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Old 7th August 2011, 12:59 PM   #691
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Quote:
Originally Posted by Javin5 View Post
Fine engineering that leaves nothing to be criticized.
I wouldn't put is this way...

1. There is is reason why those external (battery) supplies improve the
performance of that device.
2. I've never seen something powered by USB power performing better
then a well done local supply.
3. Keep in mind the I2S starts on the "messy" side of the fence.
It's IMO more than a good idea to make sure that the messy side
won't be hit by the PC induced mess that hard.
4. The isolator introduces jitter on its own. This leads to an average
(in audiophile terms) performance on the way towards the DAC chip.
5. Propriatary drivers I consider PITA. You 100% rely on that company.
If they'd close down tommorrow you'd be sitting in the dark.
( After 6 years I still receive software "upgrades" for my RME stuff!!!)
6. Beside that, multi OS platform support usually seems to be a
big problem for those companies. Those companies tend to underestimate
initial efforts for multiple OS and revision support and product life
cycle management associated cost. Every platform update can cause driver
instabilities.

I do think that the exa device is a good start into the right direction.
Though from my perspective they are not there yet.
For many people this device will make a nice improvement though. I'm sure about that.

Though I do think certain critism should be allowed. We're at DIY-Audio and not at Computer Audiophile.

I'm looking forward to Rev 2 of that board ( Can we expect a Rev2?) .
I hope they've taken some of the more critical comments made around here into consideration.

I still consider it a pity that I wouldn't be able to use that device on a Linux based system. It would be a great device
for setting up a headless DIY Linux-PC to feed an active system with the filtering done by brutefir.

Cheers

Last edited by soundcheck; 7th August 2011 at 01:08 PM.
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Old 7th August 2011, 02:06 PM   #692
Omholt is offline Omholt  Norway
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Get someone to measure who can give the facts.
There's not much point in sharings thoughts and feelings.
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Old 7th August 2011, 02:13 PM   #693
exa065 is offline exa065  Canada
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Quote:
Originally Posted by soundcheck View Post
I wouldn't put is this way...
We're at DIY-Audio and not at Computer Audiophile.
Cheers
Be more respectful to ComputerAudiophile - it is equally tough to be there. It is mostly the competition doing the criticism, not the ones that have tested exaU2I for themselves. Like here, disbelief is always in theory, not quantified, not backed by measurements or first-hand experience.

hearing is believing
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Old 7th August 2011, 03:15 PM   #694
regal is offline regal  United States
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Quote:
Originally Posted by Omholt View Post
Get someone to measure who can give the facts.
There's not much point in sharings thoughts and feelings.
Soundcheck's suggestions have been pretty well documented and measured elsewhere, it doesn't take rocket scientist to show that a SMPS degrades clock phase. Its funny when folks don't have a Wavecrest they ask for measurements and facts for their specifics. That's just a smoke screen cause the supplier knows few have a Wavecrest or $70k scope, believe me the FTT plots shown don't impress. And postulated calculated summed jitter proposed hold little water in the real world.

That doesn't mean the Exa is anything but good quality but it certaintly isn't the end all to jitter.

The defensiveness and complete close-mindedness toward CI is dissapointing, this thread belongs in the commercial section if that is the attitude.

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Old 7th August 2011, 04:03 PM   #695
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Quote:
Originally Posted by regal View Post
Nice, Have you compared the NOS mode to the apodizing filters? Also are you using external power still for the EXA voltages 5v, 3.3v, 1.8V? Sharing the USB ground with the WM ? What are you using for an output stage?
There was only one configuration of the WM8741 that allowed higher sampling rates, so I haven't tried the different filters.

I'm using the exa in standard configuration. No fancy power supplies. Running shunt regulators for the WM8741 though. No output stage. That's the beauty of the Wolfson dac; very low noise, and capable of driving 1 nF 1 kOhm loads. Compared to the First Watt B1 buffer there isn't really any noticable difference.

And all this grounding talk... I'm not into that split isolated grounds stuff. I'd really prefer everything on one board, with shared ground plane for Agnd and Dgnd and Vgnd. Of course, isolating everything from the computer is beneficial. It seems to me that exa have taken the necessary measures to prevent noise from the computer. It's completely noise free compared to the other USB devices I've tried.

A separate psu for the clock would surely be better... in theory. But I believe we're talking minor differences. There's always a question of price vs. performance. Increasing perfomance at this level of quality is usually not worth the cost, IMHO. Of course, there's always one person who wants to spend the extra hundreds of dollars making a cost-no-object setup. But for a commercial product you have to stop at some point. In my eyes exa has hit the right spot. It's a true high end product at an affordable price.
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Old 8th August 2011, 03:29 AM   #696
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Quote:
Originally Posted by exa065 View Post
Be more respectful to ComputerAudiophile - it is equally tough to be there. It is mostly the competition doing the criticism, not the ones that have tested exaU2I for themselves. Like here, disbelief is always in theory, not quantified, not backed by measurements or first-hand experience.

hearing is believing
If the competition is nit picking at your product and you haven't over exaggerated its claims then that means you are on the right track

regards
Trev
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Old 8th August 2011, 03:47 AM   #697
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Quote:
Originally Posted by soundcheck View Post

I'm looking forward to Rev 2 of that board ( Can we expect a Rev2?) .
I hope they've taken some of the more critical comments made around here into consideration.

I still consider it a pity that I wouldn't be able to use that device on a Linux based system. It would be a great device
for setting up a headless DIY Linux-PC to feed an active system with the filtering done by brutefir.

Cheers
I wouldn't be doing a Rev 2 just because you wanted something changed. That is the quickest way to go broke in a start up business The board is obviously of use to others the way it is. It just means that it is not suitable for your needs but doesn't mean that it is of no use to others

regards
Trev
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Old 8th August 2011, 08:11 AM   #698
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As I wrote. Many people will be happy with the device. Enjoy.

I also wrote that I consider that device well done from what I read. I just wouldn't buy it at this stage.


I do have a problem with people who think and communicate it couldn't
be done better.

The first thing Raytech did, was hooking up better PS
with great results. There is nothing to argue about.
Many people around here are also using battery powered devices
since quite some time. We all know what to expect.
It makes sense to everybody who played around with this stuff for a while.
Perhaps some of you know that Jkeny did very similar PS mods on the well regarded buspowered M2Tech devices and even sells his mods.
(I applied those mods a long time ago to my USB DACs and TP Buffalos)

The jitter issues around the isolator we've been discussing earlier. There's nothing to argue about or to measure. It's in the specs. EXA can't get around that.


Many people are happy with Twisted Pear stuff, even though I always considered it average. (BTW: Can't remember if TP has ever started marketing threads like EXA btw - I doubt it.)
You can easily follow the progress TP made from revision to revision.
Well done engineering. Of course. But it's nothing that can't be improved.
They listen to the crowd and do something about it. They won't start arguing about it. Pretty successful strategy so far.

I'm sure there'll be a Rev 2 of the EXA unit sooner or later. Of course they can't talk about it over here. This is a marketing thread about the Rev1 board.

I'd also expect that one day EXA comes up with a 100% commercial USB DAC based on Sabre. There are many people who started up at DIY-Audio
and turned into full open-market commercial operations.

---

Let's talk about respect dear exa065:

You run a commercial marketing thread on a 100% commercial product
at a commercial free forum. It's you who don't respect the rules and members of this forum.
Get this thread moved over where it belongs.
The admins obviously seem to be on holidays and let you run your show.

You even admit how difficult it is for you to get your feets on the ground
in a rather "commercial" forum such as Computer Audiophile where all the manufacturers chime in into the discussions. ( No - you won't see that over here)
DIY-Audio obviously makes your live easier to run your show.
Well done.


Cheer
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Old 8th August 2011, 03:11 PM   #699
exa065 is offline exa065  Canada
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Quote:
Originally Posted by soundcheck View Post
As I wrote. Many people will be happy with the device. Enjoy.
Cheer
Soundcheck,
There is more to our disagreement than the commercial / DIY aspect and the Jitter / USB power debates. exaU2I is an alternative device and it challenges the conventional thinking and practices. It is about doing more with less. It is about making a statement - good sound can be achieved with good engineering and without doing extreme things. We demonstrate that it is not just this or that parameter taken to the extreme - it's the integrity of the concept and the engineering effort.

We haven't changed the device not because of lack of respect to the DIY community or because we are in denial. We want the alternative message to propagate. It is not the Teflon board or the fancy capacitors that make the big difference. Sure, you can add them and squeeze every last bit of juice. This is not what makes us excited.

exaU2I is on diyAudio because this is the best place to meet open-minded risk-taking audiophiles. Pick a device that you like. Our experiment is about minimalistic approach and integrity.
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Old 8th August 2011, 06:45 PM   #700
Takaji is offline Takaji  Canada
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Quote:
Originally Posted by soundcheck View Post
As I wrote. Many people will be happy with the device. Enjoy.
I don't see exa065 as trying to aggressively promote their product as the only solution, so what's the problem? The thread started with exa telling us of an upcoming board... accepting criticisms and answering questions promptly. I don't see any overt "buy buy buy"-attitude from their part.

I think exa would agree that anybody is welcome to do their own tests on the exaU2I board and post the results. And I'm sure that all of our concerns are being noted and being considered for the next revision - which shouldn't come immediately, but should definitely come at some time. The exaU2I is already a spectacular piece of equipment that I am excited to try.

Any mods to the hardware are certainly fine to be shared in this thread, I think... exa has even gone so far as to post the battery mod on their website. They are leaving this board open to experimentation and mods.

But then again, some people will never be satisfied, which is understandable, since you can't make something that 100% of people will enjoy.

Maybe someone can help me understand... what difference does it make whether the thread is under DACs or Commercial? TPA's BIII DAC is under Commercial, so I suppose this one should be too..?
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