sandyk said:

 

 That is my main concern about using a direct earth instead of something like a low value 0.25W resistor (e.g.22 ohms or a little higher) which would very quickly go o/c and hopefully protect the downstream circuit.

A resistor of that value should be just as effective as a direct earth given the very high impedance leakage source.

Maybe that's why the Groundhog measures at 15 ohms as reported by @austinpop.  Is iFi smart enough to do this on purpose?

[R1200CL]

4 hours ago, JohnSwenson said:

Hi guys, I was going to post on this, but these recent posts are just what I have wanting to talk about.

 

I've been doing a bunch of measurements on both Ethernet and USB cables. This has to do with leakage being common mode, radiation from cables may be very different than commonly assumed.

 

Ethernet:  leakage current is common mode, the same on both data wires.

    UTP:  No shield, common mode leakage it radiated very well from the twisted pair. Twisted pair makes no difference, both wires have   the same thing

  STP: Shielded cable, metal connectors at each end, shield connected from box to box. Leakage goes right through shield, the shield makes a great antenna radiating the leakage.

 STP: shield is not connected to either end. Provides a little bit of attenuation of radiation due to leakage current.

 STP: JSSG, a single wire connect both ends of shield, ends of shield NOT connected to boxes. Since the shield is not connect to the boxes leakage cannot flow through shield. The wire connecting both ends of the shield does a very good job of blocking the radiation from the leakage current.

 

So for a system that DOES have leakage going through the Ethernet cable, all but the last will be radiating low frequency noise from the cable which can be picked up by normal audio cables and devices.

 

USB cables have a similar situation

 

Normal cable: shield connected at both ends, leakage flows through shield, radiating leakage.

Un-shielded cable. Leakage flows through ground wire and also VBUS and data. Due to geometry of cable and how leakage gets into data pair, does not radiate as good as UTP. less radiation that regular cable. May be why some people like un-shielded cables.

Un-shielded just data pair. With no ground wire and VBUS wire, leakage through just data pair is quite a bit less, producing significantly less radiation than normal cable.

normal cable, but JSSG, shield NOT connected between boxes. The JSSG shield blocks a very large amount of the radiation from leakage. Still has full ground, VBUS and data wires, without leakage radiation.

 

This leads me to think that a lot of systems are actually picking up noise due to radiation from leakage flowing through the Ethernet and USB cables. This may actually be why some people like some weird configurations of cables.

 

Note that this has absolutely NOTHING to due with the actual data going through the cable, it is just due to leakage from power supplies going between between boxes through the digital cables.

 

Note that this is from leakage, if you stop the leakage from flowing through the cable, all this cable stuff above makes no difference.

 

Just some more food for thought.

 

John S.

 

 

Very interesting. USB has power, so can Ethernet, called PoE.

 

Did you make any measurements, or have any taughts about PoE ? Any reason to stay away from PoE ?

 

A well designed AE may be interesting using PoE, or ?

(We would still need the LPS-1 to power a PoE switch,of cause ?)

[JohnSwenson]

4 minutes ago, R1200CL said:

 

Very interesting. USB has power, so can Ethernet, called PoE.

 

Did you make any measurements, or have any taughts about PoE ? Any reason to stay away from PoE ?

 

A well designed AE may be interesting using PoE, or ?

(We would still need the LPS-1 to power a PoE switch,of cause ?)

PoE is done very differently to USB power. USB has separate + and - power wires (Ground and VBUS), PoE is sent over the data wires, using the Ethernet transformers to separate DC from signal.

 

All the PoE powering systems I have ever seen use SMPS to power things, PoE can use quite high voltages which makes things a little difficult for LPS powering, but certainly could be done if someone wanted to work hard enough at it.

 

I have not spent any time measuring a PoE system for leakage and leakage ration from cables, but just a quick thought on the subject does not point at there being any significant difference than non-PoE systems.

 

John S.

[R1200CL]

  Yes 600 mA @ max 42,5 DC

 

 

 

Well, we will just have to leave that option for a while...

 

http://www.downloads.netgear.com/files/GDC/GS105PE/GS105PE_IG_7Nov2013.pdf?_ga=2.190938346.1173225729.1510450072-1964208348.1508755354

 

 

[One and a half]

Information on the ifi Galvanic 3.0 construction. The input USB 3 connector's shell is insulated from the output's shell and the case. The output USB A connector's shell is connected to the case. So the shell casing is not continuous and is created. I thought to bond the case to the source computer's case, but this would 'short circuit' the design, and didn't go ahead with the bonding. I thought that could alleviate audible ticks generated by the ifi Galvanic 3.0 which recently surfaced. The solution to that problem was to remove the  ifi Galvanic 3.0 and replace it with an Intona. 

 

I did bond the ifi Micro USB 3.0's case to the source computer's case with a short 17cm 10 AWG wire. An improvement, perhaps a little cleaner, really splitting hairs though. The next step is for a 9V linear power supply for the ifi Micro USB 3.0 instead of the supplied iPower. The Acopian LPSU is working out well for the Icron Ranger, made a big difference to the noise lowering, with the 0V solidly grounded.

[Summit]

I must admit I don’t understand how leakage current can be transmitted by the shield of a cable. My understanding of shield is that it isolate one device from another. Nevertheless leakage current is only one of many aspect that can infect SQ. The shield on digital cables are there for a reason, to reduce electrical noise from affecting the signals and to reduce electromagnetic radiation that can interfere negatively on other devices. To my ear and in my system a dubbed shielded Supra CAT 8 give me much better sound than an unshielded BJC CAT 6.   

[R1200CL]

JSGT done simply:

 

 

I think this is as is as good as anything else. 

 

Just wrap the wire around the barrel of the Marvell 5,1 plug, and insert it. 

 

Anyone disagree ?

AWG 14

[octaviars]

8 minutes ago, R1200CL said:

JSGT done simply:

 

 

I think this is as is as good as anything else. 

 

Just wrap the wire around the barrel of the Marvell 5,1 plug, and insert it. 

 

Anyone disagree ?

AWG 14

 

This is the easiest way of trying grounding the negative side of the PSU. I have a cableshoe that is 5,5mm inside that I put on the DC plugg before I inserted it in to my Netgear GS108 that feeds my music system. When my system is fully built I will make more permanent connections but to try it the cableshoe works really well.

[R1200CL]

If no one yet hasn’t confirmed:

I just plugged LPS-1 into a 12V Netgear ProSAFE GS108.

And it works. 

 

 

http://www.downloads.netgear.com/files/GDC/datasheet/fr/GS105-GS108.pdf

 

I was lucky enough to find a used Cisco GS 108D-08. 

Will try that one as well next weekend. 

 

Later I will open up and take pictures of some switches that I have available. I have the FS 105 available as well. 

 

[octaviars]

9 minutes ago, R1200CL said:

If no one yet hasn’t confirmed:

I just plugged LPS-1 into a 12V Netgear ProSAFE GS108.

And it works. 

 

Most network stuff have a DC/DC converter that will work at lower DC voltages than the PSU that came with it. At a serten point the converter will stop regulating and the switch turns of. I have a GS108 and I can test it with my adjustable DC aggregate if you would like to know how it behaves at serten voltages and what happens to the amperage.

[R1200CL]

20 minutes ago, octaviars said:

 

Most network stuff have a DC/DC converter that will work at lower DC voltages than the PSU that came with it. At a serten point the converter will stop regulating and the switch turns of. I have a GS108 and I can test it with my adjustable DC aggregate if you would like to know how it behaves at serten voltages and what happens to the amperage.

 

Thanks for offering. No need. The point was more to inform those that may consider any of the mention switches for a JSGT, that f they like, they can use the LPS-1. 

 

As I did this on a Netgear 8 port Gigabit switch, I think we are quite covered with the 5 port version as well as the FS version with 10/100. 

 

As picture shows I’ve only connected two plugs. I suppose connecting more doesn’t matter, as well as the whole idea here is to use those switches before an AE.

 

Is it a Gophert you have ? (Yes, I see now from answer below)

I have one myself. Have not used it yet. The plan is to test it on my SonicTransporter i5, as two LPS-1 in series didn’t manage. 

 

 

[octaviars]

Did a quick test with my GS108 switch before your answer @R1200CL As you can se I have 4 connected ethernetcables and 3 of them were in use when I did the test.

 

12V

 

 

9V

 

 

7V

 

 

Stops regulating around 5,2V and starts back up again at 5,5V.

 

Amperage is 0,13A at 12V and 0,21A at 7V but that is just the DC/DC regulator doing what is does. If it is a good thing to run it on 7V for a long time I dont know.

[lmitche]

19 hours ago, JohnSwenson said:

Hi guys, I was going to post on this, but these recent posts are just what I have wanting to talk about.

 

I've been doing a bunch of measurements on both Ethernet and USB cables. This has to do with leakage being common mode, radiation from cables may be very different than commonly assumed.

 

Ethernet:  leakage current is common mode, the same on both data wires.

    UTP:  No shield, common mode leakage it radiated very well from the twisted pair. Twisted pair makes no difference, both wires have   the same thing

  STP: Shielded cable, metal connectors at each end, shield connected from box to box. Leakage goes right through shield, the shield makes a great antenna radiating the leakage.

 STP: shield is not connected to either end. Provides a little bit of attenuation of radiation due to leakage current.

 STP: JSSG, a single wire connect both ends of shield, ends of shield NOT connected to boxes. Since the shield is not connect to the boxes leakage cannot flow through shield. The wire connecting both ends of the shield does a very good job of blocking the radiation from the leakage current.

 

So for a system that DOES have leakage going through the Ethernet cable, all but the last will be radiating low frequency noise from the cable which can be picked up by normal audio cables and devices.

 

USB cables have a similar situation

 

Normal cable: shield connected at both ends, leakage flows through shield, radiating leakage.

Un-shielded cable. Leakage flows through ground wire and also VBUS and data. Due to geometry of cable and how leakage gets into data pair, does not radiate as good as UTP. less radiation that regular cable. May be why some people like un-shielded cables.

Un-shielded just data pair. With no ground wire and VBUS wire, leakage through just data pair is quite a bit less, producing significantly less radiation than normal cable.

normal cable, but JSSG, shield NOT connected between boxes. The JSSG shield blocks a very large amount of the radiation from leakage. Still has full ground, VBUS and data wires, without leakage radiation.

 

This leads me to think that a lot of systems are actually picking up noise due to radiation from leakage flowing through the Ethernet and USB cables. This may actually be why some people like some weird configurations of cables.

 

Note that this has absolutely NOTHING to due with the actual data going through the cable, it is just due to leakage from power supplies going between between boxes through the digital cables.

 

Note that this is from leakage, if you stop the leakage from flowing through the cable, all this cable stuff above makes no difference.

 

Just some more food for thought.

 

John S.

 

Hi John, 

 

Many thanks for sharing this information on cable shielding. Two questions please:

 

In your parlance we have shield connected, shield unconnected and no shield.

Does adding a disconnected shield layer with the "jssg" ground shield return wire accomplish the same reduction in radiated rfi emi in all three cases?  I am thinking of adding tinned copper sleeving with an insulated 14 awg stranded and insulated wire on the outside.

 

https://www.amazon.com/Tinned-Copper-Metal-Braided-Sleeving/dp/B01BIBQESG

 

I appreciate that with the shield connected cable adding the sleeving will not stop any leakage current flow through the existing connected shield.  Nevertheless will radiation be reduced?

 

The additional tinned copper sleeving may be a cheap and simple way to accomplish the benefits of the JSSG design for existing ethernet and usb cables.

 

Thanks again,

 

Larry

 

P.s. I am very much enjoying the ground shunt trick on the two Sigma 11 power supplies powering my USB HDD enclosure and repurposed Netgear switch. Thank you very much.

[d_elm]

2 hours ago, R1200CL said:

If no one yet hasn’t confirmed:

I just plugged LPS-1 into a 12V Netgear ProSAFE GS108.

And it works. 

 

I found an LPS-1 at 7V will power a GS105v5,12V, with two active ports but not an FS105v3, 12V.  I am using an 8.4V battery for the latter.

 

[Superdad]

3 hours ago, d_elm said:

...but not an FS105v3, 12V. 

 

That matches with what I reported last week.  For the FS105/12V, 7.5V works fine but 7V was not enough.

 

Interesting about the GS108.  Guess that the switching regulator (and supporting power circuitry) used in that model tolerates a wider input voltage range.

[Superdad]

13 hours ago, One and a half said:

The solution to that problem was to remove the  ifi Galvanic 3.0 and replace it with an Intona. 

 

Of course I am biased, but I own both the above devices, so I can suggest to you that the most musical solution might be to replace both with an ISO REGEN!   Don't know that you have ever tried one Gary.

--Alex C.

[JohnSwenson]

8 hours ago, lmitche said:

Hi John,

https://www.amazon.com/Tinned-Copper-Metal-Braided-Sleeving/dp/B01BIBQESG

 

I appreciate that with the shield connected cable adding the sleeving will not stop any leakage current flow through the existing connected shield.  Nevertheless will radiation be reduced?

 

Yes a separate shield around the existing cable, when properly connected with a wire end to end will block a large amount of the emissions from the existing cable.

 

John S.

[lmitche]

17 minutes ago, JohnSwenson said:

Yes a separate shield around the existing cable, when properly connected with a wire end to end will block a large amount of the emissions from the existing cable.

 

John S.

Thanks John,

 

I am curious, what is the theory of operation for the end to end wire? Does it make the cable a poor antenna? 

 

Adding the tinned copper sleeving and wire to the Lush USB cable this afternoon had a noticably positive impact. I'll do the same to my ethernet and usb 3.1 cables later in the week.

[gstew]

1 hour ago, lmitche said:

Thanks John,

 

I am curious, what is the theory of operation for the end to end wire? Does it make the cable a poor antenna? 

 

Adding the tinned copper sleeving and wire to the Lush USB cable this afternoon had a noticably positive impact. I'll do the same to my ethernet and usb 3.1 cables later in the week.

Larry,

 

See here:

 

Greg in Mississippi

 

[lmitche]

30 minutes ago, gstew said:

Larry,

 

See here:

 

Greg in Mississippi

 

Thanks Greg,  sorry forgot that one, LOL.  John you are amazing!

[Speed Racer]

I would imagine the iFi iPower would be an excellent power supply if you tied the negative DC output to ground as suggested by John in this thread. Does anyone have measurements of the iFi thusly grounded?

 

Forgive me if I missed said results if already posted here as I did not see them. 

[Les Habitants]

3 hours ago, Speed Racer said:

I would imagine the iFi iPower would be an excellent power supply if you tied the negative DC output to ground as suggested by John in this thread. Does anyone have measurements of the iFi thusly grounded?

 

It is, but I have no measurements.

I believe it was stated some pages ago that all of the SMPS units tested benefitted from this shunt technique.