[weff]

Does the e20 from ExaSound have a FEMTO clock?

I am puzzled as to why you think it has better specs than the Auralic:

With Sanctuary Audio Processor as heart, AURALiC introduces several cutting-edge technology for VEGA: Megahertz upsampling algorithm up-samples all PCM music to 1.5MHz in 32bit; Femto Master Clock provides an ultimate clock precision with jitter only 82 femtoseconds(0.082 picosecond). Binding with other AURALiC's patented technologies such as 'ORFEO Class-A module' and discrete 'Purer-Power™ solution', VEGA will bring high resolution music playback experience to climax.
b]

The exaSound e20 and the AURALiC VEGA are extremely close in performance - just look at a comparison of more of of the stated specs.

I really don't think you can just look at the master clock jitter and not compare the rest of the performance figures.

e20 Upsampling  Not stated             VEGA Upsampling 1.5 MHz.
e20 master clock jitter 0.13ps          VEGA master clock jitter 0.082ps
e20 THD 0.0002 %                          VEGA THD  0.0003%
e20 Signal/Noise 128dB                   VEGA Signal/Noise 126dB
e20 IM distortion 0.0000079%          VEGA  Not stated
e20 Channel separation 130dB          VEGA  Not stated
e20 Dynamic range Not stated           VEGA  130dB
e20 Inputs 1xcoax,1xtoslink,1xUSB   VEGA  Inputs 2xcoax,1xAES,1xtoslink,1xUSB
e20 Outputs XLR, RCA, headphone    VEGA  Outputs XLR, RCA

I have no doubt that the VEGA IM distortion & VEGA Channel Separation will be close to those of the e20 - but if you look at the THD and Signal/Noise which are equally as important as the master clock jitter then the e20 is "superior".

While exaSound may not have the pedigree of AURALiC the e20 is clearly a well engineered product (as is the VEGA) - and in some aspects the e20 is "superior"  just as in some aspects the VEGA is "superior". The VEGA was designed as an audio processor - hence more inputs and no headphone socket and costs more - while the e20 is a DAC with less inputs and costs less.

I don't know whether the e20 has a FEMTO clock (now a commonplace bit of silicon) - but one has clock jitter 130 fs versus 82 fs - both very small numbers - and both very good figures. It would be interesting to know the e20's upsampling rate so as to compare that with the VEGA.

In the context we are talking about though with these vanishingly small numbers - in the real world the end result any noise/distortion will be so inaudible that a comparison between the VEGA and the e20 should really be a tie.

Both devices support the same capabilities PCM 384K/32 bit and DSD 2.8224MHz and 5.6448MHz - so in hindsight I misspoke - exaSound e20 and the AURALiC VEGA are extremely close in real world performance figures. If you are after an audio processor with more inputs go VEGA - if you are after a DAC with a headphone socket then the e20 is also an excellent choice.

[Big Red Machine]

I just picked up the Lynx Hilo, which with the latest firmware, is promising DSD playback. I've only it had it for a week and have only enjoyed red book and high res. material. So far, it's a fantastic sounding DAC that should scale well in the future.

What chipset is in this dac?  I cannot deduce from their website docs.

[wisnon]

The exaSound e20 and the AURALiC VEGA are extremely close in performance - just look at a comparison of more of of the stated specs.

I really don't think you can just look at the master clock jitter and not compare the rest of the performance figures.

e20 Upsampling  Not stated             VEGA Upsampling 1.5 MHz.
e20 master clock jitter 0.13ps          VEGA master clock jitter 0.082ps
e20 THD 0.0002 %                          VEGA THD  0.0003%
e20 Signal/Noise 128dB                   VEGA Signal/Noise 126dB
e20 IM distortion 0.0000079%          VEGA  Not stated
e20 Channel separation 130dB          VEGA  Not stated
e20 Dynamic range Not stated           VEGA  130dB
e20 Inputs 1xcoax,1xtoslink,1xUSB   VEGA  Inputs 2xcoax,1xAES,1xtoslink,1xUSB
e20 Outputs XLR, RCA, headphone    VEGA  Outputs XLR, RCA

I have no doubt that the VEGA IM distortion & VEGA Channel Separation will be close to those of the e20 - but if you look at the THD and Signal/Noise which are equally as important as the master clock jitter then the e20 is "superior".

While exaSound may not have the pedigree of AURALiC the e20 is clearly a well engineered product (as is the VEGA) - and in some aspects the e20 is "superior"  just as in some aspects the VEGA is "superior". The VEGA was designed as an audio processor - hence more inputs and no headphone socket and costs more - while the e20 is a DAC with less inputs and costs less.

I don't know whether the e20 has a FEMTO clock (now a commonplace bit of silicon) - but one has clock jitter 130 fs versus 82 fs - both very small numbers - and both very good figures. It would be interesting to know the e20's upsampling rate so as to compare that with the VEGA.

In the context we are talking about though with these vanishingly small numbers - in the real world the end result any noise/distortion will be so inaudible that a comparison between the VEGA and the e20 should really be a tie.

Both devices support the same capabilities PCM 384K/32 bit and DSD 2.8224MHz and 5.6448MHz - so in hindsight I misspoke - exaSound e20 and the AURALiC VEGA are extremely close in real world performance figures. If you are after an audio processor with more inputs go VEGA - if you are after a DAC with a headphone socket then the e20 is also an excellent choice.

OK, I can live with that, but the Femto clock would be the decider for me. The other specs have a lower correlation with sound quality, IMHO.

[weff]

Post Correction
I went to the actual AURALiC website to look at their gear and checked the VEGA Specs and found that the actual quoted VEGA Signal/Noise is 118dB and not 126dB as is on the Wizard blog (and which I copied here):
...
e20 Signal/Noise 128dB                   VEGA Signal/Noise 118dB
...
So my apologies for providing wrong information - I should have checked earlier to be certain.

It may not change the overall picture that much - but there is a considerable difference between the two units in that aspect and for me at least that is something I take as important.

OK, I can live with that, but the Femto clock would be the decider for me. The other specs have a lower correlation with sound quality, IMHO.

With respect to the master clock jitter - I wonder how low a jitter the human brain can distinguish? - I  have read that some people can distinguish very minute differences in sound ...but does it extend to that low a value ? It would be interesting to find out.

On a related note I emailed Benchmark Media about their new DAC2 HGC DSD DAC as their details on supported DSD capability is not on their website - nor in the user manual. They are apparently in the process of updating both - but the answer was that their DAC can only support DSD64 and not DSD128.

So the short list now of DSD DAC's that support DSD128 is (and please correct me if I'm there are others) is :

AURALiC VEGA,
emmLabs DAC2X,
exaSound e20,
Meitner MA-1, MA-2,
Mytek 192K DSD DAC (DSD128 Windows USB only)
Playback Designs MPD-3, MPD-5

There is no doubting that the higher end gear like the MA-1, MPD-3 and DAC2X are superb - yet I'm finding that some of the more recent entrants like the Mytek, exaSound and the AURALiC  technically meet and perhaps in many aspects challenge the earlier units - but I'd also scarcely declare them better just on that as more experienced ears than mine that have actually heard them side by side have been sure that the MA-1 and similar are still unsurpassed.

Unless there are other DSD128 DAC's out there - if I want a DAC that also supports 384K/32 bit -  I've to choose from this list which leaves only the AURALiC VEGA and exaSound e20 as contenders ( as no other support  PCM 32bit 384k ) - and as by elimination since I need a DAC (with headphone socket) and not so much an audio processor - the next step is to somehow listen to the e20 and compare with the Mytek and see which one I prefer (up to 192K material) so I can validate the "on paper" test with real world listening.

Before committing to even just trialling the e20 I need to see if I can find out any further technical details from exaSound as to how internally the e20 operates such as what is the internal sampling rate?, do they use a Femto master clock in their design currently and possibly can they perhaps have a Femto master clock with lower jitter as an enhancement ?.  I'd like to see some picture of the internals of the e20 too - for curiosity sake.

[wisnon]

You forgot:

Converter types
Sonore/exD
DAC
Digital to analog conversion
 up to 192
DSD64, DSD128
Cost? $1295!
 
=================

Dont sweat the Femto clocking too much (the e20 does not have it by definition, as clock jitter is in the pico range). Here is what a very informed aqcquaintance told me in conversation:


The Femto-clocks may be a little pointless, as the clock signal afterwards passes through IC's that add tens of ps Jitter unavoidably and I possibly see the future more with Android than iOs, but the principle remains.

----------------------------------------------------------------------


Maybe new pathways will be engineered for the Femto clock signals?

-------------------------------------------------------

Strictly speaking in electrical terms, if I remember correctly, Ed Meitner showed that 5mV ground or power supply modulation on a single gate added 10pS of jitter at 8 * Oversampled CD.

In modern SMD IC's the lead-frames and bond wires (basically the bits that connect the chip to the PCB) cause several 10's of millivolt of ground and/or supply line modulation.

There are 1,000's to 10,000's of gates in each IC's.

So even single number pico second jitter on the audio output is essentially impossible, as long as we use the current kind of structures. So, picoclock's, femtoclock's, they do not do any harm, but their levels of phasenoise are so low that other sources of jitter take over.

It sure makes good ad-copy, who knows, the (unnamed DAC) is due for a refresh, maybe we include a femto-clock, even though we know the output jitter will be in the 10's of picoseconds.

Actually, just for fun, the (sub-$1000 unnamed DAC) has jitter so low, I cannot measure it, it is lower than the DAC's noisefloor. The clock driving this DAC has probably around 10 - 30pS...

A Femtoclock would not be able to make any improvement, nor would be a 1ps Clock...

---------------------------------------------------------

Understood. Its more of a do no harm thing.

[Audioclyde]

Any new word on the 'potential' tubed DSD capable dac mentioned as a possibility above?  Ted's assessment of the Meitner has me seriously thinking about moving to a DSD capable dac from my AMR dp-777......but I really like tubes    !

Thanks in advance for any info.

Randy

[weff]

Dont sweat the Femto clocking too much (the e20 does not have it by definition, as clock jitter is in the pico range). Here is what a very informed aqcquaintance told me in conversation:

The Femto-clocks may be a little pointless, as the clock signal afterwards passes through IC's that add tens of ps Jitter unavoidably and I possibly see the future more with Android than iOs, but the principle remains.
...
Actually, just for fun, the (sub-$1000 unnamed DAC) has jitter so low, I cannot measure it, it is lower than the DAC's noisefloor. The clock driving this DAC has probably around 10 - 30pS...

A Femtoclock would not be able to make any improvement, nor would be a 1ps Clock...

There's more to a DAC than just the master clock (agreed) - but it depends on the DAC architecture how much influence the master clock jitter contributes to the end result jitter after taking all the factors into account. It's bit obscure discussing the phase noise down to the smd gate level - it's easier to understand if we keep to at least a chip level - for it is as that level that any DAC designer has the ability to influence the overall result. They may be stuck with some of the factors (like the individual chip accuracy) but it is as you say the rest of the DAC infrastructure that affects the result.

In the case of the e20 one of those design choices was to use asynchronous USB - and while its master clock jitter (0.13ps or 130fs) is not quite as low as a so-called femto clock (0.082ps or 82fs) - it can apparently also substitute a femto clock chip in place of their existing master clock chip (the silicon form factor is identical) - but the impact of the overall DAC jitter is yet to be measured. (I queried exaSound as to whether the e20 had or could have a femto master clock and they themselves are in the process of testing that as the silicon femto clocks were not available to purchase when the e20 was being designed.  However as wisnon has indicated (as in the case of the unnamed DAC) the master clock is but one factor and  a variety of factors influence the end result - the following is information provided by one of the e20's designers which I think illustrates the real world factors quite well:

The point of using asynchronous USB is to decouple with a FIFO buffer the DAC from the computer.  The FIFO buffer is inside the e20, and data is retrieved from the buffer and supplied to the ESS ES 9018 DAC chip in a separate process that is absolutely independent from the computer and the USB transport.

The factors that influence timing precision for the e20 DAC are:
•   The precision of the master clock – Jitter rating, ppm rating, temperature stability etc
•   The power supplies for the DAC and the clocks
•   The topology of the PCB
•   Noise levels within the DAC enclosure (there is no power transformer inside)
•   The precision of the DAC chip

The factors that e20 is immune against are :
•   Operating system timing inaccuracy caused by non-real-time processing of tasks
•   CPU load – to the point where the USB stream is interrupted for longer than the amount of data in the buffer.
•   Player software jitter
•   USB interruptions – same as CPU load
•   Computer noise on the USB output – if the USB is operational and capable of delivering data
•   Quality of USB cable
 
End of provided information (edited for relevance) .)

As an electrical engineer by profession I am a great believer in actual measurements. So DAC's like the Benchmark Media DAC2 HGC and the exaSound e20 that are less about marketing copy and actually backup their listed specifications with real world performance measurements are going to find favour with me before even brand name DAC's that list capabilities and no actual performance results. I want to be able to compare tangible measurements not subjective (essentially meaningless) audiophile adverbials.

[ted_b]

Weff,
Welcome to AC.  I appreciate your engineering perspective, but you may not get great feedback on a thread like this if you call audiophile listening feedback "meaningless".   

I find that the recipe for great sound can often include a source or piece of equipment that balances or synergizes with the rest of the system.  Sometimes that product is not the best at publicizing its test bench performances.  When you find something that tests well AND sounds great you usually have real long-term success.  Conversely, I have heard plenty of supposedly well-engineered products that sound lifeless and amusical, regardless of what system they are introduced into.

[jcotner]

OK I fit into the engineer category (electrical,firmware,FPGA) and I certainly appreciate the
weight that an engineer would likely give a spec sheet.

But I also have been doing recording work as far back as the late 70's and to me how it
sounds has got to be just as important.

As an example, I have done some power supply work, and I'm not really a power supply
guy. So I can do this great design on paper and then a true power supply guy will
just trounce me in the implementation.
Same thing with DACs. A seasoned designer knows how to spend the right amount of
effort to control board noise, clock jitter, etc. and come up with a great DAC for the
price point.

But what really matters to me, and likely many others, is how you feel after you listen
to a DAC. It's kind of like a wife or child, to you they are the finest in the world, but
maybe to others that's not the case. It's contextual and perceptive.
By all means use the specs to get you in the ballpark but I would never decide on a
piece of audio gear purely bases on specs and not factor in others subjective opinions
on sound and my own opinions of how the gear sounds in my environment.

[weff]

The problem I have with the "adverbials" is that they are by strangers and as you both have stated sound is so subjective.

What may sound good to one of you could sound flat and lifeless to another - whatever that is supposed to mean - and let's restrict this to DSD DAC's - the function of which is to accurately convert digital to analog sound - the more accurate a conversion the better the DAC. That should correlate with better sound - but I have seen enough on this and similar forums to know other factors are in play as "sound" in part is psychology - so is in part subjective.

I would not argue against that - just to me DAC conversion accuracy is essential - and I want basic performance results of any DAC - clock jitter, frequency response, THD, IMD, Channel separation, Signal-to-Noise ratio etc. - the basic measurements any DAC company should supply.  Placing an expensive price tag against a DAC should not preclude a company from at least providing those essential measurements. Then provide whatever adverbials they want.

[wisnon]

Any new word on the 'potential' tubed DSD capable dac mentioned as a possibility above?  Ted's assessment of the Meitner has me seriously thinking about moving to a DSD capable dac from my AMR dp-777......but I really like tubes    !

Thanks in advance for any info.

Randy

The Lampizator said last week on his FB page that he was 90% complete with his prototype. I will push for updates on my side.

[wisnon]

The problem I have with the "adverbials" is that they are by strangers and as you both have stated sound is so subjective.

What may sound good to one of you could sound flat and lifeless to another - whatever that is supposed to mean - and let's restrict this to DSD DAC's - the function of which is to accurately convert digital to analog sound - the more accurate a conversion the better the DAC. That should correlate with better sound - but I have seen enough on this and similar forums to know other factors are in play as "sound" in part is psychology - so is in part subjective.

I would not argue against that - just to me DAC conversion accuracy is essential - and I want basic performance results of any DAC - clock jitter, frequency response, THD, IMD, Channel separation, Signal-to-Noise ratio etc. - the basic measurements any DAC company should supply.  Placing an expensive price tag against a DAC should not preclude a company from at least providing those essential measurements. Then provide whatever adverbials they want.

Why the rant? Nobody is forcing you to go against your principles, if you are attracted to the E30 then please go check it out and report back. We would all welcome that. More choice is good.

[HT cOz]

This looks like an interesting option for the DIY folks. http://www.rigisystems.net/index.php/usbpalen.html

[weff]

Why the rant? Nobody is forcing you to go against your principles, if you are attracted to the E30 e20 then please go check it out and report back. We would all welcome that. More choice is good.

Sorry ... I guess that was a bit of a rant  - ... it just frustrates me that not all DAC companies provide the basic measurements ...but I'll try and restrain myself in future 

In any event I'm finding it difficult to justify another dac - whether e20 or other as the Mytek 192 DSD DAC I have covers all the basic needs currently and higher bitrate media whether DSD or PCM isn't very common. 

It's the "I want a new toy" syndrome I've got to stop.

This looks like an interesting option for the DIY folks. http://www.rigisystems.net/index.php/usbpalen.html

I think this is the underlying module within both the Mytek 192 DSD DAC and Weiss DAC202 if I'm not mistaken as they both use elements of the Rigisystems drivers as part of their code.

[wisnon]

Weff, You already have a Mytek????

Then you dont need to change anything in a hurry (its a fine DSD and PCM DAC). Only a fundamentally different approach should perk you up, eg a tubed DSD DAC.

[HT cOz]

Here is an idea for a cool project that would cost just a few hundred bucks!

The Hifimediy Dac accepts DSD inputs using the CS4398 chip which has a direct DSD path on the chip.  Here are some photos



Notice the DSD Jumper which allows DSD mode to be turned on


Next an inexpensive DSD USB input like this could be incorporated for a nice starter DSD Dac! http://amanero.com/



Could be interesting! 
PS I already have the DAC   

[Ric Schultz]

Back around 2000 I made a non oversampling DAC using the 18 bit stereo Analog Devices AD1865 chip.  One stereo DAC per channel paralleled and a simple op amp for I-V and then right out.  The thing was amazing!  I went on to Audio Asylum and told everyone they had never heard PCM.....and that using a high rez pcm signal into paralleled 24 bit PCM1704s (using non oversampling, of course) and a simple class A output stage would give us digital sound way beyond what we thought. 

Well, no one every seemed to want to go that way.....However, we now have the Totaldac D1.  This French DAC is not only non oversampling but uses a completely discrete 24 bit R to R DAC using 100 nude .01% Vishay resistors ($13.00 each).  The press on it so far is that it might beat anything.  Certainly Srajan at 6 moons thought it was way beyond the $7000 Meitner MA-1 or anything else he has heard.

So, IF this thing does PCM better than anything (yet to be determined, but obviously top notch)......how would it do decoding DSD downsampled to 24/192 versus playing the DSD file directly through the $15,500 Meitner DAC2X?  Could it be close?  Could the Totaldac D1 be better?  We can only guess at this point.  No doubt the "pure DSD" fanboys will say "no way, Jose".  But we won't know till someone does a clear A/B.  I think the Totaldac guy will give you a trial run....so one of you Meitner DAC2X owners should order one from France and do an A/B for us all....he he.....why not?

Interesting times.....digital just keeps getting better and better.

http://www.6moons.com/audioreviews/totaldac3/1.html

[wisnon]

Hi Ric,

I recently got a Lampi gen 4 L4 tube Dac. It too is R2R multibit with no oversampling doing up to 24/192. I have not had the chance to run it it yet or compare to the older Lampi I had which was DS 32/384 specs. All pro reviews on the Lampi have been done on the older Gen 3, none so far on the Gen 4.

I am not sure that it will beat pure DSD properly implemented, but will soon find out as a tubed DSD DAC will soon be born!

[ss44]

I have recently started "acquiring" SACD ISO's and ripping them onto DVD-R's. I have a pretty good system that is extremely revealing. I have found very bid differences between players sound on SACD's!

I have gone from entry Sony, to DENON DBP, to Primare BD32. The Primare completely blows away everything I have heard. But, I do not need the Multichannel or Video section...

That is what leads me to this topic.

I know everyone here is discussing DAC's, but is there not a DSD ISO streamer? Wouldn't this be the most efficient method. Something like a DSD version of the PS Audio Perfect Wave/Lens or Bryston Digital Player...

Does anything like this exist yet?

SS

[ted_b]

I have recently started "acquiring" SACD ISO's and ripping them onto DVD-R's. I have a pretty good system that is extremely revealing. I have found very bid differences between players sound on SACD's!

I have gone from entry Sony, to DENON DBP, to Primare BD32. The Primare completely blows away everything I have heard. But, I do not need the Multichannel or Video section...

That is what leads me to this topic.

I know everyone here is discussing DAC's, but is there not a DSD ISO streamer? Wouldn't this be the most efficient method. Something like a DSD version of the PS Audio Perfect Wave/Lens or Bryston Digital Player...

Does anything like this exist yet?

SS

There are many players (J River, Foobar, Audirvana Plus) that will play the ISO's directly.  by the way, the Bryston BDA-1 is NOT a streamer, it's a Linux music server.  The only thing it may stream is streaming radio, but not sure it does that.