ISO REGEN Listening Impressions (kicked off with some measurements)

[Superdad]

9 minutes ago, Excommunication said:

This is a keeper, as the last dealbreaker is gone, if this good performance continues.

 

Hey, that's great!  Hope you continue to enjoy the ISO REGEN in your music system.  Just let us know if we can be of further assistance at any time.

 

--Alex C.

[sdube]

1 hour ago, Excommunication said:

Unbelievable. I set the Roon playing first overnight, then when I left for work at 7:00 this morning I started a files playlist (not to interrupt my daily Tidal-access from work). I come home almost 15 hours later and the music is still playing (simultaneously breaking in my Mutec and Mogami XLR). I hope I will get my additional USPCB soon. This is a keeper, as the last dealbreaker is gone, if this good performance continues. simonp thanks for the tip, not that my cotton ears will hear that difference with switching sides with the cable, but I want to enhance to the point wherever (others hear differences) possible, and then one day I look back and notice the difference.

So, what is the cable/UPSCB set up you have between the different devices now? Thanks.

[Excommunication]

My original setup microRendu --> QED Reference USB --> ISO REGEN --> USPCB --> MUTEC, since I wanted shortest path to the MUTEC. The testing I did switched places on USPCB and the QED Reference USB, giving microRendu --> USPCB --> ISO REGEN --> QED Reference USB --> MUTEC, hence a very short distance between microRendu and the ISO REGEN.

 

Truth be told I have a Audioquest Jitterbug attached to USB-cable/PCB, but previously I removed it with no success in the first set-up.

[sdube]

23 minutes ago, Excommunication said:

My original setup microRendu --> QED Reference USB --> ISO REGEN --> USPCB --> MUTEC, since I wanted shortest path to the MUTEC. The testing I did switched places on USPCB and the QED Reference USB, giving microRendu --> USPCB --> ISO REGEN --> QED Reference USB --> MUTEC, hence a very short distance between microRendu and the ISO REGEN.

 

Truth be told I have a Audioquest Jitterbug attached to USB-cable/PCB, but previously I removed it with no success in the first set-up.

Thanks for the response. Just maybe the problem is with the USPCB between the ISO Regen and the DAC. At any rate, that is when my troubles began, when I replaced a short Curios cable with the USPBCB between the ISO Regen and  the Berkeley Alpha USb (converter). And the problem has persisted whether I have used a Curios USB 1m or a LH Light Speed 10 or a USPCB now between my Mac Mini and the ISO Regen. With grounding the output of the USPCB on the ISO Regen before the Berkeley Alpha USB, at the moment I have only very rare dropouts and the SQ is super, but perhaps I do need to try a cable rather than the USPCB in this location. So, I would like to know your experience with two USPCBs in a row (whether or not with Silver Bells, And Cockle Shells ..) 

[Excommunication]

9 minutes ago, sdube said:

So, I would like to know your experience with two USPCBs in a row (whether or not with Silver Bells, And Cockle Shells ..) 

You just gave me an idea to switch out the USPCB entirely and add my Nordost Blue Heaven. I did that 3 minutes ago and likewise the music plays, and mR was found effortlessly. We might have pin pointed the problem in this instance, ie the USPCB between the ISO REGEN and the DAC.

[Superdad]

19 minutes ago, Excommunication said:

You just gave me an idea to switch out the USPCB entirely and add my Nordost Blue Heaven. I did that 3 minutes ago and likewise the music plays, and mR was found effortlessly. We might have pin pointed the problem in this instance, ie the USPCB between the ISO REGEN and the DAC.

 

Actually, I think you will find the issue was not the USPCB between the ISO REGEN and DAC; Rather I bet that the ISO REGEN did not take kindly to having the QED Reference USB cable between the microRendu and the ISO REGEN.  Try putting the QED cable before the ISO REGEN again to see if the problem returns.  Then you may have an answer.  

[Excommunication]

6 minutes ago, Superdad said:

Actually, I think you will find the issue was not the USPCB between the ISO REGEN and DAC; Rather I bet that the ISO REGEN did not take kindly to having the QED Reference USB cable between the microRendu and the ISO REGEN.

You´d bet! I had to break off a listening session, and suddenly the QED Reference USB cable was a no-go between the mR and ISO REGEN, where as the Nordost Blue Heaven and USPCB was OK.

 

So the conclusion is: Not all USB cables work correctly between the microRendu and ISO REGEN.

[sdube]

28 minutes ago, Excommunication said:

You just gave me an idea to switch out the USPCB entirely and add my Nordost Blue Heaven. I did that 3 minutes ago and likewise the music plays, and mR was found effortlessly. We might have pin pointed the problem in this instance, ie the USPCB between the ISO REGEN and the DAC.

So we might have: this particular connection with the USPCB in certain systems. Did you notice a change in the SQ working with the two cables, or is too early yet? I am inclined to retain USPCB between Mac Mini and Iso Regen and try a cable between the Iso Regen and the Berkeley Alpha USB. But shall wait: at the moment, the dropouts are few and far between; the SQ is great; and I don't want to risk undoing the grounding procedure (Alex's suggestion) since my mechanical/electrical/commonsense capacities are all too limited, if not shot!

[sdube]

12 minutes ago, Superdad said:

 

Actually, I think you will find the issue was not the USPCB between the ISO REGEN and DAC; Rather I bet that the ISO REGEN did not take kindly to having the QED Reference USB cable between the microRendu and the ISO REGEN.  Try putting the QED cable before the ISO REGEN again to see if the problem returns.  Then you may have an answer.  

I spoke too soon: shouldn't go meddling in uncertain terrains. (I am no Peter Wabbit.)

[Excommunication]

8 minutes ago, sdube said:

Did you notice a change in the SQ working with the two cables

If I could only take out the cotton from my ears. I hear substantial differences, that is why I need to go to great lengths of adjusting the parameters. Besides, I´m not in a AB testing scenario, which I require me if to pick up subtleties. Now can I continue to finish DSOTM before going to bed.... 

[sdube]

8 minutes ago, Excommunication said:

Now can I continue to finish DSOTM before going to bed.... 

The (Pink) Floyd are all yours, sir. (I am quite convinced by the USPCB, just fear frequent dropouts again, as Alex knows.)

 

[sdube]

Pleased to report further that my (admittedly infrequent) dropouts with two USPCBs in use, before and after the Iso Regen, might well have been due the fragile grounding ahead of the second USPCB, before the Berkeley Alpha USB, being insufficiently secure. I do want to banish thoughts of rearranging the set-up, using a cable, lush or otherwise. 

[asdf1000]

On 9/5/2017 at 5:35 PM, Superdad said:

h) The above is likely to partially defeat the digital isolators that may be inside your DAC/DDC--between the USB stage and I2S lines to the rest of its circuitry.  But they will still be somewhat effective (on the data lines) and then you should be able to utilize the ISO REGEN with its switch in the down, fully isolated position.

Hi Alex

I'm a little slow (at the best of times) but I'm trying to understand how this method (grounding the ISO REGEN's output) defeats the ground isolation of a DAC's USB digital isolator. For DAC's that have USB galvanic isolation of course.

It's probably something obvious that I'm missing.

But if the DAC's USB input is grounded, why isn't the DAC digital isolator's 'clean' output isolated from it's 'dirty' input anymore? The DAC's USB input ground connection is still isolated I thought?

If not - does this mean that ANY grounded USB audio source is defeating the galvanic isolation of a USB DAC (that has galvanic isolation)?

Appreciated

[asdf1000]

23 hours ago, Em2016 said:

 

Hi Alex

 

I'm a little slow (at the best of times) but I'm trying to understand how this method (grounding the ISO REGEN's output) defeats the ground isolation of a DAC's USB digital isolator. For DAC's that have USB galvanic isolation of course.

 

It's probably something obvious that I'm missing.

 

But if the DAC's USB input is grounded, why isn't the DAC digital isolator's 'clean' output isolated from it's 'dirty' input anymore? The DAC's USB input ground connection is still isolated I thought?

 

If not - does this mean that ANY grounded USB audio source is defeating the galvanic isolation of a USB DAC (that has galvanic isolation)?

 

Appreciated

 

 

Hi @JohnSwenson

 

If you get a spare chance, are you able to help with my understanding (or misunderstanding) of the above?

 

Appreciated

 

[JohnSwenson]

12 hours ago, Em2016 said:

 

Hi @JohnSwenson

 

If you get a spare chance, are you able to help with my understanding (or misunderstanding) of the above?

 

Appreciated

 

OK, I'll attempt this.

 

The quick response is that it depends (as is the usual response to any such question).

 

What we are trying to do is keep leakage current from the computer's power supply (or whatever is the USB source) from getting into the DAC, particularly the part of the DAC with the clock. This is the most sensitive part to the leakage current.

 

Let's assume we have a DAC with good isolation between the USB receiver and rest of the DAC, which is where the good clock resides.

 

Before we go on it is important to specify exactly what "ground" means. In audio systems there are two common uses for the term:

1: AC safety ground in a wall outlet, the "third pin". This can also be called the "earth" connection because it is usually connected to a ground rod into the earth.

 

2: The shield or ground wire in cables running between boxes, or the metal chassis in these boxes. This may or may not be connected to #1.

 

Leakage current comes from power supplies, specifically the negative output, since this is usually connected to ground #2, the leakage usually travels over cable shields, ground wires etc. That is not the ONLY way it can travel, but that is the way it travels most of the time. This leakage traveling over the shield and ground in the USB cable is what both the ISO REGEN and isolation in the DAC are designed to block.

 

So lets look at what happens when you "ground" the output of the ISO REGEN. First you need to specify which ground you are connecting a #1 or #2. If a #2, which #2? If it is the ground wire of the USB cable upstream of the ISO REGEN this is the same as flipping the switch on the ISO REGEN, in which case you are bypassing the isolation in the ISO REGEN. If it is a #2 further upstream (directly to the case of the computer etc) it is the same thing. If you connect to the #2 of the DAC or preamp etc you are bypassing the isolation in the DAC. In either case you still have the isolation of the other device, will this change the sound? Who knows, this is REALLY a crap shoot based on the your system.

 

If you are connecting to a #1 ground it is different. This one gets complicated. Let's do the simple analysis, if absolutely nothing in your system is connected to #1 ground, then connecting exactly one point to a #1 ground cannot cause a bypass of isolation. The bypass of isolation can only happen if something downstream of the isolation point is connected to #1 ground. Thus if the DAC, preamp, power amp etc has its #2 ground connected to #1 ground, then connecting #1 ground to the output of the ISO REGEN CAN cause leakage current from the computer to get into the DAC or other component. Your exact system configuration and components are going to determine how this works. It may cause a problem, it may not.

 

That was the SIMPLE analysis, now for a hint of the complex. Remember from recent posts I've been discussing high impedance and low impedance leakage current. A #1 connection can shunt high impedance leakage to the #1 ground, irrespective of what is going on with the connections above. Thus even if the #1 connection to the output of the ISO REGEN, from the simple analysis, causes bypassing the DAC isolation, the shunting of high impedance leakage may make things sound better.

 

The only way to have any hope of figuring out what may happen in a particular system is to make a full diagram of ALL components in a system, their power connections and interconnects between components, and then trace where leakage currents can originate (power supplies) and where they can go in the system (other power supplies and #1 connections).

 

As an example of how strange this can sometimes be, when working with a prototype of the ISO REGEN, I was noticing some bizarre results (leakage was not going where I thought it should go), I finally tracked it down to the headphone amp I was using, it's power supply was connected to #1 ground, thus completely changing where leakage current went. Powering this off batteries put things back to what I expected to happen.

 

I hope all this has pointed out that there are no hard and fast rules about this, leakage current can go in very unexpected ways. The laws of physics are not violated, this is not voodoo, but when you have multiple components connected together there are lots of different paths leakage can flow through, it will take the path of least impedance, whatever that might be. It might be an interconnect (analog or digital), it might be a DC cable, it might be an AC power cable.

 

Tools like the ISO REGEN and isolation in a DAC force leakage currents to take different paths, in many cases that can make things better, but not always.

 

John S.

[asdf1000]

45 minutes ago, JohnSwenson said:

First you need to specify which ground you are connecting a #1 or #2. If a #2, which #2? If it is the ground wire of the USB cable upstream of the ISO REGEN this is the same as flipping the switch on the ISO REGEN, in which case you are bypassing the isolation in the ISO REGEN.

 

Another epic reply John. You answered other questions that I hadn't even asked yet, so I'll scratch all that off the list now :-)

 

Regarding the part I've quoted - this is similar to the question I asked about bypassing a DAC's internal isolation. And I still don't get how the isolation is bypassed (I'm slow) when grounding the input (say BOTH #1 and #2 grounding).

 

In this case of grounding the ground wire of the USB cable feeding (upstream) the ISO REGEN, how does this actually bypass the isolation in the ISO REGEN? In my silly simplistic mind the ISO REGEN isolates the shield and ground, so what difference does UPSTREAM grounding (say both #1 and #2)  of the USB cable make? Obviously I'm missing something very basic.

 

And related to that - if your USB audio SOURCE that's feeding the ISO REGEN is grounded (say both #1 and #2 grounding) - does that mean you're also bypassing the isolation of the ISO REGEN since the USB cable feeding the ISO REGEN is grounded?

 

Isn't the USB cable ground connection broken by the "moat" of the ISO REGEN, regardless of upstream grounding? I feel so silly because I know the answer is no from what you've said and Alex has said but I can't see how (the mechanism) 

 

Much appreciated again

 

[asdf1000]

1 hour ago, JohnSwenson said:

Let's do the simple analysis, if absolutely nothing in your system is connected to #1 ground, then connecting exactly one point to a #1 ground cannot cause a bypass of isolation. The bypass of isolation can only happen if something downstream of the isolation point is connected to #1 ground.

 

Ok I re-read your post a 3rd time and I think this is the part that answers my questions.

 

So let's say this is the simple chain.

 

Computer USB audio source (BOTH #1 and #2 grounding) ->

USPCB ->

ISO REGEN + LPS-1 with grounded Meanwell ->

USPCB ->

Mains powered USB DAC (both #1 and #2 grounding) that has no USB isolation internally ->

RCA cables ->

Mains powered amplifier (both #1 and #2 grounding) ->

passive speakers

 

So in this case both the USB DAC and the computer USB audio source are connected to the same #1 ground, so the ISO REGEN's ground isolation will do nothing? I know the ISO REGEN does a lot of great things other than isolation (signal integrity etc), but just sticking to isolation.

 

So even though the ISO REGEN will still block leakage via ground line , I guess the leakage COULD take a different path and get into the DAC via it's #1 ground path and then out of the DAC via RCA interconnects. The exact thing we're trying to prevent/minimise.

 

I think I finally get it !

[Superdad]

3 minutes ago, Em2016 said:

So in this case both the USB DAC and the computer USB audio source are connected to the same #1 ground, so the ISO REGEN's ground isolation will do nothing? I know the ISO REGEN does a lot of great things other than isolation (signal integrity etc), but just sticking to isolation.

 

Easiest way to know if the ISO REGEN's galvanic isolation is still in effect is to simply take any multimeter/continuity checker and touch the probes to the USB shells of both the input and the output jacks of the ISO REGEN.  If you don't get a beep then the GI has not been defeated. 

[asdf1000]

8 minutes ago, Superdad said:

 

Easiest way to know if the ISO REGEN's galvanic isolation is still in effect is to simply take any multimeter/continuity checker and touch the probes to the USB shells of both the input and the output jacks of the ISO REGEN.  If you don't get a beep then the GI has not been defeated. 

 

Noted, thanks Alex!

 

But where it gets interesting (in my mind) is if you have a USB Audio source that has both #1 and #2 grounding and your USB DAC has the same (both #1 and #2 grounding)...

 

Even if this USB DAC has built in USB isolation, you are potentially screwed if you have an amp connected by RCA? And adding an USB isolator will do nothing to block leakage into the DAC - the leakage will find the back door into the DAC (#1 grounding) and then out of the DAC to the connected amp.

When I say screwed I mean in terms of this quest to block leakage into (and out of) the DAC and nothing more than that. It doesn't mean you can't enjoy music obviously, so not to throw things out of proportion. And there's obviously more to great sound quality than only leakage. But I still want to understand these mechanisms out of general interest (at a high level - I appreciate it can quickly get complicated).

 

 

 

[asdf1000]

But then things are complicated more in my mind because John's said leakage doesn't have to travel through the #1 ground. It may go through AC neutral (for example)?

 

We need everything to have LPS-1 styled PSU's built in !

 

I know Vinnie does this but more would be great. It's obviously complicated stuff to design and build (and expensive).

 

Anyway I've gone off topic and now have a leakage headache - I'll go listen to some music I think.

[nkbg]

I've been using a optical FMC setup to go between a MacBook and Devialet's ethernet input and it's sounds great, step up from USB via ISO-Regen.

 

•    MacBook->USB Ethernet Adapter--->FMC (LPS)<--->FMC(JS-2 LPS)->Ethernet->Devialet

 

and tried the following setup and it sound pretty much identical, if not more detailed

 

•    MacBook->USB Cable->ISO-Regen (JS-2 LPS)->USB Ethernet Adapter->Devialet

 

Wondering if anyone has tried powering a USB->Ethernet adapter with  the ISO-Regen?

 

PS. I'm using this adapter - https://www.amazon.com/Linksys-Ethernet-Chromebook-Ultrabook-USB3GIG/dp/B00LIW8TBG/ref=sr_1_1?ie=UTF8&qid=1522216277&sr=8-1&keywords=linksys+usb+ethernet&dpID=41rj6tmPPXL&preST=_SY300_QL70_&dpSrc=srch

[JohnSwenson]

17 hours ago, Em2016 said:

 

Noted, thanks Alex!

 

But where it gets interesting (in my mind) is if you have a USB Audio source that has both #1 and #2 grounding and your USB DAC has the same (both #1 and #2 grounding)...

 

Even if this USB DAC has built in USB isolation, you are potentially screwed if you have an amp connected by RCA? And adding an USB isolator will do nothing to block leakage into the DAC - the leakage will find the back door into the DAC (#1 grounding) and then out of the DAC to the connected amp.

When I say screwed I mean in terms of this quest to block leakage into (and out of) the DAC and nothing more than that. It doesn't mean you can't enjoy music obviously, so not to throw things out of proportion. And there's obviously more to great sound quality than only leakage. But I still want to understand these mechanisms out of general interest (at a high level - I appreciate it can quickly get complicated).

 

 

 

I don't have time to go into detail on any of this right now (I have to finish a board layout for my clock testing system). You can do a lot your self by drawing pictures and tracing out where leakage current can go. It needs power and interconnects in the drawing. On the power side include what is in the wall. Make sure you include the three wires of the AC line (hot, neutral and safety ground) so you make sure you see those connections between outlets in the room.

 

In order to do the analysis the one important thing is to understand where leakage current comes and goes:

 

Leakage current comes from a power supply (any AC connected power supply), it is created from the hot and neutral and goes through the negative pin of the supply. It has nothing inherently to do with the safety ground (third pin). Leakage current always travels in a loop (I call this a leakage loop), from the AC line, through a supply, somehow to another supply, back to the AC line, then through the AC line to the original supply.

 

Safety ground CAN be part of this, if there is a connection between the safety ground and the negative of a supply. This is the case when #1 and #2 grounds are connected somewhere.

 

So to find out what is happening, draw the diagram and start tracing leakage loops from one supply to another, make sure you trace through the three wires in the wall from one plug to another. When you do this the questions you have just asked should be obvious. Just remember the hot/neutral in the wall (or power strip) are always part of the loop and the safety ground MAY be part of the loop.

 

John S.

[ambre]

Dear John,

 

What happens if you don't use the AC safety ground in a wall outlet. The   "third pin" so called the "earth" connection.

Does dis help avoiding / help avoiding leakage?

 

This very often the case in Europe especially the Netherlands.

Not all houses or rooms especially  on the upper floors do have an earth connection. .

 

Ps. The polarity of the + / - poles has been checked/ changed  by minimizing its residual ground currents.

 

Very best regards,

 

[Superdad]

4 minutes ago, ambre said:

What happens if you don't use the AC safety ground in a wall outlet. The   "third pin" so called the "earth" connection.

Does dis help avoiding / help avoiding leakage?

 

Leakage is still there!   To quote what John said:

"Leakage current comes from a power supply (any AC connected power supply), it is created from the hot and neutral and goes through the negative pin of the supply. It has nothing inherently to do with the safety ground (third pin)."

[ambre]

THAT'S FAST  THANKS FOR REPLY