15 USB/SPDIF converters shootout

[mayhem13]

Another thread down the mystical sewer pipe. At some point, reasonable people will draw correlation with magnetic fatigue fighting jewelry and the like.

[Superdad]

Sure: USB input, clocks, S/PDIF drivers (there are many ways to produce an S/PDIF signal), power supplies. Every one of the converters auditioned by the OP is designed differently. So why does it surprise you that there audible differences?

I'm not surprised.....but convinced there are no audible differences with a quality DAC on the other end. You gotta draw a line somewhere. I draw mine here.

 

I give you a list of logical reasons--a raft of areas where these converters are engineered differently--yet you are clearly stating that you refuse to accept that they can sound different. Not a very rational or objectivist stance.

 

 

Another thread down the mystical sewer pipe. At some point, reasonable people will draw correlation with magnetic fatigue fighting jewelry and the like.

 

And you wonder why I consider mayhem13 to be a troll--or at least a thread hijacker. He does this quite a bit here on CA. People will be discussing what they hear (maybe with some remastered hi-res recordings; maybe with some gear that they personally auditioned and compared) and he shows up to poo-poo it all and ultimately tells us we are deluding ourselves.

 

There is a much more popular forum site where he would be among like-minded flat-earth skeptics.

 

 

P.S. The above is not my normal tone. I am a friendly, open-minded guy. But I am tiring of his insults to the group.

[Blake]

I would have to add a +1 to all of superdad's comments above.

 

Mayhem asks us to be open-minded and explain our position, we do that but instead of observing the golden rule, mayhem simply ditches the thread with a not too subtle insult (believing that converters can make a sonic difference is analogous to believing in magnetic wrist bands.... i.e. we are fools).

 

In hind-sight, I should not have responded to mayhem's quips. My apologies to the OP (Elberoth) and this thread (which I consider to be one of the best posts of the year). I will no longer debate or interact with mayhem here on CA as it serves no purpose.

 

Mayhem, we members specifically asked elberoth (Adam) to post this thread. Adam then takes basically the better part of a day to get this post together to benefit our members and respond to our request, and then gets attacked by you for doing so. Meantime, Adam must surely be asking himself "why did I bother to help other members if this is the response I get".

 

Not a great way to keep a free flow of ideas circulating.

[pawel8]

I would have to add a +1 to all of superdad's comments above.

 

Mayhem asks us to be open-minded and explain our position, we do that but instead of observing the golden rule, mayhem simply ditches the thread with a not too subtle insult (believing that converters can make a sonic difference is analogous to believing in magnetic wrist bands.... i.e. we are fools).

 

In hind-sight, I should not have responded to mayhem's quips. My apologies to the OP (Elberoth) and this thread (which I consider to be one of the best posts of the year). I will no longer debate or interact with mayhem here on CA as it serves no purpose.

 

Mayhem, we members specifically asked elberoth (Adam) to post this thread. Adam then takes basically the better part of a day to get this post together to benefit our members and respond to our request, and then gets attacked by you for doing so. Meantime, Adam must surely be asking himself "why did I bother to help other members if this is the response I get".

 

Not a great way to keep a free flow of ideas circulating.

 

I think Mayhem is angry with himself and he needs to "unload" on somebody else.

 

I think we appreciate Adam work and time he has spent on this and other projects.

 

I might disagree sometimes with reviews,but it is learning experience and for sure I am not going personally attack reviewer.

 

Pawel

[wisnon]

Yes - my PDX and Playback Designs MPD3.

 

Thanks

Bill

Calyx Femto too, apparently.

[mayhem13]

I give you a list of logical reasons--a raft of areas where these converters are engineered differently--yet you are clearly stating that you refuse to accept that they can sound different. Not a very rational or objectivist stance. .

p.

 

Logic?......where?

 

The same reference DAC was used......jitter is reduced below audible levels

 

Noise?.....the noise floor of the chosen gear is below the level of an exhaled breath...so unless the reviewer held his breath or performed the test in a sensory deprivation chamber, noise is not relevant.

 

So what 'logical' conclusions remain in regards to a stream of 1's and 0's.

 

No hijacking here..just looking for a reasonable explanation of why there would be so much audible variance between these devices. I have yet to read one. I suspect you would like me to accept your engineering theory....which I paraphrase suggests different engineering guarantees different results?...unless I missed something.

 

And as for ' the group'.....I'm pretty sure my original post was directed towards the OP, yet everyone but has taken up a position on the topic....Which originally was a polite query.

 

To add, I'm not against USB/SPDiF converters....there's a real need for them as an interface....

[mayhem13]

.

 

Not a great way to keep a free flow of ideas circulating.

 

A 'free' flow of ideas moves in multiple directions.....

Maybe you meant a 'homogenous' flow of ideas. Is that what you want or need in a forum or discussion?

[bhobba]

Pure speculation on your part as to the audible level of jitter.....and it is quite measurable with the correct equipment. Digital communication and manufacturing rely heavily on reduced jitter levels to assure accuracy. If jitter levels are in the Pico range and you'd like to make a point for audibility, I have some beachfront property in Montana that's a real bargain too!

 

Its not speculation - verified by listening tests. Got the gear to measure jitter that low? If so Steve Nugent would like to hear from you.

 

Thanks

Bill

[bhobba]

So what 'logical' conclusions remain in regards to a stream of 1's and 0's.

 

Well I suggested, based on investigations by a very well credentialed digital engineer, Steve Nugent, the spectrum of the jitter had something to do with it. Yet you thought it was pure speculation. Of course you mentioned 'logical' by which you probably mean what you think as logical.

 

I suspect you are a DBT type and if you cant hear it that way it doesn't exist. If so be aware such tests show even cheap late model DVD players from K-Mart sound the same as high end DAC's. So if you genuinely believe such then rather that posting here you should be enjoying perfect sound and not worrying about what guys like us go on about.

 

Thanks

Bill

[ar-t]

That's not the case. The best converters have jitter below 10ps which requires very rare special equipment to measure. Steve Nugent for example cant directly measure it and had to 'guess' it via other means. And yes it is audible. For example the Audiophellio has a slightly lower jitter than Steve's Off-Ramp yet many like myself prefer the Off-Ramp. Evidently the real critical thing is not so much the level of jitter but its spectrum - which is even harder to measure. IMHO measurements are not the way to go here - but rather listening to it.

 

Thanks

Bill

 

REALLY!!!!!!!!!!!!!!!!!!!!?????????????

 

It is only hard if you have the wrong equipment. I'll leave it at that.

 

And 10 pSec, without spec'ing the frequency over which it is measured (you know, the "jitter spectrum") is a lot of hot air.

 

Actually, I think 10 pSec is too much, for what that is worth.

 

(I hope the reader that asked me to comment on this thread has received his answer. I am going back to my hole in the ground.)

[bhobba]

It is only hard if you have the wrong equipment. I'll leave it at that.

 

Its only hard if you have the wrong equipment when the correct equipment costs a lot and is supposedly rare?

 

That makes no sense. Are you suggesting it is not that rare?

 

Like I said if you have the equipment to do it Steve wants to hear from you.

 

Thanks

Bill

[bhobba]

Since we have people doubting the audible effects of Jitter I think the following article may be of interest:

 

Jitter in Digital Audio Data Streams Article By Steve Nugent Of Empirical Audio

'For instance, I use two oscillators that are both specified at 2psec RMS jitter. The two oscillators sound radically different to me when used in a re-clocker in a resolving audio system. This leads me to believe that the spectrum, or frequency content of the jitter is as important or maybe even more important than the amplitude. I also believe that correlated jitter or jitter with a relationship to the data pattern is also more audible than random jitter. This seems to be the consensus in a number of AES papers.'

 

Thanks

Bill

[dallasjustice]

Pat's got it. Nugent doesn't.

 

Its only hard if you have the wrong equipment when the correct equipment costs a lot and is supposedly rare?

 

That makes no sense. Are you suggesting it is not that rare?

 

Like I said if you have the equipment to do it Steve wants to hear from you.

 

Thanks

Bill

[bhobba]

Pat's got it. Nugent doesn't.

 

Undoubtedly.

 

The issue however is not if the equipment exists its its how much of it is about to carry out such measurements PROPERLY.

 

I have left a note on Steves forum and he can clarify exactly what the go is but he has posted on it previously which is how I know about it eg

 

'IMO jitter measurements that are meaningful cannot be made without special measurement techniques and expensive equipment. It is a non-trivial measurement with lots of dimensions. I have a customer that is a retired Tektronix engineer that pioneered jitter measurement equipment at Tek. I am planning to enlist him to do measurements for me. Correlating these to audibility is another thing entirely. At least if I have the measurements, I can do A/B's and determine what is audible to me and the relative levels and try to correlate this to the measurements. To do really meaningful correlation, one would have to simulate a range of jitter characteristics using test signals, including amplitude, spectrum and linearity, and then perform some ABX testing with several listeners using a high-quality system. Big undertaking.'

 

An issue may also be - what is a meaningful jitter measurement - but I will leave techies argue about that - I won't be piggy in the middle.

 

Thanks

Bill

[dallasjustice]

My experience with all these converters is similar to Elberoth. The Art Legato ii and the Berkeley Alpha USB are the best. They are very close in performance. The only difference is that the Berkeley does 176 and 192 which helps make some of my crappy redbook sound excellent along with HQplayer. The other difference is that the Berkeley costs 2.5 times more. Ive also had the Nugent converter, ART Veloce, Wavelinks 96 and 192. Yes, I know that my DAC must suck if a converter can make it sound better than asynchronous USB. :-) Every dac uses different methods to attenuate jitter. Therefore, I am not surprised there is so much disagreement.

[ar-t]

Its not speculation - verified by listening tests. Got the gear to measure jitter that low? If so Steve Nugent would like to hear from you.

 

Thanks

Bill

 

Anyone who wants our services knows where to find us. It isn't that hard. We may smell bad, but no one knows that, via e-mail.

 

(Translation: the manufacturers that want to know have contacted us. Draw your own conclusion.)

[bhobba]

My experience with all these converters is similar to Elberoth.

 

Same here. At first it surprised me but now I find the quality of USB converters in your typical DAC to be so low its not suprising at all.

 

And the reason they sound different? From my experience and what technical guys who I respect say (not just Steve Nugent - but also a guy put my way who posts as Zen Electro and makes his own Zen clock) its the spectrum of the jitter that's the reason.

 

Thanks

Bill

[ar-t]

Undoubtedly.

 

The issue however is not if the equipment exists its its how much of it is about to carry out such measurements PROPERLY.

 

............snip..............

 

An issue may also be - what is a meaningful jitter measurement - but I will leave techies argue about that - I won't be piggy in the middle.

 

Thanks

Bill

 

Hey, diddle-diddle.

Piggy in the middle.

Goo-goo-ga-choo.........

 

Let me put this in a way that may make sense, although I am not going to 'splain why.*

 

At one time, we thought if you went down to 1 Hz, that was good enough.

Then we got the right gear, and we could go down to 0.1 Hz.

 

We found out, the hard way, you need to go down to 0.01 Hz.

 

So, anyone using an overpriced Tek 'scope, that measures the telecom jitter spec, from 100 kHz to 12 MHz is whistling Dixie, put no one is putting coins in their cup.

 

* = A certain troll, who argues incessantly, with former (or present) employees, that nothing we do will work, and we are liars, until he uses it in his "products", will undoubtedly read this. I want the satisfaction of hearing the deafening silence, when he contacts every oscillator company, in the world, and asks "What is your jitter at 0.01 Hz?"

 

I know.............I'm rotten.

[bhobba]

Anyone who wants our services knows where to find us. It isn't that hard. We may smell bad, but no one knows that, via e-mail.

 

(Translation: the manufacturers that want to know have contacted us. Draw your own conclusion.)

 

Maybe he got it some other way like from the Tektronix guy.

 

But that's not the point - the point is carrying out proper jitter measurements and interpreting them is far from a trivial undertaking and certainly way beyond a guy that managed to get get a heap of converters together and do some listening tests. Guys like Mayhem in suggesting that path are being - well - silly.

 

If he want to base his decisions on measurements - go ahead - but why he feels compelled to push his view down the throat of those with a different perspective - well we all can draw our own conclusions about that.

 

Thanks

Bill

[ar-t]

My experience with all these converters is similar to Elberoth. The Art Legato ii and the Berkeley Alpha USB are the best. They are very close in performance. The only difference is that the Berkeley does 176 and 192 which helps make some of my crappy redbook sound excellent along with HQplayer. The other difference is that the Berkeley costs 2.5 times more. Ive also had the Nugent converter, ART Veloce, Wavelinks 96 and 192. Yes, I know that my DAC must suck if a converter can make it sound better than asynchronous USB. :-) Every dac uses different methods to attenuate jitter. Therefore, I am not surprised there is so much disagreement.

 

OK, in the matter of full disclosure, and honesty, I spent time with The Solicitor, the other night. Yes, the "Berserkely" sounds good. A fair comparison, 44 kHz to 44 kHz would be the only true test. But, in his case, he has this really neat s/w package, that allows him to tailor the play-back sound, to either correct for its flaws, or suit his tastes. In any case, it is neat s/w, and he gets good results with it. For him, the "Berserkely" is a good option.

 

No idea how much the s/w costs, who makes it, or where to get it. Worth looking into.

 

For those of you with Redbook only................and no AES/EBU..............

[bhobba]

I know.............I'm rotten.

 

No Pat - you are not rotten.

 

And there is a very well known guy out here in Australia, Joe Rasmussen, preaching exactly the same thing - its very low frequency jitter that is the thing.

 

I dont have any problem with this - the problem I have is this dismissiveness of subjective listening tests as worthless with statements like:

 

'Another thread down the mystical sewer pipe. At some point, reasonable people will draw correlation with magnetic fatigue fighting jewelry and the like.'

 

Thanks

Bill

[Blake]

For those of you with Redbook only................and no AES/EBU..............

 

Who you gonna call? Hint, the answer isn't Ghost Busters......

[tpaxadpom]

Pat's original converter is one of the best converters I've measured jitter wise (50Hz - 100kHz bandwidth for what it's worth, 44.1kHz only as it doesn't support other sample rates). Too bad it didn't work in my system at the time and I preferred Offramp 4 even though it wasn't as good on the test bench.

[ar-t]

No Pat - you are not rotten.

 

Yeah, I am, when it comes to the burr under my saddle, concerning a certain troll.

 

And there is a very well known guy out here in Australia, Joe Rasmussen, preaching exactly the same thing - its very low frequency jitter that is the thing.

 

I dont have any problem with this - the problem I have is this dismissiveness of subjective listening tests as worthless with statements like:

 

'Another thread down the mystical sewer pipe. At some point, reasonable people will draw correlation with magnetic fatigue fighting jewelry and the like.'

 

Thanks

Bill

 

 

Well, jitter is not a well understood, by the average listener, and their case is not helped by questionable claims by various manufacturers. Add on the fact some folks talk about jitter, at word clock frequency, and some of us use the bit clock frequency. That is how you get confusion that "2 uSec is inaudible", vs "Yeah, well we feel 1 pSec is too much." When you "normalize" the two, you find there really is more of a convergence than some lead you to believe. (Problem is some of those preaching the other numbers are so smart that they believe they can continue onward, in their close-minded approach.)

 

So, unless you know the frequency of the tone that you are measuring, and the jitter spectrum, the numbers mean nothing. It creates confusion, and confusion leads to folks tuning out. Which in turn leads to the comments that you find objectionable.

 

Which is why we provide our data, in fancy plots, that clearly state all of the above. Whether they make sense or not..........at least you know what we are referring to.

[ar-t]

I would be very careful comparing jitter measurements without knowing how they were done and what equipment was used.

At one point in time I preferred one converter with measured jitter 10X higher than the other one. Placebo is out of the question as I owned the better measuring one.

 

Yes.

 

And what you are actually measuring.

 

The only place that really matters is on the output of the DAC.

 

Some of us do not design DACs. We design clocks and/or SPDIF "transports". So, that is what we measure.

 

Sure, we could get a DAC (any DAC), and measure what comes out of it, but that probably would not tell us what guys like us need to know, when evaluating design changes. Case is point..............the need to measure clock "jitter" (phase noise), down to 0.01 Hz. Once we stumbled upon that, and knew what "knob" to turn, it made a difference.

 

But, you guys will get little benefit from that.

 

All you need to know is that a truly low-jitter system will have very good imaging. "Perry Mason" can attest to how a good TX box allows the height of the image to increase.

 

No, I don't know why*............it was discovered, in listening tests, and confirmed on our measurin' gizmo.

 

(Yes, his "Berserkely" has a good image.)

 

 

 

* = You would rather I come on here, and make up stuff? I'll leave that to folks who sell cables.