Uptone Regen and your DAC. What DAC do you use?

[Solstice380]

Mac mini w/JS-2 and MMK fan controller running HQPlayer > Mapleshade Plus or YFS Reference data only cable > Regen powered from JS-2 > McIntosh D150 (as DAC going thru my pre) (everything powered from a PS Audio AC Regenerator)

 

Definitely a step in the right direction! The much-referred-to "layer of grunge" has been beaten into a corner. Can't wait for the Amber to vanquish it from my system! Lower resolution systems may or may not hear the biggest improvement. We still live in a "weakest link" world and only the Lone Ranger had a silver bullet!

[fmak]

is how poor the usb interface from a PC is. This has been pointed out right from the beginning and ignored

for many years, perhaps due to the convenience of usb.

 

Some form of in Computer adapter with Regen/Wyrd/iFi USB Power/Sotm Card or even the cheaper

Chinese ElFidelity usb filter characteristics, powered from a high quality PS, is really called for. This

adapter should work well across a number of motherboards and should not cost hundreds of euros.

[Hiro]

is how poor the usb interface from a PC is. This has been pointed out right from the beginning and ignored

for many years, perhaps due to the convenience of usb.

 

Some form of in Computer adapter with Regen/Wyrd/iFi USB Power/Sotm Card or even the cheaper

Chinese ElFidelity usb filter characteristics, powered from a high quality PS, is really called for. This

adapter should work well across a number of motherboards and should not cost hundreds of euros.

 

The question is, what is the problem here? Is it the USB interface or a particular PC, or a combination of the two?

 

BTW, is Mac Mini still considered the best stationary computer for use in computer audio?

[Daudio]

is Mac Mini still considered the best stationary computer for use in computer audio?

 

No, it never was. It is considered a very, very good combination of price, features, footprint, ease of use, SQ, build quality, etc. But not necessarily the best of any of those qualities.

[PeterSt]

But guys, most of those DAC manufacturers claim their USB inputs are isolated/immune/reclocked/etc. and that all this stuff in front of them can't make any difference!

 

(Great thread though. Thanks for starting it Al.)

 

Hey Alex, then you saw more of those DACs than I did.

Undoubtedly you saw a NOS1 in there but FYI that is the normal version - not the isolated one.

Not that the isolated (NOS1a) will not show a difference with your Regen; I am pretty sure it will - I even think more so.

yup

 

Peter

[fmak]

The question is, what is the problem here? Is it the USB interface or a particular PC, or a combination of the two?

 

BTW, is Mac Mini still considered the best stationary computer for use in computer audio?

 

usb from computers have very poor power supplies and noisy eye patterns. usb to I2S 'Isolation' chips also increase

rather than eliminate jitter.

 

USB cables also play a significant part in influencing audio performance as part of the 'system'.

 

When I buy usb cables, I sometimes buy 5 to 7m and cut these up to make various length of cables,

carefully terminating them with all copper plugs (which are still relatively poor where the contacts and

substrates are concerned). The way the shields are terminated in, for example, Wireworld Starlight Silver

cables causes changes in SQ as is evidenced here with Ground Lift resistors. The whole thing is a can of

worms and some of the well reviewed cheaper cables actually sound awful to me (eg Chord Silver).

 

I personally would stay well away from computers such as Mac Minis with their fans and difficulty in

modding in favour of low power PCs running Server 2012/ Win 8.1 x64) with minimal non audio duties.

[Jud]

Hey Alex, then you saw more of those DACs than I did.

Undoubtedly you saw a NOS1 in there but FYI that is the normal version - not the isolated one.

Not that the isolated (NOS1a) will not show a difference with your Regen; I am pretty sure it will - I even think more so.

yup

 

Peter

 

As I said to Alain in a PM:

 

We've been saying if a USB cable makes a difference in your system, it is likely the Regen will. (For some of the same reasons, I'm supposing.)

 

When I listened to the NOS1a for a couple of weeks, I found USB cables did make a difference (though not as much as with my own DAC). So the Regen could well make a difference in the sound of the NOS1a.

[firedog]

The USB reception in the DACs also has to take some of the blame. It's not all the PC.

 

 

is how poor the usb interface from a PC is. This has been pointed out right from the beginning and ignored

for many years, perhaps due to the convenience of usb.

 

Some form of in Computer adapter with Regen/Wyrd/iFi USB Power/Sotm Card or even the cheaper

Chinese ElFidelity usb filter characteristics, powered from a high quality PS, is really called for. This

adapter should work well across a number of motherboards and should not cost hundreds of euros.

[fmak]

The USB reception in the DACs also has to take some of the blame. It's not all the PC.

 

It's a system, but the elements have to be dealt with along the chain. The view that it is the dac mostly is negated

by the improvement the Regen and similar devices brings.

[firedog]

It's a system, but the elements have to be dealt with along the chain. The view that it is the dac mostly is negated

by the improvement the Regen and similar devices brings.

 

Or it means that if DAC designers did a "really good" job of designing their USB input, the Regen wouldn't make so much of a difference. I'd bet very few DAC designers are even aware of the issues that John and Alex thought about when designing the Regen.

[Hiro]

usb from computers have very poor power supplies and noisy eye patterns. usb to I2S 'Isolation' chips also increase

rather than eliminate jitter.

 

Not good.

 

 

I personally would stay well away from computers such as Mac Minis with their fans and difficulty in

modding in favour of low power PCs running Server 2012/ Win 8.1 x64) with minimal non audio duties.

 

Any specific recommendations?

 

I presume you're not talking about a typical PC such as the one here

 

[Hiro]

It's a system, but the elements have to be dealt with along the chain.

 

And since it all starts with the PC, I would prefer to start from optimizing the computer/source, than messing with the filters later on. Unless eliminating all distortion from the computer is not possible, in which case some additional signal filtering might be necessary.

[Jud]

I'm not sure how useful it is to assign some sort of proportional "fault" between PC and DAC. Better to do as John and Alex have: understand and optimize (at least to an extent) their interaction.

[Jud]

And since it all starts with the PC, I would prefer to start from optimizing the computer/source, than messing with the filters later on. Unless eliminating all distortion from the computer is not possible, in which case some additional signal filtering might be necessary.

 

I think viewing what is a two-way interaction as one-way from PC to DAC loses something.

[Hiro]

I think viewing what is a two-way interaction as one-way from PC to DAC loses something.

 

Jud, I don't think I understand your point - are you saying that DAC affects the performance of the PC?

[Hiro]

The USB reception in the DACs also has to take some of the blame. It's not all the PC.

 

Of course, but if the signal from the computer could be made clean to begin with, we wouldn't have to rely on extensive signal filtering along the way...

[Superdad]

Or it means that if DAC designers did a "really good" job of designing their USB input, the Regen wouldn't make so much of a difference. I'd bet very few DAC designers are even aware of the issues that John and Alex thought about when designing the Regen.

 

Well, if staying with USB as a transport/input format/protocol (for both market ubiquity reasons and computer OS and app support reasons) one needs to take a step back and examine the tools, chips and techniques available to DAC designers.

 

With varying degrees of skill and success, most competent engineers will make an effort at separating the ground planes of the "dirty" input side of their DAC and the "clean" side. They all choose from a limited range of digital isolators which themselves work on various principles (tiny RF transmitters/receivers, optical couplers, tiny transformers, magneto-resistors, etc.) and decide how many data channels to pay for (some of these chips get pricey). ALL of these isolators themselves add jitter (some of them a lot), so hopefully everyone will reclock with a flip-flop after the isolators.

 

Now where do these galvanic isolators go? Always AFTER the USB processor (be that a pre-designed one like an XMOS, or the DAC firm's own USB core code in an FPGA), which itself is, in most all instances fronted by a USB PHY chip. Those PHYs are nasty, complicated little buggers, in charge of extracting the data bits from the noise of the analog voltage coming in, and they are filled with PLLs, overlapping phase clocking, and all sorts of crap that have nothing to do with audio USB. (There is no such thing as an "audiophile PHY")

 

Anyway, back to the isolation attempts: Sure, galvanic isolation to separate the ground planes helps keep directly generated ground plane noise modulation out of the "clean" side, and if done well with truly separate power supplies might actually keep that stuff from affecting the master clock (assuming the added jitter of the USB processor, isolators, and flip-flops is not too bad).

But what of the data itself? The signal--and whatever effects the USB processor, PHY, USB cable, etc. had on it--goes right on through those isolators. It has to or we would not have data to feed the DAC side. I'm not an engineer and I'm not explaining it entirely accurately, but John has been looking at what happens at the master clock and how stuff way upstream gets through and affects it. That's how and why the REGEN was born.

 

 

As to the suggestion of building a REGEN circuit into a DAC to feed its USB input:

Well, first remember that the REGEN is not magic, it is just a chosen USB hub chip fed by a good clock, a really great regulator, and a careful power network (John's "hierarchy of charge" philosophy)--and done with a 4-layer board with a lot of attention paid to impedance matching. (We are trying to get set up to do an eye-pattern on its output; anyone have a 3GHz scope they can loan us?) It works because it gives the PHY and USB processor a better signal so that those chips don't have to work as hard, which in turn generates less bursty current spikes, noise and "packet-noise" (sometimes referred to as "logic induced modulation").

 

So yes, one could stick a REGEN board inside a DAC. Of course you would still need/want to feed it with a completely separate power supply--otherwise you defeat a lot of the benefits.

 

 

But for the future? We would love to move beyond USB altogether and leave behind 80% of the above issues. Certainly I2S goes a little way towards that, but it is fragile and really not meant for external use (though LVDS helps). But to really do I2S right, one needs to feed the master clock back to the source side, and almost nobody is doing that.

John and I have discussed some more radical solutions, but in the real world acceptance of new standards is VERY difficult to accomplish--and one always comes back to software support as well.

 

Ethernet, if one can avoid both DLNA and full OS/processor requirements at the DAC end could be a good thing as well. John and I have been working on a USB>Ethernet Audio Bridge solution for OEMs for some time, but some USB is still involved in that, and I admit to recently becoming curious about the non-DLNA AES67/Ravenna, and what hardware is required inside the DAC.

 

I've rambled on long enough and need to get back to work.

 

Ciao,

 

--Alex C.

 

P.S. Of course someone could design a highly optimized, low power computer with really great USB output. And I don't mean with commercially available boards...

[Superdad]

Of course, but if the signal from the computer could be made clean to begin with, we wouldn't have to rely on extensive signal filtering along the way...

 

The REGEN is NOT a filter though. It is simply putting the creation of a good USB signal right at the input of the DAC. Perhaps the only reason it does not ameliorate all the effects of a USB cable (or the computer) is that it does not galvanically isolate from the computer.

While I have previously discussed what THAT would take here, given the quality we are getting from the new "amber" REGEN, we are just not inclined to go there this year.

[Jud]

Jud, I don't think I understand your point - are you saying that DAC affects the performance of the PC?

 

Yes, which in turn further affects the signal sent to the DAC.... Have a look back at some of John Swenson's old posts and you'll find more detail.

 

I've seen people post here that any DAC that doesn't handle whatever the computer sends is defective; or that the computer should be completely optimized so we don't have to worry about the DAC. IMO both of these are too reductionist. Both the PC, the DAC, and the interaction between them should be accounted for.

[Hiro]

I've seen people post here that any DAC that doesn't handle whatever the computer sends is defective; or that the computer should be completely optimized so we don't have to worry about the DAC. IMO both of these are too reductionist. Both the PC, the DAC, and the interaction between them should be accounted for.

 

I'm simply for prevention rather than treatment

[Hiro]

The REGEN is NOT a filter though. It is simply putting the creation of a good USB signal right at the input of the DAC. Perhaps the only reason it does not ameliorate all the effects of a USB cable (or the computer) is that it does not galvanically isolate from the computer.

 

If this solution (REGEN + galvanic isolation) could completely ameliorate all the effects of a computer in the signal chain (in effect making every computer to sound the same - or as the best computer transport there is), it would be really something.

[sandyk]

usb from computers have very poor power supplies and noisy eye patterns. usb to I2S 'Isolation' chips also increase

rather than eliminate jitter.

 

USB cables also play a significant part in influencing audio performance as part of the 'system'.

 

When I buy usb cables, I sometimes buy 5 to 7m and cut these up to make various length of cables,

carefully terminating them with all copper plugs (which are still relatively poor where the contacts and

substrates are concerned). The way the shields are terminated in, for example, Wireworld Starlight Silver

cables causes changes in SQ as is evidenced here with Ground Lift resistors. The whole thing is a can of

worms and some of the well reviewed cheaper cables actually sound awful to me (eg Chord Silver).

 

I personally would stay well away from computers such as Mac Minis with their fans and difficulty in

modding in favour of low power PCs running Server 2012/ Win 8.1 x64) with minimal non audio duties.

 

fmak

You are a brave man ! (grin)

The whole USB audio thing is indeed a can of worms and expensive to get right. The original USB audio implementation before Gordon Rankin (mainly) was very mediocre indeed.

Regards

Alex

[sandyk]

I'm not sure how useful it is to assign some sort of proportional "fault" between PC and DAC. Better to do as John and Alex have: understand and optimize (at least to an extent) their interaction.

 

And that started with the realisation that a standard Mac Mini had vastly improved SQ capabilities when powered via a decent linear PSU, and fan electrical noise was reduced markedly by overcoming problems due to PWM fan control.

[Jud]

I'm simply for prevention rather than treatment

 

I know, Hiro, and I would be too if such a distinction existed in reality. But actually *both* computer and DAC optimization are *both* prevention and treatment together.

[wdw]

And that started with the realisation that a standard Mac Mini had vastly improved SQ capabilities when powered via a decent linear PSU, and fan electrical noise was reduced markedly by overcoming problems due to PWM fan control.

 

All this is very true but the rub is in controlling this now quieted computer. Seems to me that the software options for driving your music through the new PC/MAC are still lacking. To read of the level of work a poster may undertake to set up a song or playlist with most of the popular options suggest that it is on this front the real work needs to be done unless we all move to dedicated servers with minimal software.

There will always be the hard core that really enjoy the tweaking and futzing about but, in truth, this isn't as much about the music as just farting about as we (silly) men are prone to do...nay?