I2S: Is it a good external interconnect? Give your opinion and findings!

[timequest]

Thanks Gordon (note I didn’t call you Mr. Rankin – we’re becoming friends….!!!) Anyone reading this thread will realize that I am simply going through what most audiophiles experience when they lay out cash for a product that they believe to be the next great thing – then they read anything that may even remotely contradict that belief. Anyway, as was pointed out by my other new friend Clay, I will only be using the PWD (DAC).

 

PS has said of their PWD (in a forum – not in any official release information – not that it matters, I just don’t want to put words in anyone’s mouth) that, “…we popped for the license fee on USB so we now have the way cool 96kHz/24 bit capability going directly to I2S in the PWD.” I assume this is an “agreed upon good thing?”

 

Here’s the really great thing about the current state of digital…It’s getting really good and there are some really good options available to build a true high-end music server; and that is something that we can all agree on....well, I don’t know, there’s always Michael Fremer (I mean Mr. Fremer – we’re not friends yet)

 

PS – “TimeBandit” was already taken, thus I opted for TimeQuest – which is actually more relevant, for even though I have stolen time here, I am always – in every aspect of my life, trying to find more time (aren’t we all).

 

Cheers friends (I really do mean it)

 

 

[Audio_ELF]

TimeQuest said... "I am simply going through what most audiophiles experience when they lay out cash for a product that they believe to be the next great thing – then they read anything that may even remotely contradict that belief"

I quite understand your feeling TimeQuest ... I've promised myself once I finally buy my new system I'm going to be staying out of the forums - of course I also know that wont happen :-)

 

Eloise

 

[timequest]

Frustration and the outlay of ridiculous sums of money are only the primary symptoms of audiophilia. Then there is the obsessive compulsive behavior, such as day-dreaming about audio components and the deep desire to be near such components – or “connected” to the pulse of the industry (via forums, websites, magazines, at the local dealership – they see you coming). It can get to the point that we find ourselves online when we could be at the dedicated listening position. Just try staying away from the forums. I want to (really).

 

[The Computer Audiophile]

"It can get to the point that we find ourselves online when we could be at the dedicated listening position."

 

I've combined both. I frequently write articles online from my listening position :~)

 

[CG]

Being the perpetually confused guy that I am, I have a question.

 

Imagine that you just got married or otherwise attached to someone you really like.

 

A magazine/web/TV review comes out that says "Mates with blond hair, blue eyes, and heights within 1.77 cm of your own height are the best match. This is according to our measurements and our reviewers."

 

Now, do you:

 

a) dump the mate

 

b) scan the internet for validation of your selection

 

c) start arguments on various web forums to defend your selection and tell everyone else how stupid they are

 

d) go on and be happy with the choice you made - you have to live with that person, after all, not anybody else

 

e) none of the above

 

 

 

[johnnyturbo]

ah, here is one alternative understanding of your post and related posts.

why the apparent continual fascination with the "new": this a disease: The Fetish of Commodities; whereby lifeless inanimate objects take on lifelike magical qualities.

 

another pov: all the sound and fury is the cosmos telling us that we have too much money.....and time.

 

i agree with chris: take a break, enjoy, get a kick out of the pleasure of music.

 

[icebreaker]

"Frustration and the outlay of ridiculous sums of money are only the primary symptoms of audiophilia. Then there is the obsessive compulsive behavior, such as day-dreaming about audio components and the deep desire to be near such components..."

You are quite right and thus the reason we all are obsessing with you about your decision.

 

Following CG's thought...

Is your new mate too boxy?

Is she well connected?

Does her digital lens really matter?

Is she too jittery?

Should I compare her again with Ms. Weiss or Ms. Bryston?

Is it too late to reconsider?

Is she truly a smooth performer despite all her flaws?

 

Sometimes obsessing can be good, especially when its about important matters. (Then is it obsessing?)

Hope it all works out. :>)

 

 

[timequest]

Ahh…but if it was only so easy. Behavior controlled is not obsessive behavior – herein lies the catch.

 

CG – my first spouse was (and still is) a very attractive woman – that being among her other many attributes. My girlfriends, fiancée’s and live-ins who followed were all, in their own way, very special with different (and sometimes “better”) attributes than the preceding women. My wife (and wonderful mother of my children) is quite simply the most wonderful person companion and friend that I could ever hope to spend my life with. The fact that she is younger and more beautiful than any preceding her may follow your logic. That said however, I can’t help but question your illogical analogy. There are always choices CG – in all aspects of life. But again, I was talking about audio equipment.

 

 

[Wavelength]

Timebandit,

 

If you haven't noticed I hate people that don't sign their own names. Who are you???

 

PS has said of their PWD (in a forum – not in any official release information – not that it matters, I just don’t want to put words in anyone’s mouth) that, “…we popped for the license fee on USB so we now have the way cool 96kHz/24 bit capability going directly to I2S in the PWD.” I assume this is an “agreed upon good thing?”

 

Yes PS as well as Empirical, Benchmark, BelCanto and many others paid for the Adaptive code by CEntrance. But do note that all three of these companies clean up the jitter before doing it with anything. I hope for you sake that they are not outputing direct TAS1020 jitter to the I2S stream... ouch 2800pS is a ton of jitter.

 

Thanks

Gordon

 

[timequest]

So you do hate me! I have a similar problem with professionals who use poor grammar, except I don’t hate them at all, I am merely annoyed with their lack of professionalism.

 

Your new friend,

Ben

 

 

[CG]

"There are always choices CG – in all aspects of life. But again, I was talking about audio equipment."

 

That is *exactly* my point as well. It just applies to audio as in other aspects of life that you refer to.

 

There are people who like headphones. Ones who like horns. Ones who like electrostatic panel speakers. People who prefer time-aligned speakers. People who don't. People who like single ended triode amplifiers. People who like monster solid-state amplifiers.

 

I could fill this entire page with the various combinations. Are they all wrong? Is the guy who likes raspberry shortcake right and the guy who likes strawberry shortcake better wrong?

 

My point is simple. What you like is just fine for you. Perhaps technically it is not the best, but that's not what matters to you.

 

So, if this is just a question of what is technically better, all the hard data already posted from the reviews and other test measurements says it all. If you happen to be happy with your purchase, that should be good enough.

 

What am I missing?

 

[Mr.C]

Summing up: Even though some companies can make I2S work, it is inherently at a disadvantage because it doesn't have any built in corrections for cable problems or the original problems associated with an interface. This is a problem because it places the final clock away from the DAC chip that it is meant to be clocking and doesn't have any way of rectifying the incoming jitter problems which will invariably occur. Is this the gist?

 

I'll be curious to see how the Perfect Wave products pan out over time in terms of the I2S interface.

 

[idiot_savant]

again ( damn you! )

 

 

your friendly neighbourhood idiot

 

[idiot_savant]

Although it is a fairly smart move to use HDMI cable...

 

 

your friendly neighbourhood idiot

 

[timequest]

I just checked out Wavelength’s website (is there any reference to Van Morrison’s album – Van IS the man. I suppose it has something to do with real wave forms). Anyway…damn, I wish I would have done so before pissing off GR. The gear on that sight is absolutely awesome looking stuff. From what I gather here, it sounds great as well.

 

This thread has been thoroughly stomped. I am going to search for another one to inject some controversy (it’s stimulating).

 

Cheers to all (no, REALLY, it’s after 5:00 – somewhere, I’m fisted…um…ahh). (Really).

 

 

 

[cfmsp]

 

 

"This thread has been thoroughly stomped. I am going to search for another one to inject some controversy (it’s stimulating)."

 

Ben,

 

How about this? Perhaps post on the PS Audio forum that it's unprofessional/disrespectful/etc. of Paul McGowan to post on an open, public forum that his USB implementation is 'as good as it gets', and that USB will never sound as good as other protocols, when he should know that Gordon's implementation is better than the Centrance licensed version that Paul 'finally popped for'?

 

 

Or maybe just post that a six year old ipod has less jitter than the Perfect Wave via I2S?

 

your pal in controversy,

clay

 

[timequest]

Doouugh...I said I was going to leave it alone. You're tempting me Clay.

 

I don't want Chris to univite me....

 

[cfmsp]

 

 

well, maybe you've already got some controversy started at PS Audio anyway, given your post about the likely jitter coming out of the TAS1020 chip.

 

If Paul is sincere about not having tools to measure jitter (as has been recently stated), he's not really in a position to respond. I'd guarantee that the figures that Gordon quoted were from his own tests, with his own jitter testing equipment.

 

clay

 

 

 

 

 

[timequest]

Controversy...?? I seek the truth my friend.

 

I think it's been fun. I hope no one has been offended.

 

Thanks.

 

[The Computer Audiophile]

Hi Timequest - I've thoroughly enjoyed the progression of this thread. I'm not making any judgments on the components discussed or any conclusions people may or may not have reached. I think I enjoy the camaraderie going on here more than anything :~)

 

[cfmsp]

 

 

"I seek the truth my friend."

 

The truth? Audiophiles don't want truth.

 

Those seeking 'objective' truth use ABX testing.

 

Absent that, it's all opinions, and that's how it should be, as far as I'm concerned.

 

Clay

 

 

 

[timequest]

Ahh…Clay, your perspicacious astuteness is astounding.

 

[jkeny]

I've just read this whole thread after being directed here on foot of my post about using I2S from a firewire Konnekt to an external DAC.

 

This thread started off so well with some great technical info provided by idiot_savant but then seemed to degrade into confusion with some comparing I2S Vs SPDIF Vs Firewire Vs USB. I don't see this as valid as Firewire & USb are computer transport standards & the others are not. The real comparison, in my opinion, is between SPDIF & I2S.

 

Gordon states that I2S sounds like a cheap cd player at anything longer than 2 cms signal length - I'd like to see the evidence for this. Idiot_savant says the spec for I2S mentions < 6" signal length. I can understand how high speed signals which need to be tightly coupled require a fine tolerance in the transmission spec BUT HDMI, with high MHz signals, achieves this over cables longer than a meter . Does this remove the length problem?

 

SPDIF has similar issues with signal termination & reflections PLUS it also has the issues inherent in using an analogue PLL for clock recovery. Analogue PLL used in SPDIF receivers appears to generate data correlated jitter, the worst & least tolerated kind. Using software (in FPGA) or a digitally implemented PLL ala Sabre DAC to recover the clock, seems to have advantages. Maybe this is the way forward but for my use, as a DIYer, I don't have access to this software or digital PLL without tying into a particular product.

 

[cfmsp]

 

"This thread started off so well with some great technical info provided by idiot_savant but then seemed to degrade into confusion with some comparing I2S Vs SPDIF Vs Firewire Vs USB. I don't see this as valid as Firewire & USb are computer transport standards & the others are not. The real comparison, in my opinion, is between SPDIF & I2S."

 

Perhaps you missed the point of people comparing I2S to Firewire and Async USB? The debate was not specifically about the relative merits of S/PDIF vs. I2S, it was about the claims of PS Audio and relative merits of I2S as a protocol between computer/transport and DAC. It is PRECISELY because Firewire and USB are, as you say, "computer transport standards", that they were compared to PS Audio's use of I2S as a 'computer transport standard', to wit, using I2S to communicate digital audio data between two separate devices over unspecified distances, presumably longer than those on a circuit board.

 

EDIT: seriously, I mean no offense, I'd delete this thread, but I can't, so I'll leave it intact and hope I didn't piss you off for no reason.

 

YMMV,

clay

 

[idiot_savant]

I understand your problem if attempting to DIY an interface, and the points you make are valid, except:

 

HDMI & SPDIF were both designed from the outset to connect different boxes together from the outset, whereas I2S was not. This means that there are extremely tight specs for designing a piece of kit with HDMI, looser specs for designing kit with SPDIF - both have "eye" diagram specs, impedance specs, voltage specs, amount of shielding that is expected etc. I2S does not - it's actually relatively slow ( hundreds to thousands of times slower than HDMI for instance ).

 

It was actually a smart move of PS audio to use an HDMI cable & connector - they're both over spec'ed for the job in hand.

The problem with I2S is that you're transferring essentially an analogue signal in terms of the bitclock over a long stretch of wire, with no chance of using traditional techniques of cleaning it up at the other end ( as I mentioned previously, you can't use a PLL with I2S ). It's a real shame that the I2S-E standard died a death, as this would have been a way forward.

 

I think Gordon was slightly over the top in his analysis as well...

 

Does your DAC have a wordclock in? Many bits of pro kit have a wordclock input - looks like the Konnekt doesn't have a wordclock out, but your proposed I2S frame would be the equivalent - the DAC could then use the wordclock for it's clocking stuff, and the SPDIF stream for the data...

 

your friendly neighbourhood idiot