Thanks for a nice review, Happy.

It is interesting to know when to choose a synchronous system or an asynchronous system.

If the DAC (the S/PDIF receiver) can take an external master clock word (for synchronous reclocking), would this offer the same result as what the Antelope DA reclocker does ?

BTW, I came across an interesting article Firewire Sampling Jitter

Hi Paul,

The better the feed the better the performance of the DAC should become a wide-known fact now. I was so surprised in the sonics I heard from my OMZ DAC/PREAMP fed by the Lynx AES16e card in my PC.

> Subjectively my Benchmark plus Reclocker (total approx $2k) is 75+% of my Alpha ($5k).

I wonder how much performance gain (subjectively) in your Alpha from the Reclocker alone ?

Thanks.

Thanks Paul
you are of course 120% correct in all you say. I misinterpreted your post. My apologies. What I thought you were saying was - "forget an Alpha, just buy a benchmark and reclocker." - what you were saying is, I think, is this is a great device for improving mid range sync dacs.
Cheers
Andrew

Let me preface this by saying that my Amarra experince is not the consensus on CA:

The reclocker (so far) has been the biggest single improvement that I've made to my main listening system. It widened the sound stage dramatically and focused the instruments - my wife could not believe the difference.

Having said that I have 2 systems outlined below. In my main system there is no discernible difference between itunes playback and Amarra playback - I choose to use Amarra as it handles the various rates. I am in the minority here.

Last weekend I tried Amarra on my 'office' system for fun. Boy what a difference it made! - it removed the harshness of the music.

So I set about comparing my two systems. The conclusion I have come to is that my media room system MAC pro is very 'clean'. No excessive processes executing - mimimal background tasks - no monitors - no multiuser accounts no drive fragmentation- whereas my office system routinely has 100+ processes running.

I dived into the kernel and found playing the same song on two systems (identical macpros - identical processors - same processor batch even, and identical memory - identical OS's) that itunes had 40 threads on my office system and 21 on my media room i.e. under the covers they are doing different things. I conclude that itunes works ok if nothing gets in its way - other scheduled processes whereas Amarra works properly - meaning better kernel priority's.

So far my experience is that hypothetically given only $1k (by the wife) to spend I would reclock (for signal integrity, isolation and giving me a longer cable length to the computer) and keep a very clean computer system. Of course I would then not hesitate to make a new 'case' for Amarra.

/Paul

To answer directly:

An async system is a much better delivery system than sync. Having said that the mechanism of data transfer can matter e.g. USB (shared) is not as good as Firewire (essentially channelised) - there is a QoS spec, flow control issues to deal with. I have several patents in this area.

However... for the audiophiles the DAC process matters i.e. filters, sampling etc... Arguably the Audiophile DACs are still very sync based - the 'lesser' Studio Type DACs e.g. RME have async ports. I think this is changing or has changed - I've not (yet) experimented with Wiess, Sonic etc.. but technically I think they have a significant physics advantage - reading clay's posts I think he has great insight into this area.

Some Audiophile DACs have a clock input - I tried to convince my wife to allow me to get the Atomic clock from Antelope into an OCX into the Alpha (but the Alpha doesn't have a clock input....) There is a thread on CA which talks about Alpha's decision not to add a clock to their DAC.

/Paul

Thanks for your insight, Paul !

Some months ago, I had been thinking to get a decent CD transport after borrowing a $$$$ unit from a friend of mine. The Lynx AES16e changed my mind looking at the PC transport path. Thanks Chris for the great collection of knowledge here !

However, the Lynx still doesn't offer the "best" sonics I wish to hear in my system, compared to a modded transport I've auditioned. The question would be whether it's a fault of the digital transmission or the DAC. Consequently, which improvement path to take ? Is this about the jitter "thing" ?

Your personal observation indicates the benefit of "transmission" reclocking. There are a bunch of such devices, but I personally think the USB reclocker would be the most convenient for typical PC audio setups. I wish a quality USB reclocker should be priced below $300. ;-)

Some friends of mine believe synchronous reclocking is the only answer for the best sonics. Perhaps, USB async DACs would be the final winners. ;-)

A DAC I own has a decent (very transparent) analog output stage which has a significant impact on the sonics as well. Bob's BADA has such custom discrete output stage and a custom clock.

http://www.computeraudiophile.com/content/Fireface-vs-Lynx-AES16

I don't mean you should do a mod, but the next bottleneck could be in the analog section. Should you proove this to your wife. ;-)

I think the most common suggestion would be to not use an external clock to clock per se, but to reclock the digital signal. The Antelope Isochrone DA in this application takes the digital signal from the Lynx and then reclocks the output to have less jitter. The Lynx doesn't necessarily take any signal from the Isochrone. This is similar to the Apogee Big Ben which is a master clock, but also has the function of reclocking digital signals, or the Genesis Lens or Empirical Pacecar which just reclock a signal. So, yes you have many options other than the Antelope, but I don't know of any comparative reviews upon which to base a decision.

Hi Guys - I'll have an Antelope Isochrone OCX master clock here next week. I've listened to systems with this clock before and liked the sound. Now I'll be able to clock my system in numerous different ways and report back my findings.

Link to the Isochrone OCX page

I own the Black Lion Microclock MK2. It's the best clock out there for the money in my opinion. I prefer it over the Apogee Big Ben but that's in my setup. Matt Newport, the founder of Black Lion Audio, is an extremely helpful guy and truly cares about his customers. For instance when I bought my Microclock last December they forgot to include my standard $25.00 BNC cable in my package; after shooting them an e-mail they shipped me their $50.00 premium BNC cable at no extra cost 3 days later. Talk about customer service. I wonder if they could offer a trial for the Microclock? For $475 it's not a bad deal.

For fun:

To test the reclocking I swapped out the MacPro(SSD)/Lynx for an (direct connect) Ethernet connected Sonos box. The music server is in my office (another room on the network).

I fixed the output (meaning that the sonos box did not sample alteration) then fed the output into the reclocker.

I played HDCD music - nice blue light on the Alpha DAC (some believe that this means the samples are reaching the DAC without any alteration).

Jitter should be controlled with the DA.

This is essentially an async like system with Ethernet replacing USB/firewire.

It performs at 90%+ of a my computer fed system below. My surprise is that it doesn't perform at 100% of the system below - However for people who don't want to go the whole 'computer' in the media room root - this is very very good.

A downside is that you can only play 16bit/44.1 sound (other files get adapted down).

The sonos can be controlled by ipod/iphone. The player avoids the use of itunes.

There may be other Ethernet/spdif solutions I have not tested these - I have tested the Sonos.

/Paul

Their is another choice out there for hi end clocking and re-clocking, Grimm Audio.

http://www.grimmaudio.com/cc1grimm.htm

I have not had a personal opportunity to use one, but am familiar with their work in general and regard it well. Their white papers are worth reading as well.

perhaps if I post here someone will try it out and report back!!

they come from the production side of the business (like myself) and are interested in raising the production quality of recorded media.

Alan

I see that the DA is a "distribution" system -- but is it it's own clock, or do you need an external one?

I'm interested in the "re-clocking feature", specifically, fwiw. I take it that this is the only product in this vendor's lineup that offers that feature?

Also, does anyone know if the Zodiac is going to offer re-clocking on it's inputs?

The DA will extract the clock from an AES or SPDIF input and redistribute it. I have in the past fed it with a Sonos output, a CD player output and a Lynx card output. Without looking at the circuit I'm guessing that the Jitter circuit is averaging the clock signal over a period of time then outputting a low jitter clock with that freq - there are several technical ways to do this.

One can feed the DA with an external clock e.g. OCX or Black Lion - I may try this is subseqent months. The downside to this is that one needs to alter the clock source if one listens to a sound track with a different freq. By locking onto the AES signal from the lynx as one changes the sample freq by switching from track to track in itunes the DA will lock on to the sample freq of the current outputed track.

The DA 'function' appears on several of the Antelope product.

As 'earflappin' points out it is disappointing that reclocking is necessary.

/Paul

"I guess it is a bit puzzling that a fairly expensive DAC such as the BADA needs a reclocker."

Hi Encore - I don't agree with you on that statement. I think many DACs in every price range can benefit from a good reclocker. These DACs don't need a reclocker to perform great, but it may help depending on the source the DAC is fed. I know there are other computers & interfaces that perform very well and may minimize the effect of a reclocker. Thus reclockers have varying benefits based on a combination of the DAC and the source.

so you say, if I get a weiss afi1 interface, then I may not need the reclocker? that would be the preferred option: costs less (especially if i add the price of a lynx) or at least the same and i have a good, jitter free signal from the beginning (and my computer is electronically separated from the dac). or am i wrong somewhere?

Encore says:
"I guess it is a bit puzzling that a fairly expensive DAC such as the BADA needs a reclocker."

CHris says: "Hi Encore - I don't agree with you on that statement."

I'll agree with Chris, and pile on a bit. By all accounts the BADA doesn't need a reclocker to sound great. With evidence amassed in it's favor, one would have to acknowledge it's place as the top of the heap of the 'legacy' DACs (dCS priced gear notwithstanding).

That the BADA might benefit from a reclocker has little, if anything, to do with Alpha's capabilities, but seems to be a practical limitation of the S/PDIF type interfaces (in this case, AES/EBU), at least according to people way more knowledgeable than me on this matter.

clay

Agreed,
"I think that DACs of the future will benefit less and less from a reclocker, as I think that much of what the reclockers do will trickle down into more affordable DACs."

There is a belief among at least some engineers that an external clock can never reduce effective jitter at the DAC to as low a level as a local clock. No matter how accurate the external clock, it's accuracy will be diminished by nature of the process for syncing the DAC's clock, i.e. communication is required, cables are involved, etc.

clay

I had an e-mail exchange with Antelope. I person I interacted with said the DA DOES NOT de-jitter/reclock the AES input, only the WC inputs. The AES input is buffered and retransmitted out the pass through. Therefore, it would seem the value being added for those of us using it between our Lynx AES16 and Berkeley DAC's is one of noise isolation. Antelope did say that their new Zodiak line of DAC's WILL dejitter/reclock the AES input.

As an aside, Berkeley told me they regard the Lynx AES16 as having pretty low jitter and predicted the greatest value add of the DA would be noise isolation. Interesting. In any case, the sound quality improvement provided in my system is significant and unless someone knows of a cheaper way to get noise isolation the DA is staying in my system.

BTW, I contacted Grimm Audio and their CC1 DOES reclock the AES input so I might give that one a try as well. No word from Sweetwater or Antelope as to when their Zodiak DAC line will ship.

Encore, good points. I've tried the Berkeley with Toslink, Coax and AES and it definitely sounds its best with AES. I've not tried a Toslink jitter reduction device although I know designers who assert with proper dejittering/reclocking it sounds as good as AES. The Berkeley doesn't support ADAT. The next input they will support is asynch USB via a separate box which will also provide electrical isolation.

Personally, I believe asynch USB will become the defacto interface standard as so many devices support it. Firewire may have some technical advantages, but even Apple's support for it is lagging. From a design standpoint, it will be interesting as there are many designers who believe USB and FW interfaces are too noisy to be put in the same box as the DAC. They prefer a separate box with good electrical isolation features. Clearly others feel the issues can be addressed in a single box.

It's going to be interesting to see how the DAC industry unfolds. Until then, as Happy posted, those of us with existing investments in current DAC technology just need to optimize our specific performance variables as best we can. This forum is a great way of sharing that knowledge. For me personally, it appears that means investing in a device like the DA to get the noise isolation required for better sound quality.

Good point Scot. Not being an AES interface expert I can't say. I've got a Grimm Audio CC1 coming on Wednesday which is both a word clock and a true reclocker and I'll report back on how that demo goes versus the Antelope DA. Should be interesting as I will be able to try it as strictly an AES reclocker and as a word out clock to my Lynx AES16 card.

If the Antelope helps adding some level of isolation for the electrical connection between the computer and DAC (AES / EBU in this case), I don't think the Power Plant Premier would yield the same effect. It may help in isolating source components from the garbage that the PC might throw back into the power lines though.

Alan

And what do you think about the USB2-->AES3 box?

Depending on the price it could be a cheaper alternative to the Lynx Aes + Antelope DA combo, I'm wondering if it can even improve the level of performance or with the BADA there will always be an unbreakable wall of 50ps jitter, due to the AES input

http://www.computeraudiophile.com/content/Reclockers#comment-33723

riderforever

This should work well as long as:

(1) The USB is async

(2) The PSU of the box is well designed (avoid pollution)

(3) A WC input would be valuable.

At the end of the day the DAC vendors will control their internal jitter and will differentiate on that basis - many of the comments in CA here revolve around providing an engineering separation between the source of the bits - an electrically noisy computer and the ultimate conversion to analog.

I believe, strongly, that the computer bit is trivial, creating a DMA from hard drive to digital interface is a high school project. The complication is in the quality of the analog conversion and ultimately the preamp.

Having said that one should give the DAC a fighting chance and not pollute the inputs with environmental problems.

/Paul

Happy, like you I've found the Antelope DA audibly improves sound quality in my BADAC-based system. However....

Antelope has twice confirmed they do not reclock/dejitter the AES pass through and I have now been able to confirm via Lynx that they use transformers on their digital outputs. Wouldn't this provide electrical isolation from the PC environment thereby negating any further isolation benefits of the DA? Do you know if the DA provides galvanic isolation of the pass through?

Scratching my head on this one.....Thanks.

...four years ago we had really a great time here in Turin, I wish you the same now in Vancouver!

Back to the topic, from the Lynx AES16 specs I read:

• Eight stereo inputs and eight stereo outputs 24-bit AES/EBU format, transformer coupled

Also the RME HDSP9632 provides this "feature":

• AES/EBU: 1 x XLR, transformer-balanced, galvanically isolated, according to AES3-1992
• output voltage 3.5 Vpp

So how is it possible to hear such improvement only because of a further isolation? Isn't the soundcard isolation enough?
Maybe a RMAA analysis with and without the Antelope DA in place could help in understanding what's going on...