Overall Isolation - network, USB, and power

[One and a half]

With so many small DC power supplies powering far too many components, the chances for ground loops are very high. I see a few USB connections between the Recovery and the Aries which gives me the shivers. Try and connect as many as possible from the one PSU and avoid mutliple power supplies wherever possible. Sadly, each manufacturer goes their own way and there's different voltages for everything...omg a real dog's breakfast.

 

Don't count on the PSAudio device to give you AC isolation and the AC will be the last place you get noise from. I would wait for the LPS-1 to arrive and incorporate it wholesale or figure out a less cable intensive system with less devices in the chain. For example, the Focusrite D16R system would be the way to go with the advantage of Ethernet to AES3 direct and then to the DAC, far simpler, and still streaming with isolation. Can still use the FO media converters, but use the same ones and T off the one unit.

[One and a half]

That is what I was thinking, by adding an LPS with multiple taps like the HDPlex. But even that is a minefield. Some have advised against that, especially when it spans an isolation boundary. I am still awaiting a good explanation for that rationale.

 

I'm deterred by the cost of the LPS-1, but I agree it looks fantastic.

 

I sympathize with your advice to bypass USB and use AES, but sadly both the Aries Mini and the Codex don't support AES, and claim to work best with USB.

 

Just a snip here and there to reduce the overload of the repair by breaking it down in parts.

 

The ideal is one large power supply to drive all devices. The reason for that is, the ground plane is the same. The resultant current from the AC is the sum of all secondaries, plus losses in the transformer stage. hold this though for a second. If you have different voltages from the same source, imagine a large DC supply, some 15Vdc 6A something and multiple regulator circuits for 12V, 9V, 6V etc. You still have the advantage of the same DC source, but the return ground planes will be different, since they will have different return currents. The end result is a mush of currents in the DC source. Hence the reason for creating the LPS-1. For the LPS-1, all supplies are isolated from each other, so you could still have a large DC source and a cavalcade of LPS-1 and complete isolation, yay!

 

High level harmonics reduction - Not tried yet for audio

You 'could' do something really special with the transformer's secondaries, so that each downstream power supply sees a secondary winding with a displacement. The displacement winding is offset from the primary by something other than 180 Degrees. It can be 30 or 60 degrees. The trick is to have another secondary winding displaced at the same angle but retarded, like -30 degrees to the +30 degrees. The net effect of any out of balance currents, especially the noisy shite, will 'dissolve' (as heat). This will only work if the load currents are the same. Given the loads may vary, and our voltages are different, such a transformer is an idea, but not a very practical one for small loads.

 

Other than battery supplies, or a wholesale LPS-1, the ground loops will still be there. So other than a technical solution, it becomes a commercial and philosophical decision also. Like most of us, we evolve our audio systems and keep on building and fixing things, until the number of tweaks get out of hand and cause us more problems than we can solve.

 

I've completed this recently this week, with removing USB as the transmission from audio. USB worked for a while, but there's always fiddling, and far too many devices and connections in the way, so had enough. Returned the RME AIO sound card to service and AES3 is sourced from the computer to the DAC, straight through 2 x MC-3+USB reclockers. PCM never sounded so good.

[One and a half]

I wonder if it would have been better for the generated AC to be low-pass filtered, e.g. with choke, before being fed to the isolation transformer. The design may be counting on the transformer to act as a low-pass filter to some degree, but depending on the transformer characteristics the filtering effectiveness may be very limited.

 

Perhaps a next-gen Intona design can take a hint from the fabulous UpTone JS-2 linear power supply...

 

From what I have noticed on large UPS (>10kVA) is the inverter (nee regenerator) section is usually driven by a standard PWM system. It's possible to use this waveform to drive AC loads, and UPS are designed like this. With more money of course, the fairly rough output, is LC filtered, sometimes a special transformer that acts as a filter as well can be designed. The better designs use Litz wire formed into an inductor, the caps are metal films. The LC acts to convert the crappy PWM output into a sine wave with reasonably low distortion. You don't end up with the fluxing problems of a transformer, and it's possible to extend your filtering to higher frequencies, mainly to clobber the rubbish from the left overs on the PWM waveform.

 

So the L is more or less smoothing out rapid rises in current, like from diodes, but the L has to be sized the correctly to smooth out the lumpy bits and not be a heater either that impedes real current delivery where it's wanted.

 

The load of course will present its own garbage on the system back to the inverter and we aren't usually better off, depends on the design of the loads. The best way is to isolate at the smaller end of town the paths were leakage current cause problems.

[One and a half]

Well the next big jump your system is going to take is when you receive the UltraCap LPS-1 you have on order. Use it for your W4S Recovery.

 

I'm not sure which version austinpop has of the Recovery, the newer models use a 9V supply. The best the LPS-1 can do is 7V, 22% down on nominal a fair ask. Two LPS-1 are needed, say 5V + 3.3v, that's 7% under, should work OK.

[One and a half]

@One and a half

 

I have the latest Rev B, which can operate on 6-9V/1A. In fact, I have had email exchanges with Tony Holt at W4S, who's confirmed 7V/1A is an excellent operating point to run at.

 

That's excellent news, saving another lps-1 is also healthier wallet.

[One and a half]

The isolation transformer on the AC does a great job of hitting the common mode noise on the head, but it raises another problem!

 

The leaks to earth/ground are not seen by the upstream GFCI/RCD, so another GFCI is required on the output of the isoaltion transformer. A picture speaks a thousand words.

 

 

 

The 6A current is just another load on the first GFCI and it's balanced, so it won't trip

 

Found this great pdf from NEMA about how GFCIs work. They are 'usually' passive devices, that is, they don't create more noise!

NEMA-GFCI-2012-Field-Representative-Presentation.pdf

[One and a half]

USB galvanic isolation and signal conditioning (a la REGEN) are already built into the microRendu design.

Apart from the isolation properties of the hub chip in the regen/microrendu which is very low, I don't recall a claim for USB galvanic isolation. This circuitry is quite complex, takes up more room than the microrendu itself, the conclusion is neither the microrendu/regen have this capability.

[One and a half]

snip

 

But the more I think about this, the more I come back to the fact that the rubber meets the road only at the DAC. That is where the effect of all this isolation matters - in the resulting analog output of the DAC. So, with USB isolation - GI (with Intona), integrity (with Regen or RUR), and leakage loop breakage (with LPS-1) - in place just upstream of the DAC, this begs the question:

 

[/i]I stress that last phrase because I want to clarify that many people - myself included - have heard startling improvements with network isolation. What I would like to know, though, is whether these differences continue to exist if you also have full USB isolation (the Intona/RUR/LPS-1 trifecta or equivalent) downstream.

 

Food for thought. As has been pointed out, so much of what we're hearing from these isolation optimizations do not have a good explanation.

 

This is also my question. Provided the DAC is 'isolated' (more on this later) at one point, then there is no need to isolate further upstream, like in networks.

 

The solutions for isolation on USB are either the Intona or something else in the future that fixes signal integrity as well.

 

If the DAC can be powered within the LPS-1 specs, then use that method, in addition to the USB treatment (Intona/RUR/Regen).

 

For isolation on the AC mains is a little harder, since an isolation transformer can cut out common mode noise, but lower end harmonics, conducted emissions (to a degree) at RF levels require separate treatment. It also depends how much the DAC will keep out the AC line noise, so adding extra bits on the outside will not make much difference and could even make things worse (especially at the RF front).

 

Further if you provide a difficult path for leakage currents in one area, they will find better opportunities elsewhere.

 

Complex subject but dialog helps.

[One and a half]

@fob69

 

I like the approach here. The batteries charge overnight and have enough reserve to cater for the regulator's very low drop out figure. Yup complete isolation from the mains! Superdad may not like batteries and ifi say their power supply is quieter than a 9V battery, but what noise does a battery make? Surely no emitted RF? AM radios would not work at all!!

 

Can you report back on a simple test? Could you place an AM radio close to the charger and does the radio pick up any noise from the battery box when not plugged into the load and not charging either.

[One and a half]

My friend and I tried using a 50' Cat5e cable between wireless router and Aries Femto, bypassing the wireless bridge. It did not sound as good as using the wireless bridge. We actually tried this twice. First time was over a year ago when my friend got his Aries Femto, being an initial trial setup, then again a couple of months ago. The first outcome last year was that wireless sounded better than wired (w/ 50' cable) for Aries Femto. We recently wanted to see if that is still true so tried again, and wired still sounded worse than wireless 5G with one 5G radio of the wireless dedicated to Aries. This means an un-tweaked wired connection is nowhere as good as what Ethernet can ultimately deliver for Aries. The current level of SQ was reached with wireless bridge <> FS105v3 switch (w/ modified Teradak X1/X2 LPS) <> EN-70HD isolator <> Aries setup, using Ethernet Cat5e cables 5' or longer in length.

 

Based on this, my friend and I believe that including wireless within the networking connection between music server and Aries is not detrimental to SQ, and Aries delivers the best SQ when receiving the audio stream over 100Mbps Ethernet.

 

Was the 50' cable unshielded?

[One and a half]

To kick off on another topic of isolation. it is known that SMPS create high impedance leakage currents, and are difficult to remove. Grounding the 0V is one cure, but what of devices like switches, fitting them with linear supplies helps, but this radio amateur found an effective method to block RF noise for his VHF transmission system, was to use large mother ferrites on the Ethernet cables.

Before and after RF has reduction. I thought RF wouldn't affect audio since we are down there in the frequency band, but that RF hash can be converted to conducted noise, so metal boxes may not be the answer.

 

Here's the page, worth looking at. Now this is cheap IT equipment causing RF problem with VHF!!

 

Before

 

After

[One and a half]

3 hours ago, Cornan said:

 

Interesting! I wonder if not the JSSG (farraday sleeves a la John Swenson) that I use on my Ghent ET02 ethernet cables are not doing the very same thing as the ferrite cores? I can tell you that those made a nice improvement. I wonder if I should try a ferrite clamp o each plug end as well to see if that make a noticable difference or not? There is ferrite absorbing sheets around as well that could be interesting to use for covering the plugs. Hmmm? 

I have seen that ferrite cores have been used before to improve ethernet speed. High speed= low RF noise? 

On the other hand ferrites on USB are really bad, they screw up the waveform. 

 

Have a look how many turns the author used on Ethernet cables to reduce the noise.

Im trying to understand at which point where the noise is transmitted, if it was just a single point, the noise would weaken the further away the victim is. In this case the cables conduct the noise freely throughout the house. So maybe the switches are to blame, propagating noise. 

 

Our cousins in the ham radio world despise noise just as much as we do, we have to look closer at their solutions, there’s valuable information we can use.

[One and a half]

17 minutes ago, Em2016 said:

 

A different viewpoint from Rob Watts, on ferrites used with USB cables:

 

"What USB cables are best?

So what are the best USB cables? Firstly, be careful. A lot of audiophile USB cables actually increase RF noise and make it sound brighter, and superficially impressive - but this is just distortion brightening things up. Go for USB cables that have ferrites in the cable is a good idea - it may also solve any RF issues from the mobile that you may have too."
 

https://www.head-fi.org/threads/chord-electronics-dave.766517/page-94#post-12262339

 

Many years ago, when CA was a little child,  Kimber produced a USB cable with ferrites,  it was a disaster. Most of the time, there was nothing, or at worst horrible clicks mixed with music.

 

Totally agree that USB cables can and do sound different, and the RF noise makes the music brighter, but! The noise seriously screws with imaging and once the symptoms are known, the cure is to change the USB chain to suit. To date, this is difficult to achieve and takes a lot of experimentation.