ISO REGEN launch thread! (product web page up; photos, etc.)

[Superdad]

Hey, I just started a new thread for ISO REGEN Listening Impressions and it has some pictures you gents will want to see!

By the way, @Jud and @lmitche: The embargo is now lifted and you are free to post what you have heard with ISO REGEN so far (they were beta testers and were sent final units as I was on my way to vacation on April 29th).

 

[Jud]

Just now, Superdad said:

Hey, I just started a new thread for ISO REGEN Listening Impressions and it has some pictures you gents will want to see!

By the way, @Jud and @lmitche: The embargo is now lifted and you are free to post what you have heard with ISO REGEN so far (they were beta testers and were sent final units as I was on my way to vacation on April 29th).

 

 

Busy as all heck right now (look who I'm talking to  ), but yes, when things calm down a bit I'd be happy to.

[R1200CL]

1 hour ago, Superdad said:

However, for a DAC's audio master clocks (or the audio freq. clocks in a USB>S.PDIF converter which get embedded in the SPDIF/AES stream and supplant the DAC's clocks (though often a DAC will reclock that input), that is where no expense should be spared (though the rest of most DACs add more jitter from their circuitry and never get the full benefit of an über-expensive clock).

 

Looking forward to your and John's solution on this

 

[kalinka]

The iso regen has a recommended burn-in period or is it already optimun out of the box?

[spacexpert]

4 hours ago, kalinka said:

The iso regen has a recommended burn-in period or is it already optimun out of the box?

From the Listening Impressions thread: Please give your ISO REGENs a few hours to "warm up."  Clock oscillators always sound better when warm...

[kalinka]

1 hour ago, spacexpert said:

From the Listening Impressions thread: Please give your ISO REGENs a few hours to "warm up."  Clock oscillators always sound better when warm...

 

What brings us another question: should we turn on the regen some time prior to start listening?

 

iFi recommends about half an hour before starts listening to their ipurifier, for example.

[pl_svn]

Never turned my Regen OFF and will just do the same with the ISO Regen

I don't think power consumption is anything meaningful (even more if sitting idle)

[scan80269]

Talk about a roller coaster ride in just one morning!

 

My ISO REGEN order arrived this morning (there's definitely an advantage to living in the same state as UpTone - THANKS Alex!!), and was about to tear into the package, when I heard from my wife that she got into a car accident just a quarter mile from home!  A Lyft driver made an unsafe left turn and crashed into my wife's month-old Mercedes C300 (she was going straight with right-of-way), which then hit a pedestrian crossing sign pole.  A total of 4 airbags deployed.  She seems to have sustained only some bruises on the hands (from the airbag) and a scrape on the shoulder (from the seat belt), but I'll need to bring her to be checked out more thoroughly.

 

I guess my planned posting of ISO REGEN listening impressions will have to be postponed.

 

[austinpop]

10 minutes ago, scan80269 said:

Talk about a roller coaster ride in just one morning!

 

My ISO REGEN order arrived this morning (there's definitely an advantage to living in the same state as UpTone - THANKS Alex!!), and was about to tear into the package, when I heard from my wife that she got into a car accident just a quarter mile from home!  A Lyft driver made an unsafe left turn and crashed into my wife's month-old Mercedes C300 (she was going straight with right-of-way), which then hit a pedestrian crossing sign pole.  A total of 4 airbags deployed.  She seems to have sustained only some bruises on the hands (from the airbag) and a scrape on the shoulder (from the seat belt), but I'll need to bring her to be checked out more thoroughly.

 

I guess my planned posting of ISO REGEN listening impressions will have to be postponed.

 

 

How scary! Yes - family first. Hope she checks out OK. Best wishes...

[pam1975]

good luck and all the best to your wife!

[Superdad]

13 minutes ago, scan80269 said:

...I heard from my wife that she got into a car accident just a quarter mile from home!  A Lyft driver made an unsafe left turn and crashed into my wife's month-old Mercedes C300 (she was going straight with right-of-way), which then hit a pedestrian crossing sign pole.  A total of 4 airbags deployed.  She seems to have sustained only some bruises on the hands (from the airbag) and a scrape on the shoulder (from the seat belt), but I'll need to bring her to be checked out more thoroughly.

 

Oh no Sam, that is terrible!!  I hope your wife is okay.  Please keep us posted.  

[ted_b]

Wow, Sam...that is scary as hell!  When I saw the post in my email I freaked when it said "which then hit a pedestrian" and failed to finish reading "cross sign pole".!!!   Anyway, hope she is ok (mostly emotional).  ISO Regen feedback can wait (til tmrw ).  Mine arrives Monday.

[JohnSwenson]

On 5/19/2017 at 10:44 AM, Daudio said:

 

I see that you have gotten some very good answers to this and subsequent questions, but I thought I might pipe up and answer you in a slightly different way. I certainly don't know everything about USB, but I did spend some significant time rummaging through the USB 2.0 Spec documents, so here goes.

 

 

I think of the clocks in the host computer, any internal/external hubs, and the PHY receiver chips in the endpoint device as controlling the USB pipeline, syncing the signals that enable bits to flow, whether those bits are commands, status, data, markers, or whatever. The 'pipeline' is designed to work at various rates for low-level activity, as well as different, specified, application data flows.

 

This is true for all the different USB modes. Where 2.0 Async is different is that it adds the capability for the endpoint (DAC) to watch it's input buffer and respond to pseudo-interrupt messages from the host (which come from the 2.0 Async driver code), polling the DAC to allow it to request more data, or idle until it needs more. USB is a purely host-controlled interface and endpoints can't control the bus.

 

So the DAC is sending info (need data/don't) back to the host, based on the DAC's clock gating audio data out of its buffer, through the USB pipeline (which is managed by it's own low-level clocks). Said another way, is that the Async timing info tunnels thru the existing, separately timed data pipe.

 

USB Signal Integrity is a very important factor for the electronic pieces of the pipeline, at the physical level, but isn't really a part of the Async mode.

 

 

I hope this may help you, or some others understand screwy USB a little better. If I've gotten something wrong here, I'm responsible and expect to be corrected, and we will all learn    Apologies if this is too off-topic...

 

Not quite,

The upstream side is exactly the same in both adaptive vs asynchronous. The difference is in how many samples are put in each packet. The host software assumes that the clock feeding the PHY is exactly correct and frames happen at exactly 8KHz. It figures out how many samples it needs to put in each packet to exactly match the sample rate (44.1 96 192 etc). This is never an integer number, so packets do not all have the same number of samples. It will alternate packets of different number of samples so the average data rate is correct.

 

The low host just sends these packets out. There are no start or stop commands, the host just continuously sends these packets. This is the same for adaptive and asynchrounous.

 

What asynchronous mode does is add a mechanism for the DAC to tell the host to speed up or slow down. This only happens when the DAC wants to change things. This may not be very often. The host takes this information and slightly changes it allocation of samples per packet. As far as the host is concerned it is sending data out a little fast or slow. For example the host might think it is sending data out at 44102 samples per second.

 

OK so that is the mechanism, but what do different clocks have to do with sound quality?

 

Note first that none of this is hard and fast, nailed down, concrete, etc. As time goes on we learn more about what is going on, so attempts at explanations might change over time.

 

In adaptive mode the average data rate is controlled by the host, period. The DAC has to adjust itself to match. Traditionally this was done with a device called a "Phase Locked Loop" otherwise known as a PLL. I'm sure everybody has heard of these by now. Older, inexpensive PLLs were not very good, they generated a lot of jitter. Asynchronous mode was designed so you didn't need a PLL. It gets rid of the PLL generated jitter, but NOT all the other forms of jitter in your system. So it is a useful first step, but not a cure-all "nothing else matters" deal. It is not that asynchronous mode is worthless, or a "scam", it is just the first step. You have to get this done before you can start dealing with all the other issues.

 

As an aside PLLs have gotten a lot better in recent years. I could build an adaptive interface that outperforms almost anything on the market today of any type, but it would be pretty expensive. This is primarily due to the high speed communication industry, they all work on the adaptive model, the receiver has to synchronize to the transmitter, but this takes really GOOD PLLS, the engineers have been working on this a LOT in the last few years.

 

OK so what else is there? The clock that actually goes into the DAC chip consists of jitter from several sources. Before proceeding we need to talk about phase noise. The term jitter is usually specified as a single number, but this is way too simplistic, it is actually a spectrum, this is usually shown with a phase noise graph. I'm not going to go into the gory details here, but it is a spectrum, noise level VS frequency. You need this on order to see what is going on with multiple clocks in a system. They all have different phase noise and how they interact determines what winds up going into the DAC chip.

 

So how can clocks interact? Primarily through power and ground interactions. This all gets a little complex, I've tried to explain how this works in the series of articles I wrote for AudioStream, if you REALLY want some detail, go read these.

 

Every digital "stream" is timed by some clock, the phase noise of that clock is kind of a "fingerprint" on that stream, it is embedded in the timing of the stream. When that stream goes into some circuitry, some noise is generated in the power and ground signals of that circuitry. Even if that stream gets reclocked by an ultra low phase noise clock, there is still noise generated in the PG signals that has the fingerprint of the clock used to generate the stream in the first place! That noise can modulate the local clock so what come out of it is some combination of the original fingerprint and that of the local clock.

 

How much of the original fingerprint shows up in the local clock depends on the local clock itself, the power network on the board, the reclocking circuitry, the board layout and a host of other things.

 

The result is that if don't get all these things just right, the phase noise on the final clock might wind up being dominated by the upstream clock rather than the phase noise of the local clock.

 

This is why the clock used for generating the USB signal has anything to do with sound quality. At this point in time nobody has generated a receiver circuit that completely ignores the fingerprint from the USB stream. So every DAC is going to be sensitive to some degree or another to the clock used to generate the USB stream. Different implementations vary greatly as to how much they let through, so the relevance of low phase noise in the USB clock is going to vary, for some it is going to make a big difference and for some it will not matter as much.

 

Where a particular DAC falls in this range is almost random. Very few designers even think about this. And even if they do test equipment to actually measure this is very expensive so nobody is actually measuring it. So it is pretty much a crap shoot where a particular DAC winds up.

 

I'm actually trying to design some of my own test equipment that will allow me to actually measure this stuff and actually trace a clock "fingerprint" through a system. But that is probably a year or two away. But once that happens hopefully there can be some significant improvement in the situation.

 

BTW this is not just USB specific, ALL the digital music interfaces have these issues.

 

John S.

 

 

 

 

 

 

 

[Jud]

Sam, hope everything gets back to normal as easily as possible for you and your wife. (!)

[scan80269]

Thanks, guys, for the well wishes.  My wife was just a bit shook up but is apparently spared of any serious injury.  Thank God for airbags and seat belts.

 

[scan80269]

Just finished setting up my ISO REGEN to drive my modded SU-1 DDC and Holo Audo Spring DAC.  I use two LPS-1 units, one for the ISO REGEN and another for the SU-1.  Source is an AiO Win10 PC running HQPlayer.  Feeder supplies for the LPS-1s are modded Breeze Audio el-cheapo linear supplies.  This is not my usual setup.

 

Will start listening after a few hours of burn-in time.

 

I'm going to a symphony concert tonight (they'll play the Planets by Holst), so my ears should be well calibrated afterwards. ?

[R1200CL]

1 hour ago, JohnSwenson said:

I could build an adaptive interface that outperforms almost anything on the market today of any type, but it would be pretty expensive.

 

Not sure if we're talking about a DCC. But is it possible to define expensive if you know you would sell easily between 500 and 1000 units ?

 

Are we above 1K ?

[R1200CL]

2 hours ago, scan80269 said:

which then hit a pedestrian crossing sign pole.

 

Isn't this quite serious? 

Did the pedestrian survive ?

[scan80269]

4 minutes ago, R1200CL said:

 

Isn't this quite serious? 

Did the pedestrian survive ?

I'm afraid that sign pole did not survive.  It was almost horizontal after it got hit.

 

I just drove by the spot where the accident occurred, and there were no hints of the accident just a few hours ago, except for that missing pole...

 

[mourip]

4 hours ago, scan80269 said:

Talk about a roller coaster ride in just one morning!

 

My ISO REGEN order arrived this morning (there's definitely an advantage to living in the same state as UpTone - THANKS Alex!!), and was about to tear into the package, when I heard from my wife that she got into a car accident just a quarter mile from home!  A Lyft driver made an unsafe left turn and crashed into my wife's month-old Mercedes C300 (she was going straight with right-of-way), which then hit a pedestrian crossing sign pole.  A total of 4 airbags deployed.  She seems to have sustained only some bruises on the hands (from the airbag) and a scrape on the shoulder (from the seat belt), but I'll need to bring her to be checked out more thoroughly.

 

I guess my planned posting of ISO REGEN listening impressions will have to be postponed.

 

 

Glad to hear that she is OK. Makes audio seem insignificant!

[gsquared]

2 hours ago, scan80269 said:

Thanks, guys, for the well wishes.  My wife was just a bit shook up but is apparently spared of any serious injury.  Thank God for airbags and seat belts.

 

Glad to hear your wife wasn't seriously injured. That's scary stuff!

[audioarcher]

Since the new Iso Regen is a USB 3 hub, does it sound better on a USB 3 jack vs a USB 2 jack or does it matter?

 

I have one coming but not until the second batch ships out.

 

Sean

[scan80269]

ISO REGEN is not a USB3 hub.  The USB receptacles are USB 2.0, and the Superspeed portion if the hub chip inside is not connected.  John & Alex picked a specific USB3 hub chip to use as USB2 hub for the signal integrity advantage.

 

[Superdad]

10 minutes ago, scan80269 said:

ISO REGEN is not a USB3 hub. 

 

Gosh Sam, go take care of your traumatized wife.  Or go listen to the ISO REGEN's you received.  You are officially off-duty tonight for answering forum questions!  

[audioarcher]

"ISO REGEN is not a USB3 hub.  The USB receptacles are USB 2.0, and the Superspeed portion if the hub chip inside is not connected.  John & Alex picked a specific USB3 hub chip to use as USB2 hub for the signal integrity advantage."

 

Thanks for the info. Still would like to know if it works better through a usb 3 port or not.

 

I also have a Lightspeed Revive which is USB 3. I prefer it to the Regen, but ordered the new Iso Regen because of the  Isolation. Should be interesting to compare the two side by side.