LIST: DACs w/ word clock input (and AES)

Add the Metric Halo units to your list - the ULN-2 and ULN-8 both have word clock inputs/outputs and AES inputs/outputs.

I"m quite interested in the Zodiac models you mention above (as I suspect that it's clock might improve even my ULN-2). I definitely believe that the clock will prove to be one of the Zodiac's strengths (i.e., I'm not as interested in it's word clock input as I would be it's output).

The Zodiac clock input that would seem to be most interesting is an Atomic clock input, so that the Zodiac could eventually be upgraded to clock from the rubidium clocks (a la 10M).

BTW, most pro audio DACs/ADCs will have word clock and AES, so also look into Prism Orpheus, etc.

enjoy,
clay

I looked at the ULN2 when I was looking for a transport but I use Windows. Seems I could still use it although I might want 192kHz capability.

Has anyone heard the UA 2192? Not sure if it has wc input.

The Zodiac + doesn't have a dedicated word out, but it has that de-jittered AES passthrough I think. Is that what you do?

Thanks Clay.

apologies for assuming you have OS X capabilities.

You could use it - but could not set it up w/o access to a Mac - and so, should probably look elsewhere, esp. as you want 192kHz.

Re the UA 2192, check with audioengr (aka Steve from Empirical), I think he's got a lot of experience with this device. You can find him at his Audio Circle forum.

"Is that what you do? "
I don't currently use an external clock with the ULN-2. For the money, I find it's clock quite good, but now that it is the limiting factor in my system, quality-wise, I'm starting to think about upgrade possibilities. Since I'd still want it's ADC capabilities - I'd consider picking up an external clock IF that improved it's sound, despite not being a fan of such setups.

BUT, as Silverlight has discovered & reported, excellent external clocks can improve even world class DACs, such as the ULN-8/Amarra Model 4.

BTW, Steve Nugent / audioengr reported this type of setup (external clocks with even high quality DACs) as being a possible improvement months ago. I ignored it based on theoretical principles (and the fact that Steve's recommendations were a bit, shall we say, self-serving). It's time (for me at least) to reconsider.

cheers

I'm just not convinced that using an external clock is a good idea. It is my strongly held belief that you should have a high quality clock, with a decent power supply, sitting as close to the AD/DA converter chips as possible. Period.

Yes, there may well be more accurate external clocks than the one in your converter. But, getting that clock signal fully intact into your converter is fraught with difficulty. IMHO, if you're hearing an improvement with an external clock, then your internal clock wasn't up to the job to begin with...

The only thing that really makes sense to me is slaving your interface to your DAC, for which you simply need a wordclock output.

As usual, just my 2c.

Mani.

Well, the folks who benefit from external clocking rave about it online. Pro studio people who tend not to be as nuttier as we. Theoretically it could be difficult, but subjectively it seems to big making big improvements for some.

And I know Steve N. argues to get the clock source away from the PC/transport...

I was as convinced as you are until recently, and just to be clear all I've said is that it's time for me to reconsider (i.e., not assume that this belief is untouchable).

"IMHO, if you're hearing an improvement with an external clock, then your internal clock wasn't up to the job to begin with..."

I might have to disagree with this as an absolute statement - as evidenced by Silverlight's discovery that the Rubidium/Atomic clock of Antelope is/was an improvement for the Amarra Model Four, which has world class sound capabilities. :)

Apparently, a properly terminated 75 ohm BNC connection can transmit clock signals at a level of precision previously unimagined (at least by me).

And, of course, I'm under no illusions that the clock in my ULN-2 is nearly as good as that in the ULN-8/Model 4 - thus my interest in the Zodiac DACs as possible replacement, or possible clock. Try as I might, I can't seem to find a cheap PM Model Two on ebay or a'gon. ;)

clay

I wonder if the Modwright Transporter would benefit from this, and I will be sending my clock to a friend who has one.

I would like to get a Grace m902 for the headamp and preout, but no word clock input. Still, reclocking the AES16 can't hurt.

I wonder if the Antelope will be solid all around i.e. headamp, DAC, output stage....

Jude @ Head-Fi had a prototype in his system....I'm trying to squeeze more out of him.

I always remember hearing the above words spoken to me by my high school physics teacher. And I think they're worth remembering...

Even if you could transmit the wordclock perfectly from the outside (which is impossible), it would only be as good as the same clock sitting internally right next to the converter(s). Of course, if the external clock were substantially better than the internal one, then I concede, you'd have a point. However, I would suggest to you that you certainly wouldn't have a unit with "world class sound capabilities". How could you if its own clock were that bad?

I'm not suggesting that there isn't a place for high-quality external clocks. They're invaluable for the pro guys when they need to sync many digital units together.

Clay, just get a ULN-8... they're much cheaper than any PMII you'll find on eBay. But don't forget to buy an atomic clock for it... oh, and maybe a linear power supply... oh, and if you could find some decent true multibit converter chips, you may want to replace the stock ones... ;-)

Mani.

You could try running the ULN off battery like Red Wine audio offers. The MOTU Traveler is a similar design, battery for portable use.

I still think external and dedicated clocking done outside the PC makes sense. I've had a few recent experiences with EMI that my PC is spitting out. Certain cables were picking it up like antennae (PC disconnected and just cables from DAC/Pre to power amp), and the USB connection to my DAC picked up the same sounds...it's nasty stuff.

Isn't another primary benefit to separate the clock form audio data?

So your solution is everyone should buy a Model Two? Could you go ahead and have them not only build them again but buy one for me? Thanks. ;)

David, I'm through talking about the Model Two. Honest!

But I can't help myself engaging in a bit of friendly banter with Clay.

Mani.

I was hoping you would take me seriously Mani.... too bad. When is Clay getting his Model Two? ;)

"I can't help myself engaging in a bit of friendly banter with Clay"

:-)

yes, it's been enjoyable, but time to move on, as you said.

cheers,
clay

I'm looking seriously at the Zodiac+ and Gold now.

Much more expensive than the devices mentioned, but all the dCS DACs have WordClock inputs. So do most (all) of the Esoteric DACs.

Yes, I glanced over those and assumed they did. I haven't listed higher end models out of reach for me, but I'll add any DAC that has a word clock input to the list if someone lists it.

Anyone here heard the Lavry DA11?

thanks!
hifi

The Lavry DA11 doesn't have a word clock input AFAIK.

Yes, it does not. I'll start a new thread.

I am surprised a bit that Mani has difficulties in making his point. But maybe it needs somewhat more technical insight instead of "because manufacturer A does it, it should be beneficial" ? please let's think a bit ourselves.

First of all, a wordclock input historically comes from the pro world to align all the different devices. Nothing more (and nothing less either, because this is of utmost importance). Nothing more because Pro stuff doesn't claim to need good sound. And oh, before ppl start blaming me to be wrong on that, Pro stuff just *is* not for good sound, it is for making music, while some manufacturers go further and produce equipment for recording, which obviously is about good sound again (pick your own brand now, but Mani is not allowed to say one single word about his, haha).

Let's next hop over to i2s. You know, that protocol not made for outboard connections. And again, if I were you I would stay far from "but PSA and blahblahblah also do it SO it must be good". Why aren't we able to think : ... SO they don't understand ??

In between lines, I have to say (from Chris) that I have a vested interest here, because of the due Phasure NOS1 D/A converter. Ok, done. :-)

Why aren't we capable of believing Gordon on this matter, and next "know" that too long i2s lines impeed for (additional) jitter. Or, why wouldn't you believe yourself at looking at a scope and looking at the signal of the word sync (= word clock, LRCK) and bit clock, and see it degrade when the cables get longer. And not to speak about what they may pick up underway.

Now, we could say that i2s is a derival of the oscillator = clock which creates that (pulse) data. So, the clock itself runs at an even higher speed than what's derived from it (never mind this much), and the data line we talk about here is the wordclock. It determines when a one channel sample goes into our precious DAC chips. The wordclock is leading here (meaning all other "clocking stuff" is a derival from it, and it will contain more or less jitter.

Now try to visualize that an i2s wordclock line being longer changes the shape on the scope; would there be any reason the external wordclock line behaving differently - assumed it is properly (75 Ohm) terminated in the first place ? I don't think so. And thus it definitely deteriorates. But :

Back to the external (hence too long) i2s connections, manufacturers easily state it doesn't matter or ...
... or NET it works out for the better. But of course it can work out better net ! It just depends on the quality of the oscillator in the first place. Thus, supposed the too long line creates 5ns of jitter, what would be the problem if the intercal oscillator carries 100ns of jitter to begin with ? nothing much. And I even think the result will not be 100+5, but just 100 because it kind of overrules (with side effects).

But now let's turn this around a bit :
Now I have an external clock with 5ps of jitter, and I use the wordclock connection and hope for improvement. Et voilá, there *is* your improvement, because your original 100ns of jitter dropped to a virtual 5ns. Say, 20 times better !

Sadly, here is the thinking error (if not obvious to begin with) :
Now I have an oscillator with 10ps of jitter. Mind you, worse than the external clock (which is 5ps). Sadly, at using the external clock I'll loose it on the connection, which just impeeds for 5ns, and my jitter gets 1000 times worse of it (1000 times may not be the correct expression because it will (need to) be on the dB scale).

Need I say more ? it just depends on the native jitter quality of the internal clock.
But let me add this : If you'd go to a self respecting "clock upgrading" company (and why not use Guido Tent as our example), and you ask how far away the replacement clock is allowed to be from the original position, the answer is "millimeters" and explicitly not "centimeters". Uhm ... let alone one meter which is what the external clock would imply (almost).

Lastly, notice that it is somewhat more complicated, because with any normal DAC used for a PC, the DAC chips will not be fed directly by the oscillator, which is because there will be other devices in between like SPDIF to i2s, PLL clock recovery stuff, and it is the most easy to have a net result of over 1ns of jitter, no matter the oscillator carries 3ps only. So, now YMMstarttoV because the incoming external wordclock is not only subjective to the length of the line, but also to the intrinsic jitter *after* it, which is a fixed parameter (for any one DAC).

Just my thoughts !
Peter

Gang,

Understand that using a word clock input is NOT a good idea!!!!!! Any time a DAC has to match any clock this means the DAC has to have a movable Master Clock. Well that or the easy way out and use an upsampler but then in that case why even bother.

But anytime a DAC has to match this Word Clock input the Master Clock then has to be a compromise. Think of it this way... what is audio related jitter error? It is the moving of the audio clock system in a way that creates errors on the output. WELL if you are matching the Master Clock to the Word Clock input then in a sense you are just adding jitter to the system.

Also why even do this... Word Clock input is used in studios to align multiple digital devices to the same clock. This is a very good idea.

Using it in your home system is not.

Thanks
Gordon

I agree with you on this one, totally.
Listen to the guy, he knows what he's talking about here.

For better or for worse, I use a hybrid digital-analog playback system a la PureVinyl; mainly for archiving out of print material etc., but also for listening.

So maybe my system in particular would benefit from a word clock?

Equipment

Nitty Gritty RCM Mini-Pro
Clearaudio Innovation Compact AMG Wood 70mm
MG1 Airbearing Tonearm (directly wired to AEA)
Grado Reference1 (Statement .5mv)

AEA Big Ribbon preamp (flat gain) 35K input impedance
Mytek 192 ADC
Lynx AES16
Black Lion "Macroclock" (modified MKII Microclock)

Cardas nuetral ref./silver litz
Recording: Wavelab 6
NR: Wavelab 6 & iZotope RX
Dither: Ozone 4 Mbit+

Word Clocks: BNC
Digital: AES

In this case, archiving is done with the Mytek slaved to the Black Sparrow as is the Lynx.

Playback involves monitoring a "wet" signal passed i/o the system via ASIO with Samplitude (RIAA is applied with a 96kHz VST filter based on R. Orban's math for PureVinyl it is NOT an EQ).

What I normally do as monitor "wet" and record "dry" simultaneously. I later do mastering (e.g. RIAA, manual click removal).

Steve at Empriical has commented that getting the word clock generation out of the PC is always a good idea, but some interesting points raised here which are admittedly over my head in many ways no matter how much I actually seem to understand the crux of Peter and Gordon's points.

I also feel ProAudio is getting knocked too much; just because industry standards may not be what we perceive to be "audiophile grade"...this is where what we listen to comes from. Mark Knopfler's recording process comes to mind. Have you heard the fidelity of his recordings? It's a grand overstatement to think they are not focused on sound quality, but just making music.

"Today it seems that everybody tries to make a record that’s squashed, and the warmth is taken out to make it stand up on radio. I think you can accomplish great radio records and still be able to listen to them on great playback systems in good quality environments. That’s what I try to do. It just takes a little more effort. It’s easy to squash a record and make it really loud. "

http://www.premierguitar.com/Magazine/Issue/2009/Dec/Producer_Chuck_Ainl...

Chuck Ainlay

Gordon said "Also why even do this... Word Clock input is used in studios to align multiple digital devices to the same clock. This is a very good idea."
Surely in a computer system using a DAC with AES input you ARE synchronizing two digital devices?

I know you would argue that using an asynchronous interface (such as your USB devices) is the ideal, but these are very limited and some people do prefer the sound from other DACs (yes I know thats an amazing thought!!). Other DAC manufacturers have different thoughts to yours which don't make them bad DACs!

Eloise

I would love to use a Wavelength DAC but I can't as most USB DACs don't allow for the operation of Samplitude's hybrid monitoring, which doesn't seem to work in WDM or MME modes, only ASIO.

I don't use ASIO for latency, just because it's the only thing that allows me to monitor/apply RIAA in realtime.

hifi

Far from being an expert, but it seems pretty consensual to say that:
- The more you have elements/steps in your digital chain the more you have jitter
- Unless you have a far superior external clock compared to your internal clock, it is likely that the interior clock will do a better job as no extra jitter is introduced by an external connection.
- External clocks are used in professional studios because there can be a lot digital devices between the source and amp, sometimes not working at the same frequencies: synchronisation is not optional.

From there it's about finding the right balance.
- I'd think that if you have only one device (source+DAC), you would need a rubidium clock to make a difference and, even then, you may possibly not hear it.
- If you have 2 devices, it may useful to use one of the two as master clock, not so much to improve the clock but to improve synchronisation. the idea of asynchronous usb connection between source and DAC is similar: it is about having the best clock used as masterclock. Here again, to have a clock improvement you might need to look for Rubidium devices.
- If you have more than 2 devices (I have for example a source, a DEQ and a DAC) I believe it starts to make sense to synchronise these devices with an additional clock. Am I certain to do the right thing? No, but I have the clock now I'd better use it!

The basic problem with digital audio, be it from a transport or a PC is that you have the clock that drives the DAC, and the clock that drives the audio. As I have said until everyone here is bored, the optimum solution is one where the DAC clock drives the source, as the critical point of the clock is at the precise moment when the signal transitions from the digital to the analog domains.
However, these solutions are rare, or tricky to configure - especially for sources.
So, the DAC needs to synchronise it's clock with that of the source. There are a number of options here:
(a)use an ASRC to manipulate the data between the clock domains
(b)use something like I2S, where the DAC is driven directly by the clock in the source - unfortunately, the source is too far away, and the standard is not agreed in terms of an external interface. I would contend this increases jitter rather than decreasing it
(c)SPDIF is self-clocking. Use the extracted clock to drive a PLL to drive the DAC clock. SPDIF is designed explicitly for this purpose, so it can be made to work really, really well, but the problem with SPDIF is that if you're not very careful, the extracted clock will be modulated by the data encoded in it - this is known as data-induced jitter
(d)the scenario discussed. In this topology, the data (audio) is sent by SPDIF, but the timing is driven by a wordclock, which doesn't carry any data ( audio ), so cannot cause data-induced jitter, and is easier to work with as well. Additionally, the wordclock signal is a defined standard, and again, uses a PLL to reduce jitter caused by the length of the cable.

hope this helps,

your friendly neighbourhood idiot

Your thinking is not wrong, but maybe back to the basics :

Surely in a computer system using a DAC with AES input you ARE synchronizing two digital devices?

Not different from SPDIF IMO, athough the connection will be electrically better. It would be different (and maybe you wanted to say that ?) if the soundcard has a wordclock-out, to connect to the DAC's wordclock-in. But there you have the cable length problem again.

I know you would argue that using an asynchronous interface (such as your USB devices) is the ideal, but these are very limited and some people do prefer the sound from other DACs (yes I know thats an amazing thought!!).

... which still doesn't justify a worse means of clock connection.
IMO etc.

Peter

Sorry Peter,

you've lost me - I presume you're talking about your DAC?
USB? SPDIF? AES?

I'm sure I'm being an idiot again,

your friendly neighbourhood idiot

Mr. Idiot....:-)

I always appreciate your posts. In a set up like mine where I have a Berkeley Alpha DAC (with no word clock output or input) fed by a Lynx AES16 card (which does have a word clock input), what would you consider to be optimal set-up?

My experimentation has shown that using an Antelope DA in between the source and DAC improves sonics even though the DA is not reclocking/dejittering the AES datastream, but rather just buffering it and providing noise isolation. The entire soundstage was rendered with less smearing - perhaps this is caused by reducing the data modulated jitter you mentioned or perhaps it is a result of reducing noise. The fact that Berkeley themselves will be coming out with an AES reclocker/noise isolator later this year is telling. I mean why do this unless it improves sonic performance right?

Some have noted that using an external clock for the Lynx improves sonic performance, but this does not address noise isolation. Antelope will be shipping their Zodiac Plus in late April which will, among other things, dejitter/reclock an AES input and pass it back out. It would seem to me this might be the best approach. The ULN-8/Model 4 also provides this capability, albeit at a higher price point. I know there are various firewire and USB to AES converters which provide similar functionality.

Personally, I would think for the above reasons and others, that a properly designed and executed async interface would be preferable and superior to AES. Although Berkeley claims they did not want to build such functionality into their DAC as it would cause noise that would degrade sonics. Thus they will be coming to market shortly with a USB/AES converter. Interesting....it seems other DAC manufacturers have figured out how to include such functionality into their DAC's.

Thanks for your thoughts.

David

Now for me to actually contribute something to the topic, a DAC with WC inputs:

Apogee Rosetta 200
Apogee DA-16X
Lynx Aurora 8
Crane Song HEDD 192
Lavry Blue (Black/DA-10 model but rack mountable with ability to add extra channels of AD or DA)
Burl B2 Bomber (great analog sound for a DAC)
Creamware A16 Ultra
DAD AX24
Prism Orpheus
Prism Dream DA-2

I'm sure I'm forgetting some important ones but these are all great converters, the bottom of the heap being the Lavry Blue, which is still a very solid converter.

idiocy - guaranteed!

Hi,

there are two things to consider with any clock, namely: low frequency stability ( perhaps regard this as "drift" ), and high-frequency stability ( commonly aka "jitter" )

In your setup, you have very limited ability to modify the high-frequency effects of the AES stream going to the DAC, but the LF stuff ( or absolute frequency ) is very much where the new clock will have an effect - YMMV as they say.

I wish you well, there really is no substitute for listening,

your friendly neighbourhood idiot

Thanks for the response. Interesting that you used the term "drift" for low frequency stability. Good word. That's what I hear when I don't use the Antelope DA. Images "drift" causing them to be less than precisely rendered - bass sounds fat and images on the soundstage are fuzzy.

A further question. Can a reclocker "fix" the drift and jitter of a less than optimal incoming AES signal OR is it critical that the source device (in my case the Lynx card) be supplied the most accurate word clock as possible?

Thanks,
David

I am sorry my super-statement didn't come through. So, again :

Eloise :
I know you would argue that using an asynchronous interface (such as your USB devices) is the ideal, but these are very limited and some people do prefer the sound from other DACs (yes I know thats an amazing thought!!).

Peter :

... which still doesn't justify a worse means of clock connection.
IMO etc.

Of course it all depends on how I interpreted Eloise's text, which is always a dangerous thing, Eloise being my personal sparring partner here (at least that is how I appreciate her, and it often helped me). So (IMO etc. :-) this is Gordon with the implied (!) claim of async being better always, Eloise pointing out that people may prefer other DACs for their sound etc. However, since the subject of the thread is - or may be seen with async in the mix as : "If you don't use async, then better connect the clocks", I tried to say : "but this still doesn't justify the means of wordclock connection" (that being worse than SPDIF, IMO etc.). And of course this is in the context of my own earlier post.

But you don't need to be an idiot in order not to understand my posts ...
Peter

Eloise,

Surely in a computer system using a DAC with AES input you ARE synchronizing two digital devices?

Well AES is a form of SPDIF which uses the XLR connector that claims 110 ohms impedance (not true). The question is why would you want to SYNC a dac to the computer? Yes I could see in an audio application with say a software xover and two/three dacs that using a Word Clock input maybe beneficial. But not really... In a studio using non-like AD converters is really were you need a Word Clock input so the output of said devices is synced up.

But in audio the use of Word Clock is a waste of money. Sure it may change the sound it maybe even better.... but if it is then that dac really maybe suspect to other problems.

See if you use Word Clock synchronization then you are basically asking the dac to sync it's internal Master Clock to the incoming Word Clock input. Ok so let's look at this again.

Word Clock is usually specified as the sample rate and runs at let's just say 44.1KHz
Bit Clock is 64x faster than Word Clock and gives the data stream it's clock with 32 bit samples for L and R.
Master Clock is usually 256x, 512x etc... or 4x (256x) or 8x (512x) the Bit Clock.

Ok so we have this input Word Clock which applied to a PLL with the Master Clock derived Word Clock to determine the overall speed of the Master Clock.

Remember people dividing clocks creates jitter. Between 3dB-6dB per every division of 2. But when we create an MCLK from the input Master Clock we are not only introducing jitter to derive our local Word Clock but also in the other direction to create the Master Clock.

This is why this is a needless thing to attempt to do.

Eloise... I understand your pain and love for your favorite dac. That is why I am working with a ton of companies to solve that problem as well as the soon to be released WaveLink HS which will be a USB to SPDIF converter.

Hifi,

I would love to use a Wavelength DAC but I can't as most USB DACs don't allow for the operation of Samplitude's hybrid monitoring, which doesn't seem to work in WDM or MME modes, only ASIO.

Why would my dacs not work like any other audio device you are working with? They use internal drivers which should mean they would work with any software not just ASIO.

Thanks
Gordon

David,

A further question. Can a reclocker "fix" the drift and jitter of a less than optimal incoming AES signal OR is it critical that the source device (in my case the Lynx card) be supplied the most accurate word clock as possible?

All jitter reduction works like a low pass filter. Nothing can really fix jitter, it can get rid of some of it but it cannot get rid of all of it.

This is why it is important to remember the differences between an Asynchronous connection and a Synchronous connection. With Async you have only the intrinsic jitter of the conversion of data to say I2S and the DAC. With Sync (Adaptive, SPDIF etc...) you will always have link induced jitter that will have to be solved. Ounce solved, some of this jitter will be added to the intrinsic jitter that the Async system has and therefor always will be higher than Async systems.

This is why I always talk about "why fix jitter". Any device that has to do that will not be able to get rid of all the jitter and that will be added to the intrinsic jitter of the dac chip and the local interface.

Thanks
Gordon

Well,I need to choose ASIO for the driver protocol in Samplitude, but when I do so I am locked to a particular driver and device.

When I had my Musiland and HiFace here (usb transports), I could choose ASIO for Musiland but how would I route my ADC and Lynx into Samplitude. When I choose MME or WDM I can see all playback and recording devices, and the ones I tried did not allow for any type of "live monitoring"...I would get no output with the USB playback devices. Maybe yours would work. I'm not sure.

I just figured since I already use the ADC in a live monitoring situation (like a recording studio) that an external word clock would be better suited, and thought that AES for audio data and BNC for word clock would be the least compromise.

I may pick up a Proton for my office though ; )

All makes good sense to me Gordon. I think this is the first time, I've seen the relationships between the different clocks in a DAC explained. At least where I can understand it.

Thanks

Can't you use ASIO4ALL?

And, just to re-iterate: the DAC being the master is the best topology in terms of jitter. Next is an AES/SPDIF for audio, with a wordclock for timing, followed by using the AES/SPDIF for timing.
The quality of each of these approaches will be determined by the quality of the design and components used.

i.e. There CAN be a reason to use a wordclock to improved the sound.

your friendly neighbourhood idiot

I may have tried that, or was just using it for HiFace.

will check tonight.

Blue Jeans Cable responded to me about Dsub:

"Generally speaking, the larger the "pass-through" distance, the larger the
connector will deviate from a "true" 75-ohm. So, as an example, RCA
connectors have a longer pass-through distance than a BNC (which uses the
center conductor as the BNC "bayonet"), and therefore the BNC has a more
accurate 75ohm impedance.

As with most D-sub connectors, the soldered conductors are only 4-5mm away
from the end of the conductor pin, and will only deviate slightly from the
75ohm coax used in the assembly."

Has both wordclock and AES.

Has both wordclock and AES inputs.

hifitubes, I take it the same would be true of AES correct? The XLR connector imposes a reasonably long pass through distance and therefore will deviate from the 110 ohm spec. Is there any studies you are aware of, formal or informal, that compare the sound quality of AES XLR vs SPDIF BNC? I just tried a Legato USB/SPDIF BNC in my system feeding my Berkeley and compared to my Lynx AES16 clocked by a BLA Mk2 word clock with a very high end AES cable...the Legato was better. Since the Legato has galvanic noise isolation and uses async USB to extract the digital data from the computer, it's of course hard to know what is causing what. I'd love to try an async USB - to - SPDIF BNC AND AES XLR converter for that reason. I don't think the new Wavelink does AES and similarly unsure if the new Berkeley box will do SPDIF.

Too bad your Berkeley doesn't have WC input so the MKII would have been Master of the DAC + Lynx. I'd like to know what the results from that comparison was; would be very interesting. The Legato is certainly a fantastic piece.

I agree davidR. It's interesting to me that the BADAC design goes against the grain of prevailing digital audio wisdom in a couple of areas. First, as you noted, they don't provide a word clock in or out even though they know from designing the Model 2 that it provides a superior sounding AES interface. Second, they chose not to offer an async interface - perhaps the technology was too new when they designed their DAC.

Right now, based on price/performance, given my existing set-up I would use the Legato for 16/44.1 and keep the Lynx AES16 for non 16/44.1. But, with a slew of new USB/SPDIF-AES converters coming out I guess one should wait for the dust to settle before deciding.

Berkeley is supposed to have Async USB to AES converter coming out this year. In my opinion, their reason for not having the USB interface built into their DAC is just spin. As if using a S/PDIF / AES input is the better way to do this.

Earflappin, we are definitely on the same page. Steve Nugent's new Off-Ramp USB interface is coming out soon which should be a top dog in the USB interface explosion. It's been revamped with full 24/192 Async USB, he found a way to fit his best clock (ultraclock) into the unit, fully automatic sample rate switching and is even offering an infared remote; with the options of spdif, AES, Toslink, and I2S outputs. The usb input provides galvanic isolation as well with options for beefy power supplies, Steve claims the expensive USB cables offer no improvement over his Belkin and I think he's tried up to the Nucleus line. Should be an interesting contender, and I guess it should be for it's price but with computer audio in it's infancy and his limited R/D budget I think what he's doing is pretty incredible as are many others in this world of digital reproduction.

Anyone know if the Antelope DACs will use async USB?

If I pick one up I will demo the USB vs. the AES input as directly clocked by the MKII.

I'm still tethered to AES because of my vinyl setup but maybe the Zodiac will work with ASIO4ALL in Samplitude to do realtime signal processing for digital RIAA.

I'm waiting on an e-mail back from Antelope about Async.