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Common Mode Noise

70.181.190.47
Posted on January 24, 2017 at 10:56:04
Mercman
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Posts: 6581
Location: So. CA
Joined: October 20, 2002



I have been evaluating the USB input of the Ayre QX-5 Twenty with the microRendo. I found the sound to be a bit dark and not particularly well defined in the mid bass and bass compared to what I was hearing from the Ethernet input. My friend suggested to me that there might be leakage currents / common mode noise involving my Sonore Signature Power Supply and the microRendu. He made a small filter to go inline with the power supply.

"He felt that if this common mode filter changes the sound, that's an indication that there are common mode noise currents flowing through the path that includes your power supply for the microRendu. No common mode noise currents, no change, because there is nothing to filter."

Using the filter, the sound improved by a significant amount just about matching the sound quality I was hearing with the Ethernet connection. My friend is now building an even better filter for me.

Check out the video at AudioStream:

CES 2017: A Conversation with Juergen Reis (MBL) and John Atkinson (Stereophile)

Juergen discusses the back door leakage currents that are found in the complete system that can effect our evaluation of cables and other components besides having a negative impact on the sound of our systems.

 

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RE: Common Mode Noise, posted on January 24, 2017 at 11:10:31
AbeCollins
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Posts: 46280
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Contributor
  Since: February 2, 2002
Cool. I wonder what ferrite core he used for his common mode choke.

 

RE: Common Mode Noise, posted on January 25, 2017 at 04:22:34
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
 Yep.
This or that filter at the right spot can have quite an impact.
However. There are cases (too much filtering) where things get worse!
Again - interesting to see that your insanely high priced gear is
not able to cope with it.

Advise related to your photo:
First u should cleanup your under-the-hood cable mess.
That mess acts like antennas and might cause other interferences.

Keep mains separated from DC and NF signal cables.
And also keep HF stuff like network and USB cables separated from the rest.
And review your grounding scheme. Proper grounding is key!

Hint:
U could e.g. cut and fold cardboard chunks to act as cable bridges
and cable runs.

Another hint:
Keep the DC cables as short as possible!

And also keep in mind that additional jacks and plugs cause issues
on their own.


Good luck


-----------------------------------------------------------------

blog latest >> The Audio Streaming Series - tuning kit pCP

 

RE: Common Mode Noise, posted on January 25, 2017 at 04:32:51
Mercman
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Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Thanks for the suggestions. Many of those wires are gnd wires for Synergistic cables ,Tranquility Bases, and UEF Gnd block.

 

RE: Common Mode Noise, posted on January 25, 2017 at 16:50:49
Ugly
Audiophile

Posts: 2912
Location: Des Moines, WA
Joined: August 22, 2006
 If just putting the core in there made a positive difference the three stage filter would be worth a try. Just adding the caps creates much more impedance to common mode noise than just the core alone.

 

From another thread..., posted on January 25, 2017 at 16:52:48
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 How can your, or anyone else's system be optimised when you discover such setup up alterations to SQ. The fact is: PSs all sound different.

I am serious.

 

Best see a doctor about that wound on you leg...., posted on January 25, 2017 at 19:36:46
Ivan303
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Posts: 48887
Location: Cadiere d'azur FRANCE - Santa Fe, NM
Joined: February 26, 2001
 where 'fmak' been nipping at it!




First they came for the dumb-asses
And I did not speak out
Because I was not a dumb-ass

 

RE: Common Mode Noise, posted on January 26, 2017 at 03:20:39
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Thanks. This filter was just a test. Something is being built with a nice blue case :-)

 

RE: From another thread..., posted on January 26, 2017 at 03:23:25
Mercman
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Posts: 6581
Location: So. CA
Joined: October 20, 2002
 I think the issue is that you are really talking about perfection and not optimization.

 

RE: From another thread..., posted on January 26, 2017 at 05:18:39
fmak
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Posts: 13158
Location: Kent
Joined: June 1, 2002
 No. Just think. What you 'optimise' is not optimisation if small changes in your system brings either better or worse SQ.

 

RE: From another thread..., posted on January 26, 2017 at 06:09:51
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Since you don't have any respect for me, given your comments at Critic, why bother even discussing things with me. You have made your feelings on this issue as clear as you can.

And in the end, everything matters.

Enough already!

 

RE: From another thread..., posted on January 26, 2017 at 06:42:13
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 Just think.

Good idea.

What you 'optimise' is not optimisation if small changes in your system brings either better or worse SQ.

False argument - see above. "Optimising" in the PC audio context means configuring an OS to favour audio reproduction, typically by disabling non-audio-related functions. It may, as you argue, be a misuse of the term but the rest of us know what it means even if I prefer to say "slimming". Whatever, a carefully configured OS is more likely to be responsive to minor changes in the overall setup, not less.

In passing and at risk of saying the obvious, the microRendu has not been "optimised", just not bloated in the first place.

Soundchekk is right to say: "Keep mains separated from DC and signal cables; keep HF stuff . . . separated from the rest; review your grounding scheme". And he was right many years ago when he recomended a decentish PSU for the switch that connects to the PC though it was only a start.

Soooo, today's tip?

If you drive an audio PC via ethernet, try running it at 100-BaseT or (better) 10-BaseT. That's an old tip now but the new one (at least I've not seen it anywhere else) is to use LAN cables that connect the green and orange pairs only (pins 1&2, 3&6). Omit or remove 4&5 and 7&8 as 10/100-BaseT doesn't need them. Best use Telegartner plugs and a decent stock LAN cable such as Excel (see link) or, probably, BJ. No need IMHO for boutique products, not even the well-documented Meicord cable. I bought two of those but they're no longer in use. Ditto ViaBlue CAT7, which are as good as Excel CAT6 but much pricier.

I don't know why but the difference in my system made by simply removing the unused pairs was very marked even though I'm already using a fibre-optic link to the server with the local media converter and other gubbins powered by an Uptone "supercapacitor" PSU and separated from the PC by LAN isolators. Viz, the biz. The sound is way better than that from ten-times-the-price Meicord cables and in a different league to Amazonic stock crap. Yup, I've tried them all. I'd wager that it compares well with Audioquest's mega-buck audio bling but that's beyond my reach.

And, yes, my audio PC was "optimised" / "slimmed" till its eyes watered.

HTH

D

 

'back door leakage currents' = ground loops (very, very looong post), posted on January 26, 2017 at 10:32:22
hfavandepas
 Hi Mercman,

Thankx for posting this. It highlights a 'hidden' problem that I also had in my system and probably also many inmates may have in their sound systems without noticing. As for me, I only discovered this hidden problem when I made unplanned changes in power connections because I had too dismantle and re-install my sound system when my living-room needed some fresh painting.

In the end solving noise problems and solving related ground loop problems really paid off in my system!! So I definitely want too encourage other inmates too have a close look at their systems. May be similar sound quality improvements can be made in their systems.

On the other hand, finding and eliminating ground loops and suppressing associated noise problems was very time consuming and a lot of work. I spend much time on reading tutorials and papers, much on experimenting, buying parts, installing them, etc, etc.

So I decided Mercman's post is a good reason for writing down this very, very loooong post about what I tried in my system. Hopefully it will give other inmates an impression if 'hunting' for ground loops and associated noise problems in their system, might be worth the trouble.

* But first some considerations when I red your post.
While your friends solution focuses on suppressing these noise currents through filtering, you also focus on the pathway these noise currents flow. You point at a video https://www.youtube.com/watch?v=sMmdDLFP4So where Juergen Reis (MBL) discusses the 'back door leakage currents' that are found in complete systems which can have a negative impact on the sound of our systems.
Don't know why Juergen Reis (MBL) calles them 'back door leakage currents' but these 'back door leakage currents' are also better known as: ground loops. Don't know why Juergen chooses too call them: 'back door leakage currents'. (Probably just too make him look smarter and make the problem look more mysterious)

While adding filters too suppress noise is one solution, I was very happy that you also considered pointing at the pathway's these noise currents may use. Changing or eliminating these pathway's may be much more effective than putting a filter on it.
And what to think of: not creating those pathway's in the first place? (through prober system design and/or proper balanced interconnection)

However avoiding or eliminating those pathway's is easier said than done. Especially since many inmates nowadays will have sound systems that are (inter-)connected too:
1. a computer, TV-set, cable-box, streaming device, wired internet, etc, etc.
These consumer grade devices mostly use noisy PSU's and use (potentially problematic!) unbalanced connections.
2. coax-cables from cable-companies or antenna-systems that may introduce an extra (potentially problematic) pathway too the electrical safety ground.
3. consumer equipment that has a build-inn design defect also know as the 'Pin 1 problem'.
Combining all 3 points together make an ideal situation for creating (unintentionally) all kinds of ground loops causing minor (or bigger) sound quality problems.

Like me, most inmates probably will assume that a sound system has no noise problems caused by ground loops, as long there is no 50/60 Hz hum coming from the speakers. But unfortunately ground loops ('back door leakage currents') come in all sorts and can have all kind of (U)HF noise frequencies having negative impact on the digital parts of the sound system.

In his tutorial 'A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing', Jim Brown (vice chair of the AES Standards Committee working Group on Grounding and EMC Practices) makes a bold claim. He suggests that the most common way hum, buzz, and noise enters the circuit board of our music equipment are caused by design defects. Somehow, somewhere the cable shield has a (unwanted) connection too the circuit board ground. On page 5 Jim Brown writes: "Nearly all consumer equipment, including even the most expensive "high futility" gear, is built with this problem. Virtually all computer sound cards have these problems. So do most RS-232 interfaces and nearly all HAM equipment".
Although focused on HAM equipment Jim Brown's tutorial was a must read for me. It helped me a lot. It can be downloaded from: http://audiosystemsgroup.com/RFI-Ham.pdf

Just like you discovered, I also discovered that Jim Brown was right. The sound coming from my system could be improved by a significant amount when attention is paid not to create unwanted ground loops in the first place and/or put filtering on those loops if they can't be avoided.


As already suggested by Soundcheck, cleaning up the cable mess, is a good starting point. But that did not do anything in my system. My system setup is fairly simple and there are not a whole lot of cables.
System setup:
Coax cable -> cable box -> HDMI -> HD TV -> HDMI -> HTPC -> Cat 6 cable -> Merging Hapi -> XLR AES/EBU -> PMC TwoTwo.8
- the HTPC has two network interfaces. One NIC is connected to the Merging Hapi. One NIC connects to a wired LAN cat 5e cable for internet connection.
- With help of a Neutrik impedance transformer the cable box RCA S/Pdif output is connected to the AES/EBU XLR input on the Merging Hapi.
(I use this connection when watching movies on TV. I like too hear the movie sound through my sound system)
- At the cat5e cable which connects too the internet I use a Baaske internet isolators.

Although my sound system is quite simple, I only discovered by accident that my system could sound significantly better. Here's how. For many years I powered my HTPC from a separate power socket across the room. I feared the noise that the ATX computer PSU might throw back into the power line thus spoiling the power input of the amplifiers in my Klein & Hummel O300 active speakers. Only by coincident, I found out that my system definitely sounded much better when the noisy ATX computer PSU was plugged into the same power strip that also powers the active speakers and the Merging Hapi.
Looking back, I know now that I made a huge beginner mistake. Like most computers, also my HTPC has a 'Pin 1 problem' by design. With help of this design defect I had created a massive ground loop that added more noise than the ATX PSU would do by itself.
So now the ATX computer PSU, the active speakers and the Merging Hapi unit are all powered from the same power strip. However, I've added an Epcos power line filter into the ATX PSU power cable. The Epcos power line filter suppresses the noise that the ATX PSU throw's back into the power strip, which again improved the sound by a significant amount !

Because of this success I got heavily infected with 'ground-loop-hunting fever'.
I began reading many internet papers/tutorials on ground loops. Beside Jim Brown's tutorial, I would also recommend reading:
'Understanding, finding & eliminating ground loops in audio & video systems' written by Bill Whitlock, (http://web.mit.edu/jhawk/tmp/p/EST016_Ground_Loops_handout.pdf)
Although it's more of an advertorial (and not exactly a white paper) it still provides in-depth high quality information

After reading Bill Whitlock's paper, I now looked suspiciously at the coax-cable connected too my TV and cable-box. This coax-cable is also connected too the earth's safety ground in my breaker panel closet, possibly creating another ground loop (with help of the unbalanced connections on the TV and the cable box). But unplugging the coax-cable did not improve sound quality.
Also completely disconnecting and removing the TV and cable-box from my sound system (power + interconnects) and running my computer 'headless' did not improve sound quality.

Because Jim Brown also looks at cleaning 'Ethernet trash' in his tutorial, I also tried cleaning 'Ethernet trash' in my home. First I installed a Baaske LAN isolater, but that did not have any impact on sound quality (waste of money). So like Jim Brown suggests I tried too suppress the noise coming from the PSU's that power my LAN network equipment.
In my breaker panel closet I have five cheap switch-mode wall wart style PSU's that power: a cable-internet-router, a managed Netgear ProSafe switch, a WiFi-acces point, a Philips Hue bridge and a NAS.
I decided too install a whole new 6 outlet (earthed) power strip. Onto the strip's power cord (AC side) I installed an Epcos power line filter too suppress noise that those 5 cheap wall wart style PSU's will throw back into the 230 V AC power line.
On the DC side I installed the same common mode choke coils like your friend also installed.
Unfortunately, the sound quality only improved marginally. I don't think this slight improvement was worth the trouble.
But I just red Ryelands tip on removing connections on/to pin 4&5 and 7&8. Ryelands always has tips that work very well. 50% less wires that can create a ground loops and/or provide a path for noise, And also 50% les antenna's to pick up noise. So I'm going to try Ryelands tip ASAP


So what did I learn from this 'ground loop hunting'?
Computers do not only cause problems because they come with a noisy (ATX) PSU. Computers also come with a build-inn design defect: the so called 'Pin 1 problem'.
I don't know which one of the two is more worse. But when combined together (Pin 1 problem + the noisy PSU) it can have serious negative impact on sound quality.
Especially in systems that use unbalanced connections. Ground loops introduced by using unbalanced connections will create noise and also allow noise too travel almost system wide.

Happy 'ground loop' hunting.

I'm curious how other inmates eliminated ground loops and suppress associated noise.
So please do report your findings here on the audioasylum.

Mark

 

RE: 'back door leakage currents' = ground loops (very, very looong post), posted on January 26, 2017 at 11:15:45
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Thanks for this post Mark. I was hoping that inmates might discuss this interesting issue..

 

great post, buddy! n/t, posted on January 26, 2017 at 15:33:38
Ugly
Audiophile

Posts: 2912
Location: Des Moines, WA
Joined: August 22, 2006

 

"Optimising" in the PC audio context , posted on January 26, 2017 at 16:53:41
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 These are words invented by some PC users without any justification or basis. Optimisation in the engineering sense means something totally different. The case in point is simply the advocation of using 2 or 3 'optimising' software suites to get some sort of 'best' sound out of an OS. In Mercman's case, he didn't even use the vendor favoured OS in his review of 'AO'.

 

RE: "Optimising" in the PC audio context , posted on January 26, 2017 at 17:27:24
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 " In Mercman's case, he didn't even use the vendor favoured OS in his review of 'AO'.

The use of Windows 10 Pro was intentional since many more people have Win 10 than Server 2012 or Server 2016. But I've told you this before.

My review clearly discussed that Server 2012, and better yet, Server 2016 could achieve superior results.

 

RE: 'back door leakage currents' = ground loops (very, very looong post), posted on January 26, 2017 at 18:47:32
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 What you have said highlights the basic set up principle in high quality audio replay, analog or digital. Congradulations for doing it.

Which leads to another point. An inmate says he thinks he has a common mode noise problem. He sticks a choke on the PS's lead. He says he has improved the sound. But which is the chicken and where is the egg? For all we know, the new high performance power supply has revealed a flaw in his previous 'optimised' setup, and the problem is elsewhere in his replay chain. So, the hunt for another stick on plaster can start again.

 

RE: Common Mode Noise, posted on January 27, 2017 at 01:51:38
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 It doesn't matter what the cables are. Sound wire routing and dressing 'optimises' your system and Soundchekk is right.

 

RE: "Optimising" in the PC audio context -If, posted on January 27, 2017 at 01:54:35
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 you insist on wireless,networks,and anti virus, your PC system cannot be said to be optimised for best audio replay quality.

 

RE: "Optimising" in the PC audio context -If, posted on January 27, 2017 at 02:18:28
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 I use a fancy Ethernet cable to connect my computer to my LAN and no antivirus software. Fred, you win. My computer isn't optimized, consider it "slimmed".

 

RE: Common Mode Noise, posted on January 27, 2017 at 02:23:47
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Please share images of your system components so that we might learn what an optimized system looks like.

 

RE: Common Mode Noise-get the message, posted on January 27, 2017 at 03:32:57
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 I DO NOT have an optimised system, only one that I can get the best SQ out off. This in my case means the most minimalized OS I can use, with the best computer hardware and power supply I can find.

 

RE: "Optimising" in the PC audio context , posted on January 27, 2017 at 03:34:14
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 Optimisation in the engineering sense means something totally different.

So what DOES it mean "in the engineering sense"? You've been making similar points at intervals for at least eight years - since (IIRC) cics first used the word on this forum - but have yet to put us right. You also, as here, seem to confuse what you feel is mis-use of the word with, again in your opinion, a process that is in and of itself flawed.

To help clarify the first point, I looked up "optimise" in the Collins Dictionary. The definition includes "to find the best compromise among several often conflicting requirements, as in engineering design".

Is that wrong? If so, why? If not, can the word not reasonably include configuring an OS, whether performed entry by entry (as with that team-effort, post-cics cMP2 slimming marathon), by Delphic pronouncement (as with your recent Reg-edit tips) or (for those with better things to do in life) buying a little program that more or less does it automatically? Seems everyone else feels it can.

Dunno why but I also looked up "snipe". Its definition includes "to criticize adversely a person or persons from a position of security".

WRT the second point, I repeat that the microRendu's OS was not "optimised" as in slimmed down from a commerical release but configured from the ground up as and only as an audio player. Mercman's finding that his mega-buck Sonore PSU may perform less than perfectly has nothing to do with whether or not he understands what "optimisation" is. That said, I agree with you, soundchekk and hfavandepas that it's likely a system-level issue that may be eased by BandAid filtering but not necessarily "fixed" by it.

I'll respond separately to hfavandepas' points.

D

 

RE: "Optimising" in the PC audio context -If, posted on January 27, 2017 at 03:34:57
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 Your remote? How does it work?

 

RE: "Optimising" in the PC audio context -If, posted on January 27, 2017 at 04:06:51
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Any computer on the LAN can be a remote. Even the computer that I am tying this on that is connected with an Ethernet cable to the router.

 

RE: Common Mode Noise-get the message, posted on January 27, 2017 at 04:35:57
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 I thought I was doing the same thing. Ok, the word "optimize" is the issue. So what is the definition that you apply to this word?

 

hunt for another stick on plaster, posted on January 27, 2017 at 07:54:24
hfavandepas
 "But which is the chicken and where is the egg?"

Good Question !
Lets consider the chicken = noise source.
The eggs = the noise flow.

First off: The noise source (chicken) does not necessarily needs too be the Sonore Signature PSU.
There may be other noise source candidates along the loop.

Also: system parts that suffer from common noise traveling on the circuit board may be more than 1. The microRendu may suffer, the USB data transport may suffer, the DAC may suffer.

Lets trace the noise flow first (follow the eggs).
When doing so it must be considered that current ALWAYS needs too return to it's source.
So which return path can be used by the noise too travel back?

Is differential mode noise?
(In one wire the noise flows 'up', in the other wire the same noise flows 'down').
Lets hope it is common mode noise.
I don't like too think of an 1.400 dollar Sonore Signature PSU that generously produces differential mode (U)HF noise.

Or is it common mode noise?
(Both wires same noise, same voltage, in same direction).
What direction is the common mode noise flowing?
Towards or from the microRendu?

All I know about Mercman's system is:
? -> Signature PSU -> 2 PSU wires -> microRendu -> USB cable -> Ayre QX-5 Twenty -> ?
? -> UTP LAN cable -> microRendu
- Mercman's friend put's an impedance Z (AC resistance varying according to frequency) on both PSU wires by means of a ferrite choke.
- The PSU wires are between the microRendu mini-pc and the Sonore Signature PSU.
- The impedance on the PSU wires reduces/suppresses the flow of (U)HF noise in the PSU wires
- Mercman enjoys better sound quality.


When trying too find the electrical return path for the common mode noise, I will have too drawn a circle that always includes:
A: the Signature PSU -> 2 PSU wires -> the microRendu
(no matter if the common mode noise is flowing towards or from the microRendu)
B: And the (U)HF noise source. This not necessarily needs to be the Signature PSU.

When trying too draw a circle that closes a loop, it is easy too see this only can be done through:
Circle A: a loop via the USB cable + power cords attached too system parts
Circle B: a loop via the LAN cable + power cords attached too network equipment and systems parts.

Suppose the noise travels back using circle A.

* Bridging the gap.
May be Mercman could also offer an alternative path for the noise too flow along in an attempt to bypass the circuit board inside the microRendu.
He could try too connect a wire between the PSU casing and the microRendu casing. It might work. But also it might not work and even making things worse by creating an extra loop.
All depends on where the noise source is located and if there is also a 'Pin 1'-type of design flaw present in any involved equipment.

* Hunt for another stick on plaster.
Most likely you are right about this.
Because the common mode noise needs an opportunity to get onto a power cord and travel back through the electrical system too the Sonore Signature PSU too close the loop .
Common mode noise on PSU (ref grnd) wire -> (ref. grnd) circuit board microRendo -> (ref. grnd) wire USB cable -> (ref grnd) circuit board DAC -> etc
Somewhere along this route it has to get on a power cord and travel back too the Sonore Signature. It might use the parasitic capacitances between the power line and the equipment ground for this. But it may also exploit yet another design flaw for this.

Mark

 

Indeed: very marked SQ improvement! Thank you for sharing ! (NT), posted on January 27, 2017 at 08:02:28
hfavandepas
 nt

 

Comments on your post (sorry - a bit long), posted on January 27, 2017 at 09:37:32
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 Indeed: very marked SQ improvement!

Thanks for the feedback. Are you using decent cable/plugs? Have you done every possible cable? If not, you may well have further improvements in store. Meanwhile, as promised, comments on your earlier post.

It highlights a 'hidden' problem that I also had in my system

WRT the Juergen Reis interview, I'm not sure you're right to suggest that "these 'back door leakage currents' are also better known as: ground loops". My take was that by "back door noise" he meant how different PSUs in the same system tend to interact with each other in ways that the spec sheets don't (can't) describe even when properly configured that nevertheless degrade the sound. Ground loop issues are well understood even if tackling them can - as you've found - be time consuming.

John Swenson makes a similar point on the Uptone Audio web site - see link. He suggests that:

There are two methods by which a power supply interacts with the AC mains and the difference is not well understood by most people (even many engineers). The solutions to deal with them are very different but get all jumbled up in most peoples minds [snip]:

1) noise between the hot and neutral (and maybe ground wire)
2) leakage current between the AC line and the DC output of a PS

#1 is pretty straight forward and what most people think of when they talk about "noise injected into the mains". There are many types of filters, power conditioners etc that deal with this.

#2 seems to be much harder to understand. It is created by the power supply, some of the AC voltage on the mains sneaks through parasitic capacitances in the PS and winds up on the DC output. The strange thing here is that it is between the the AC line as a whole (hot, neutral, GND) and the DC output as a whole (+, -). It does NOT exist between hot and neutral or between the DC - and +. It is between the two groups.

Because of this any type of normal AC line filter or DC filter or regulator is completely useless at combating this. All these devices work by "filtering" the noise between hot and neutral or between + and -. But this type of noise does not exist that way.

Later, he advises folk to take any filters for "type 1" noise out of their systems and instead connect everything via a multiplug to a single mains socket. I can't comment on how well that works but I can say that the Swenson-designed LPS-1 "Supercap" PSU which I'm currently using to power the DAC end of the fibre optic (and gubbins) link between my system's audio PC and its server transforms (sorry) the SQ of my system.

BTW, every other box in my system except the amp connects to the mains via a Jon Risch-style DIY mains isolator (i.e. the audio PC, an Intona, the USB>I2S board, the DAC and the DAC's I/V section, five devices (ten transformers and 15 coils . . .) all told. A transformer good enough to isolate a power amp is too expensive. I don't know if the isolators are dealing with "back door noise", "Type 2 noise" or just noisy neighbours but I do know that if I take them out there is a dramatic drop in sound quality. I'm hoping soon to get a second LPS-1 for the PC.

I feel pretty sure it's not ground loops I've cured as discussed in the Jim Brown or Bill Whitlock papers as I have no connections between system ground and safety ground. (There are safer ways of keeping them separate BTW so don't take this as a tip even if I got it from a Charles Hansen post a while back.)

Finally, though removing redundant pairs from my LAN cables also makes - as you've confirmed - for a jump in SQ, it is definitely not because it fixes a ground loop issue. LANs use differential pairs that have no ground; LAN sockets always come with an isolating transformer and I have in any case two in-line medical-grade isolators not to mention that pesky ground-free LPS-1 PSU. My guess would be that removing the wires (and running at 10-BaseT) does wonders for Near-End Crosstalk on the spare pairs. But it's a guess. What's not a guess is that it was an effective tweak.

HTH

Dave

 

Steve, maybe this will help, posted on January 27, 2017 at 13:29:35
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002

 

Good one! (nt), posted on January 27, 2017 at 13:44:19
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 .

 

RE: Comments on your post (sorry - a bit long), posted on January 27, 2017 at 21:52:30
Ugly
Audiophile

Posts: 2912
Location: Des Moines, WA
Joined: August 22, 2006
 "I feel pretty sure it's not ground loops I've cured as discussed in the Jim Brown or Bill Whitlock papers as I have no connections between system ground and safety ground."

If I remember correctly the Risch "isolators" are RC filters, right? RC's are for "type 1", aka differential mode, problems.

"Type 2" noise is a subset of the more broad set of problems known as common mode noise.

It's pretty safe to say that in general solutions for differential problems are almost completely useless for common mode issues and vise versa. All systems will have a bit of both differential and common mode noise present pretty much throughout the system. It's only a matter of how much and is it a problem? Many times the most effective solution is a bit of both differential and common mode filtering.

There is only so much that even the best power supply designer can do in design and layout to prevent emi. Mother nature disallows perfection from an emi standpoint. Unfortunately, in some cases, filters are the best option. When all that can be done in these areas has been, you are left with filters to get you the rest of the way. Filters are a necessary evil.

Henry Ott is considered one of the old masters when it comes to understanding EMC issues. Slide 16, in the link about common mode problems from power supplies, gives a visual for the power supply leakage current "ground loop" path from energy transferred via transformer inter winding capacitance and via parasitic capacitance to nearby conductive objects.

As Ott points out, in the slides but also in his several excellent books on the subject, leakage current generally responsible for causing conducted problems. Conducted problems can be handled with filters.

Though an important point to note, by my estimation, is that conducted can easily convert to radiated and vise versa under the proper conditions so getting a filter in just the right location is critical to prevent high frequency conducted problems from converting to radiated energy.

Diff mode problems are easy, you can easily see them with any oscilloscope. With common mode, not so much.

The hard part is figuring out if you have common mode problems big enough to worry about and all it's mechanisms and nature of being. With that info dealing with it is a snap. However, to set yourself up with the necessary gear and knowledge to do well at it is beyond practical for most.

Avoiding problem children at the time of new power supply purchase seems logical to me. But it's not as if the power supply companies I'm aware of are making it easy by supplying emi scan captures or anything useful like that. It's annoying.

After that, most of us are pretty much left trying stuff.

Getting into designing and having success with getting the audio system to sound better via common mode filter application is gonna be tricky for a noob. Getting the current handling capacity, as in power amp filter for example, is easy as getting enough wire gauge for the current. It's getting the filter tuned to and getting enough attenuation at the frequency of noise problem you have, putting the filters in the right spots in the proper orientation is where all the action is.

Since it's tough for us mortals to easily take a look at the problem it's about like shooting in the dark when trying to get the right filter put into the right place.

Some educated guesses are no brainers though in my opinion. For example it's almost guaranteed a PC power supply, even if covered in emi certs, will be injecting some amount of stuff back into the power line as well as onto its other cables. Playing with blocking noise from conducting out of the various cables emanating froma typical PC isn't too risky in my opinion. In fact it seems very popular on this forum now days. Your mileage may vary.

wow guess mine went a bit long too.

 

RE: 'back door leakage currents' = ground loops (very, very looong post), posted on January 27, 2017 at 23:22:30
Bibo01
Audiophile

Posts: 648
Joined: December 18, 2008
 Hi Mark,

Thanks for your post.
Which Epcos power line filter did you put into the ATX PSU power cable?

 

now with added coils . . .), posted on January 28, 2017 at 06:02:13
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 Many times the most effective solution is a bit of both differential and common mode filtering

Thanks for an interesting post and links. I admit that I don't get how the Type 1 / Type 2 distinction or the notion of "back-door noise" adds to what is already well known. It's been several years since I looked at Henry Ott's paper. Who knows? I might get more from it this time . . .

Whatever, JR used isolating transformers because they allow high capacitance across live and neutral without excessive leakage currents (see link). He specified split-bobbin transformers because they were easy to get for a "cheap and cheerful" project and for their low inter-winding capacitance. In practice, they get pretty hot and tend to buzz. Because I had suitable toroids to hand, I used them instead, fitting those with inter-winding screens on the input side. (Don't know why but grounding the screens on both transformers regularly trips the ELCB.)

As you suggest, designing and measuring decent filters seems beyond many audio designers, let alone us hapless DIYers. Once I grasped the importance of clean power for audio, I did much as you said and "tried stuff". After lots of "stuff", much of it discarded, my rules of thumb became:

1. A dedicated power line for digital kit and another for analogue. With care and a bit of luck, both will have lower impedances than the typical home supply (esp with UK-style "ring" circuits) and be relatively free of crud.

2. No cheapo SMPS PSUs on the above. If you need one for e.g. a data server, run it from a separate line and, if possible, connect via the latest fad, optic fibre. (It is a fad but a very effective one if done right.)

3. Instead of JR's high values of C across L&N, fit C-L-C filters between the transformers. I copied a commercial mains-rated design several cuts above those IEC socket things. By using one isolator per line-level device (~15 watts each), no real need for large coils.

Hopefully, unlike JR's circuit, I'm addressing both noise modes and, by using separate isolators & filters for each device, helping to prevent noise from one device affecting another. I don't see how a simple connecting strip or system-wide filter can do that. At least in my system, the difference that several discrete isolators makes is very apparent even though I'm using decent PSUs.

Feel free to criticise.

D

 

Think carefully, posted on January 28, 2017 at 06:11:36
fmak
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Posts: 13158
Location: Kent
Joined: June 1, 2002
 '"Optimising" in the PC audio context means configuring an OS to favour audio reproduction, typically by disabling non-audio-related functions'

I don't know how this type of statement can be made with any degree of authority, when nobody can determine exactly what to disable to achieve what you said. If you go back to CMP (your favourite it seems), disabling certain processes or altering them can make a system sound worse. The whole thing depends on what system is used and what hardware and software it is loaded with.

There are competing software suites that are claimed to optimise audio replay. The fact that they all sound different and the fact that the OS used has an effect mean that there is no optimisation of audio playback. The fact that you can make changes to a USB or LAN cable to affect SQ materially is another obvious argument against so called 'optimised' systems that some claim or imply that are superior to those used by others.

I am not going to argue with you about Dictionary definitions. I am simply saying that it makes no sense for anyone to claim that he/she has an optimised system that is immune to even small hardware, software and setup changes.

 

RE: Think carefully, posted on January 28, 2017 at 07:03:42
Mercman
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Posts: 6581
Location: So. CA
Joined: October 20, 2002
 "I am simply saying that it makes no sense for anyone to claim that he/she has an optimised system that is immune to even small hardware, software and setup changes."

I agree with this. Computer optimization or slimming of the OS does not make the system immune to other changes. I honestly don't remember ever implying this for myself.

 

RE: Think carefully, posted on January 28, 2017 at 07:20:32
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 I don't think of you as a claimant, but you have used the term loosely and so can imply it.

However, others have made claims that point to the 'superiority' of their 'optimised' systems which contain obvious non-optimised features.

I have raised these points repeatedly because the claims do mislead inmates and more recent computer audio adaopters.

 

Additional Resources, posted on January 28, 2017 at 09:45:06
AbeCollins
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Posts: 46280
Location: USA
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Contributor
  Since: February 2, 2002
 ...including the two Henry Ott books in my collection. "Noise Reduction Techniques in Electronic Systems" has been a go-to reference since the 1980's.




 

RE: now with added coils . . .), posted on January 28, 2017 at 12:48:43
Ugly
Audiophile

Posts: 2912
Location: Des Moines, WA
Joined: August 22, 2006
 It sounds like you are already using a tuned 2 stage line filter with common mode filter first stage and differential mode filter second stage. That sounds like a really good starting place for trying out in various locations.

Not that you didn't already think of it or maybe already even doing this but since you didn't mention it a couple potential tweaks for tuning the common mode performance of the first stage come to mind.

Maybe running the CLC in a balanced differential CLC configuration with respect to live and neutral will help enhance common mode rejection performance of the first stage without sacrificing the second stages differential mode performance. Ie you'd still have the same X caps spanning line and neutral but the balanced configuration would have an a separate L (but half the L as compared to an equivalent single ended version of the filter) between the caps on both the line and neutral.

You could also try adding, in a balanced manner, 2 identical and appropriately rated Y caps. One from from live to earth and one from neutral to earth. I'd try variations on where they belong, ie on the transformer primaries, transformer secondaries, after the CLC??? Some where around around 1nF ought not put you up against code violation most locales and is probably a fair place to start experimenting. Adding the Y's like this is to try and enhance common mode noise rejection of the first stage.

The only other thing I might add is that remembering to swap the order of the stages with respect to source and load to see which way works better during experimentation is another thing that may very well be worthwhile.

Edit: maybe there is a use for a damping resistor from line to neutral after the CLC to enhance it's performance.

 

A quick google search..., posted on January 28, 2017 at 19:52:23
Presto
Audiophile

Posts: 5957
Location: Canada
Joined: November 10, 2004
 And I found this site which references Jim Brown and many other sources. Now I have much reading to do, and much investigation into some of the gear I own.

Thanks for posting this.

Regards,
Presto

 

Also..., posted on January 28, 2017 at 20:01:18
Presto
Audiophile

Posts: 5957
Location: Canada
Joined: November 10, 2004
 Rane Note 110 - Sound system interconnection guide.

Priceless.

 

RE: now with added coils . . .), posted on January 29, 2017 at 03:34:01
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 You could also try adding, in a balanced manner, 2 identical and appropriately rated Y caps

Thanks again for your reply. I did ponder doing as you suggest but decided I was perhaps making things a bit over-complex what with five (hopefully) separate devices. I've also got the units buried out of sight and difficult to get to. The temptation to fiddle is reduced but I might just experiment with a spare.

maybe running the CLC in a balanced differential CLC configuration with respect to live and neutral will help enhance common mode rejection performance

H/W the circuit though I didn't fit the 0v link or the 1M resistors.



Because there's a 240V > 24V transformer on the input, the filters are working at low voltage. I didn't see rating as a worry and used a pack of cheap Y-rated 220nF caps. (I'm aware that some places would need X-rated caps were they at mains potential.)

OTOH, currents are higher at the lower voltages even if no isolator is in practice passing more than about 3/4 of an amp. I guessed that 3-amp-rated Murata coils with DC resistance 0.03R would be fine. Well, they're not getting hot . . .

maybe there is a use for a damping resistor from line to neutral after the CLC to enhance it's performance

Agreed but I didn't feel confident in calculating a value so I left them out. Again, I could experiment.

D

 

RE: Comments on your post (sorry - a bit long), posted on January 30, 2017 at 01:14:29
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 that one cannot 'optimise' a system through conjecture. When optimising in the technical sense, the cause and effect of each variable is generally understood and optimisation involves the give-and-take in terms of achieving a final result.

When you talk about OS optimisation, the precise effects of many elements of the OS on audio replay quality are not known and so called 'optimisation' is based on conjecture, often speculative ones at that.

So if you say that your system is 'optimised', then you would have had to understand and install power supplies that are 'optimal'. Otherwise, if you make a small change to these and get a material change in SQ, what does 'optimisation' mean? Similarly you LAN cable and other peripherals.

Power supply interactions are complex and using two transformers back to back to provide optimal isolation' is conjecture. You are altering the source impedance significantly and it can be that you are hearing an improvement because something else in your system is 'not right'. As long as you accept that this outcome is fine (optimal for you) and do not pontificate on pseudo technical reasoning for others to follow, then this is fine by me.

As an aside, I know for a fact that, apart from filtering and current leakages, the effect of mains frequency can cause strong changes in SQ (my preferred regenerator frequency into my dac being 73 Hz ???????). As I said above, I simply have to accept that this is so for my system without dwelling into the technology and pretending that I know better than others.

As for isolation transformers, there is no substitute for spending the necessary money to buy units deigned as such and if possible have technical data to back them up.

There are transformer manufacturers who know what they are doing and can supply units to requirement at reasonable cost.

 

RE: Comments on your post (sorry - a bit long), posted on January 30, 2017 at 03:49:45
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 that one cannot 'optimise' a system through conjecture.

Some copy missing?

When optimising in the technical sense, the cause and effect of each variable is generally understood and optimisation involves the give-and-take in terms of achieving a final result.

Sounds good but not sure it's relevant here.

When you talk about OS optimisation,

I don't talk about OS optimisation - see above.

the precise effects of many elements of the OS on audio replay quality are not known and so called 'optimisation' is based on conjecture, often speculative ones at that.

Nonsense. Many OS functions have no role in the audio replay chain. Though it can be tedious, disabling or deleting them is generally trivial and has been done to varying degrees across the audio sector for over a decade. Something tells me you've not tried it even if you do experiment with this and that.

So if you say that your system is 'optimised'

Sigh. I don't use the word 'optimise' but neither do I feel the need repeatedly to belittle those who do with gobbledegook about power supplies.

then you would have had to understand and install power supplies that are 'optimal'. Otherwise, if you make a small change to these and get a material change in SQ, what does 'optimisation' mean? Similarly you LAN cable and other peripherals.

Again, nonsense. If, say, I disable enumeration in the USB stack, I definitely lose flexibility and may or may not get better SQ but PS quality has nothing to do with it. If you want to call snipping a couple of pairs from a LAN cable 'optimising' it, who am I to stop you?

Power supply interactions are complex and using two transformers back to back to provide optimal isolation' is conjecture.

You've changed the subject and accused me of saying "optimal'. Again.

You are altering the source impedance significantly and it can be that you are hearing an improvement because something else in your system is 'not right'. As long as you accept that this outcome is fine (optimal for you) and do not pontificate on pseudo technical reasoning for others to follow, then this is fine by me.

Now you're the one who's guessing. Of course the setup raises source impedance which is why one and all stress that it isn't suitable for dynamic loads. We're discussing powering devices that present a low and more-or-less constant load well within the transformers' power rating. You seem also to miss the point that we're talking about isolation and filtration with an eye on leakage currents.

As I said above, I simply have to accept that this is so for my system without dwelling into the technology and pretending that I know better than others.

But almost every post you make has you pretending you know better than others though not always convincingly.

As for isolation transformers, there is no substitute for spending the necessary money to buy units deigned as such and if possible have technical data to back them up. There are transformer manufacturers who know what they are doing and can supply units to requirement at reasonable cost.

I know of a couple of UK manufacrurers who sell reportedly excellent audio-grade isolation transformers but they are not cheap. They're too expensive for me and, in any case, overkill for circuits drawing ten watts or less. Among the "stuff" I tried were ordinary isolation transformers from reputable suppliers but they didn't impress.

 

specs Epcos EMC Filters Series/Type: B84111A, posted on January 30, 2017 at 05:11:06
hfavandepas
 Hi BiBo01,

I use these Epcos filters because the are readily available and not very expensive.
But many others company's manufacture same types.

Epcos EMC Filters Series/Type: B84111A
See http://www.mouser.com/ds/2/400/b84111a-773410.pdf
(Since 2013 Epcos stopt production.)

On the ATX PSU power line I put a filter which can handle 3A amps.

2 years ago I still used active Klein & Hummel O300 monitors which have 3 amplifiers build inside with a total max consumption of 435 Watts per speaker. Sow on the power lines too the K&H O300 I put an Epcos (6A amps rating) reversed (line side now is: side with the caps)

You find the schematic's all over the www and they are used by many other filter company's like Schurter, etc.
I first saw the schematic's discussed in Ivor Catt e.a. book Digital Hardware Design, by Ivor Catt, David Walton, Malcolm Davidson.
http://www.ivorcatt.org/digital-hardware-design.htm
Chapter 14 page 84 and on.

The Epcos filters I use have a standard, generic design which does not filter the ground-wire.
So depending on where the noise source is located, the ground-wire may still facilitate loops.

Mark

 

Obvious Contradictions in Your Posts, posted on January 30, 2017 at 05:51:27
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 ''I don't talk about OS optimisation'' Quote 1 from you

''"Optimising" in the PC audio context means configuring an OS to favour audio reproduction, typically by disabling non-audio-related function.''
Quote 2 - from you http://www.audioasylum.com/forums/pcaudio/messages/16/162783.html

So, what are you on about?

It is no good quoting bits of what I said and responding in bits and pieces. You need to make cogent arguments if you wish to discuss. After all, you invited criticisms of your post and now it seems that you cannot take comments seriously.

 

RE: Obvious Contradictions in Your Posts, posted on January 30, 2017 at 06:24:35
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 So, what are you on about?

You have a bee in your bonnet about and sounded off on the word 'optimise' so I explained the sense in which other people use it in our context even though I don't use it myself. I don't see what's difficult about that.

The link you provide with that conjuror's flourish confirms that. I wrote: "It may, as you argue, be a misuse of the term but the rest of us know what it means even if I prefer to say "slimming".

You need to make cogent arguments if you wish to discuss.

You miss the point - I really, really don't wish to discuss with you but, as you were talking nonsense about 'optimisation' and more nonsense about Jon's little circuit, I felt obliged to correct the record.

I should've let it go . . .

D

 

RE: From another thread..., posted on January 30, 2017 at 07:02:04
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
 Hi there.

To me at least it's not new that cutting certain pairs made a difference.
I think we discussed it around 5 years back.

I recently cut a broken rather long Meicord into pieces and terminated these also with Telegaernter MP8s. The MP8s are quite nice.

I didn't run any ethernet cable comparisons lately.

***

And nowadays I run GBIT LAN on my PI3. Actually I achieve 300MBit/s with a 10Euro USB3 ethernet dongle which comes with potentially better ethernet chip. The handling became much snappier and my files are loaded much faster into RAM.

I also applied an idle sitting AQ Jitterbug to that ethernet dongle for having some filtering in place.

And. Since I had some of Sbooster filters around, I hooked these up
to my Cisco ethernet-hub which sits right next to my Pi and to my FritzBox power supplies on the other end.

All that sounds extremely clean to me.


I'm wondering if LAN isolators are worth it -- if you go the UTP route.
I heard stories that people didn't notice any differences. That's why I left it alone.

I didn't jump on the fiber train, since the known devices have no hubs at the end.



All that - A never ending story.

Enjoy.



-----------------------------------------------------------------

blog latest >> The Audio Streaming Series - tuning kit pCP

 

Separate post for your very effective LAN tweak?, posted on January 30, 2017 at 08:08:58
hfavandepas
 Hi Ryelands,

Friday evening I hurried of too a friend too show him your LAN tweak. And also in his system it gave a very marked SQ improvement. Even bigger as in my system.

I use these brandless OEM connectors
EAN productcode 8716065132205
See:
https://intronics.nl/en/product/keystone-and-modulaire-connectoren/modular-connectors/intronics-oem-rj45-8p-8c-modulaire-connector-for-round-cable-with-solid-conductors-td108m-

I buy these and the UTP-cable at https://www.netwerkwinkel.com

I have not done every possible cat 5e cable. For the experiment I only modified a 1,5 meter UTP cat 5e cable that sits between the Baaske LAN cable isolator and the MAC mini build-inn LAN socket. I only modified the RJ45 connecter that connects too the MAC mini LAN-socket.

Between the Merging Hapi LAN socket and the Thunderbolt LAN Adapter a LAN cat 6 cable is used that came with the Merging Hapi. I did not modify connectors on this cable.

From the Baaske LAN isolator there is about 20 meter of UTP cat 5e cable traveling through floors, walls and ceilings too the breaker panel closet. In the breaker panel closet I keep the rest of my internet equipment (cable modem/router/switch box, managed Netgear Prosafe switch, Synology DS216 NAS, D-link DIR 868-L WiFi-access point, Philips Hue bridge).

At what more locations in your wired LAN network did you also changed the connections in the RJ45 plugs?

My be I put aside Juergen Reis too quickly as just another manufacturer of highly overpriced 'High Futility Audiophool' gear. He after all also said (16:11 min) "when every thing is connected balanced than the influence of the cable is really shrinking", "too a minimum". Most HiFi manufacturers would rather die first, than admitting the need of such basic, best practice.

I looked again at the video and Juergen Reis points at 'capacitive coupling' as being part of the loop. Capacitive coupling bridges the gap and creates/closes a loop. But what exactly is the noise source (driving force), stills stays unclear too me. Same for John Swenson's text. I do believe him on his word that "some of the AC voltage on the mains sneaks through parasitic capacitances in the PS and winds up on the DC output". I wished John had taken more time not only too point at that there is a the leakage pathway from AC-side too DC-side in the PSU, but that John also would have explained how the source (driving force) is created and how the noise loop is closed (in most systems).

The above mechanism may be the same as on Page 16 in the PDF with Ugly showed too us. Just speculating.
http://www.hottconsultants.com/pdf_files/APEC-2002.pdf

"and instead connect everything via a multiplug to a single mains socket"
This is the oldest remedy I know. This was how I became aware of having a huge ground loop in my system. I temporary connected my system via a multiplug in a single mains socket because my living room needed fresh painting. This unmistakably sounded better. Which made me realize, I had a ground loop in my original setup for years.

Would you consider posting this effective tweak as a separate post?
Your effective tweak is now hidden as an off-topic subject in Mercman's post.
Not many inmates will find this magnificent tweak here in this post !

Mark

 

RE: From another thread..., posted on January 30, 2017 at 08:13:31
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 To me at least it's not new that cutting certain pairs made a difference.

Interesting - thanks for the feedback and for the RJ45>USB idea.

I didn't do any structured LAN cable comparisons, just played about with what I had to hand and pinched other folks' ideas. The Telegartner tip came from the CA forum; I genuniely thought the snippie bit was my idea but maybe I saw it somewhere. Who cares? It seems to work.

I'm wondering if LAN isolators are worth it if you go the UTP route. I heard stories that people didn't notice any differences.

I certainly hear the difference even with vasectomied LAN cables and an LPS-1. I use two, one either side of a pair of hubs sited after the media converter. I'd love to use them elsewhere but the loss of SQ is immediately apparent. H/W Quickie Piccie of the setup (moved to a desk, not on its rack).



I didn't jump on the fiber train, since the known devices have no hubs . . .

For me, the sound is definitely better with the fibre link, Zytek hubs and EMO isolators though the latter probably make less difference than the hubs. The LPS-1 was a big step up from linear PSUs.

If you were to say "you're mad", I'd probably agree. If you were then to say "there must be an easier way to do it", I'd definitely agree but, so far, I've not found it.

In any case, there comes a point where you write off the cost and effort and just play music while reminding oneself that the setup cost less than many fancy LAN cables and would, I suspect, do well in comparison.

Just wait till I've optimised it . . .

D

 

RE: now with added coils . . .), posted on January 30, 2017 at 14:15:47
Ugly
Audiophile

Posts: 2912
Location: Des Moines, WA
Joined: August 22, 2006

I enjoy chatting about this stuff. No need for thanks here. I appreciate your sharing your secrets so I can see how much I'd like to try myself.

Imagine your transformer in place of the common mode choke...This is what I was envisioning Note the Y caps orientation with respect to earth. It might be worth playing with to try and increase impedance to common mode noise.

Though, regarding your filter schematic, I haven't seen anybody using an inductor on earth that way leading me to wonder what it's function in the circuit is. Presumably it can't do much until there is appreciable earth current which in my locale is strictly forbidden above a tiny level.

With double insulated, tinyish transformers, even the authorities presumably wouldn't have any problem with you not using special safety rated parts.

 

the rest of us , posted on January 30, 2017 at 16:24:23
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 Ho! You mean you with YOUR definition.

 

the rest of us get it..., posted on January 30, 2017 at 17:31:30
AbeCollins
Audiophile

Posts: 46280
Location: USA
Joined: June 22, 2001
Contributor
  Since: February 2, 2002
...but you appear to have a comprehension issue, again.


 

RE: From another thread..., posted on January 31, 2017 at 01:24:23
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
 Your cable looks like mine. I did put a nice black jacket on to make it look serious, audiophile and - most important - pricey. ;)

I do find your DC wires quite a bit "exposed".


And you just use the 100MBIT fiber. OhhKaay.

I do agree. The HUB itself makes quite a difference.
I mean a HUB "reclocks, regenerates, rebalances, refilters, rebuffers, resignals, re...whatsoever" the stream.
(Thorsten are u listening??? The world needs an iNurifier (N for network) ;) )

****

These EMU filters just cut the ground/shield. That you'll have with a UTP cable. Or u just don't connect the shield to the MP8.
And the EMU will cope with surges/spikes. What more at 129$?

As explained on the Meicord page. The jacks/plugs do cause trouble on their own. You introduce two more of them with the filter in place. Hmmh.

Nope. I won't even try one of these devices.

****

I'm not a fan of the LPS-1 for several reasons.

1. It's much too weak.
2. It doesn't really act like a battery with the LDO at its output.
3. I do also consider that LDO overkill inside a pre-regulation stage
4. People don't actually know what's causing the experienced improvements!
Sometimes just reviewing and rearranging your grounding scheme does more then a DAC upgrade or a new PS.
5. I really like your heatsink on top of it.
6. Let's not talk about the price.


Enjoy.


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Trolling on, posted on January 31, 2017 at 02:47:36
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 issue you have invented again.

 

RE: From another thread..., posted on January 31, 2017 at 04:54:14
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 I did put a nice black jacket on to make it look serious, audiophile and - most important - pricey. ;).

Ah. I removed a nice lilac-coloured jacket from the smaller leads so I could make shorter connections with tighter bends. The audio-macho look came with. NB that the pairs are slightly separated and cross at right angles. You could be right about the DC wiring but then you didn't see the first hookup . . . what would you suggest?

The 10/100MBit media converters are half the price of faster ones. The Zytek switches (as recommended on a CA thread) are also 10/100MBit only and do actually sound slightly better than the little gigabit Netgear boxes I used while experimenting. They cost slightly more so they must be better.

I agree that the LPS-1 is expensive given its low output (< 1.2 amps) but supercapacitors are an emerging technology at least in audio. They are IMHO a significant breakthrough whatever their weaknesses.

Sometimes just reviewing and rearranging your grounding scheme does more than a DAC upgrade or a new PS.

The setup shown in the pic (and, of course, the other end) took me several months to get 'right' but was such an improvement sonically over the Netgear/linear PS as suggested on your blog a few years back that I still can't quite believe it.

Yes, easily as good as a new DAC. Moving data from a remote server over optic fibre can work very well but what I learned was that you do have to do it right. Skip the regen razzamataz and you are likely to be disappointed.

++++
These EMU filters just cut the ground/shield. That you'll have with a UTP cable. Or u just don't connect the shield to the MP8. And the EMU will cope with surges/spikes.

Not so - see datasheet. They decouple data pairs with transformers as well as cut any shield. They were designed for the medical sector where lawyers seem to like protecting patients from the mains. The Baaske may also use transformers - I don't know - but the EMOs definitely do. Whether they're worth the money is a fair question (I bought mine well before I got into the fibre thing) but I know that the difference they make is readily audible even in UTP links.

As explained on the Meicord page. The jacks/plugs do cause trouble on their own. You introduce two more of them with the filter in place

I'm not sure that that's what the Meicord papers say. See also the BJ link. Both suggest that few LAN cables come even close to spec and that the biggest problem is typically the plugs. They don't seem to claim that connectors inevitably degrade the signal to below spec, only that designing quality plugs is not trivial. Obviously, any plug degrades to a degree but the suggestion that they do so to an extent that inevitably makes in-line filters useless is not supported by data or, in my case, experience.

I tried a couple of the Telegartner connectors with Excel cable and found they sounded as good as the Meicord products or, post-vasectomy, better. Both are way better than Amazonic stock but a one-metre Telegartner/Excel cable still only costs about $10, the Meicord about ten times that.

BTW, AQ LAN cables use Telegartner plugs with, I suspect, a small markup. IME, no need for screened Telegartner plugs. Both types work fine on UTP but the screened, though slightly more robust, are harder to rework.

 

RE: From another thread..., posted on January 31, 2017 at 07:21:54
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
We compared supercaps with other quality caps.
I can't confirm that these are superior in general.
It depends on the application.
They IMO work better without that LDO behind it.
Then you also won't suffer power limitations.


Each ethernet jack has a decoupling transformer inside!!
They are all isolated.

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RE: From another thread..., posted on January 31, 2017 at 08:16:06
Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009
 We compared supercaps with other quality caps.

"We" being? Any details, links?

Each ethernet jack has a decoupling transformer inside!!

Is that right? And there was me thinking that the regs for medical equipment might just be a bit more stringent than those for consumer kit. Silly me.

So the differences I hear are all in my imagination? Funny old stuff, psychology.

D

 

RE: From another thread..., posted on January 31, 2017 at 12:45:00
soundchekk
Audiophile

Posts: 2426
Joined: July 11, 2007
 We did some tests at a friends place.

"So the differences I hear are all in my imagination"

Not at all. You change the physics. You change the sound.



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blog latest >> The Audio Streaming Series - tuning kit pCP

 

Just wait till I've optimised it . . . , posted on February 1, 2017 at 18:05:17
fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002
 From the inmate who 'doesn't' talk optimisation!

 

I agree, posted on February 3, 2017 at 05:29:07
Mercman
Audiophile

Posts: 6581
Location: So. CA
Joined: October 20, 2002
 Dave has done something that deserves its own post.

 

Nice read!, posted on February 3, 2017 at 08:08:08
E-Stat
Audiophile

Posts: 37584
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 I used balanced connections in the main system. In the HT, I once needed to use one of the Jensen isolators on the incoming cable signal to tame a nasty ground loop.

 

As I observed before..., posted on February 4, 2017 at 06:51:58
E-Stat
Audiophile

Posts: 37584
Joined: May 12, 2000
Contributor
  Since: April 5, 2002
 like a friend of mine, the fmakster "doesn't hold the {fill in the blank} dictionary as any authority" when using language. :)

 

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