exaU2I - Multi-Channel Asynchronous USB to I2S Interface

[Nikola Krivorov]

DAC based on the ESS9018 sounds fine to me Is it something you have heard about or just an idea to use what they already know about the interaction between the Buffalo and the ExaU2I? If it will be as good as the ExaU2I I will surely try it though I am working on my acko based DAC with Owen's D1 version with highly sophisticated PSU arrangement. I was planning to implant the Buffalo II I had on the Hiface Evo so it comes as a natural idea to do that but I guess designing the topology from scratch would be even better. But then comes the thing with the I/V which can kill or sky rocket any DAC, a whole Universe by itself...

The Exa guys obviosuly know what they are doing, if only the OSX drivers were available... There is no device that comes perfect and you are right the exa065 sounds a little too confident in his design decisions, as if there are no other routes but the ExaU2I sure sounds and behaves quite mature, you can never be certain how many iterations it had before and for me the design decisions are quite obvious for people who can read that kind of stuff. When I spoke with my friends who are good in that field they sure had other ideas and criticism(clocks for example are not fancy) but then they say that there are things that are not easily shared as there are always people stealing ideas and the ExaU2I already exceeds their expectations. You don't get the Hiface guys to answer questions here or any other manufacturer, everybody likes to let you think they thought of something that no one else had an idea how to implement. For me the biggest compliment is that RayCtech likes it and he sure knows more in electronics than most of the people I know, which is quite a compliment. Not affiliated to Exa team in any way apart from email exchange, just mighty impressed by RayCtech's stuff.

[Coris]

I can see that soundcheck just try to remove exa065 from every place (including this thread/forum because he just do not like him and/or his work. This kind of criticism is out of point mr. soundcheck! Have you done something better? Have you experment with this board and found it a better way, and came here with facts? Or is the problem that exa065 do not listen to you and make that changes you want/like for your own? Do not like, do not use! Very simple... Make your own and better, and that all. What should be this forum without these people who put the ideas in practice, produce something not only for themselves, but for others too.... For this work, the time they use and the component in this board, one have to pay for. So, what is your problem in all this? The show is not of exa065, but I can clearly see that you try to produce a one man show...
So? The show must go on? I think NOT in this way...

[pinnocchio]

Originally Posted by Coris

I can see that soundcheck just try to remove exa065 from every place (including this thread/forum because he just do not like him and/or his work. This kind of criticism is out of point mr. soundcheck! Have you done something better? Have you experment with this board and found it a better way, and came here with facts? Or is the problem that exa065 do not listen to you and make that changes you want/like for your own? Do not like, do not use! Very simple... Make your own and better, and that all. What should be this forum without these people who put the ideas in practice, produce something not only for themselves, but for others too.... For this work, the time they use and the component in this board, one have to pay for. So, what is your problem in all this? The show is not of exa065, but I can clearly see that you try to produce a one man show...
So? The show must go on? I think NOT in this way...

I second that!

BTW, let's just stop the bitching altogether... This is making the thread look like a bunch of school girls battling it out!

Let's bring in the ideas which in turn will create innovation, not put sticks in those turning wheels... For Christ sake, you don't like the product then don't buy it... It's that simple!

I don't own one but it sure looks like a promising product, enough that I'm interested in buying one.

SoundCheck, you say that TP does average work... Do you have a DAC project that sounds better than the BII/BIII? Would you care sharing with us? Dual mono BII that I own sounds fantastic... Again, I'm all ears!

Thanks

[rsdio]

Originally Posted by regal

Your DAC has Vdigital and Vanalog supplies, it aslo has an analog ground and a digital ground. The isolation if needed should be here between the DAC digital ground (which should be shared with the Exa) and the DAC analog ground.

That's a reasonable suggestion, but if you examine the data sheets for several DAC chips, you'll find that many of them recommend that you NOT isolate DAC digital ground from DAC analog ground. It's counterintuitive, especially since many DAC chips have separate pins for analog and digital ground. The point is that inside the DAC chip there are both digital and analog circuits, so if the digital side is noisy then the analog side will be noisier, even if they're separated outside the chip. It seems that the best practice is to provide as clean a digital supply as possible to the DAC chip so that there is less noise crosstalk into the analog section. Then again, there are many DAC chip designs out there, and the data sheets do not all recommend the same schematic and board layouts.

Think about it, you are saying that the computer ground is too dirty for the DAC chip digital side, yet just fine for the delicate clock for asynchrous USB. A ground is a reference, if all digital is sharing the same ground it becomes a mute point.

I see your point, but the USB clock is not delicate. The entire USB specification was designed such that cheap electronics would work reliably. I suppose you're talking about the I2S Word Clock and not the actual USB clock?

[Coris]

[QUOTE=rsdio;2665591]That's a reasonable suggestion, but if you examine the data sheets for several DAC chips, you'll find that many of them recommend that you NOT isolate DAC digital ground from DAC analog ground.


Can someone please come here with some facts about these subject of isolate or not digital/analog GND? I mean somebody who have an Exa board (and want so much to show that isolation of these GND is wrong), just remove the isolators, make the connections, run some tests, take some plots and publish here the result. This can (in my opinion) be the only step forward. Something more than only talk (write)... Of course is not wrong with critic of an concept, but can we please see some small facts in all this?
I personally agree with the concept of isolation GNDs, and I have no problem (yet) to adopt it.
So, could be nice to see some facts in this (another one) respect... The critic for criticism sake I think is only wasting time... Anyway, that is the reason of a forum: discussion...
But blame somebody who make steps forwards, create something in practice, try something in the facts fields, and work quite hard for this, is not just the right thing to be done on this forum...

[rsdio]

Originally Posted by Coris

Can someone please come here with some facts about these subject of isolate or not digital/analog GND? I mean somebody who have an Exa board (and want so much to show that isolation of these GND is wrong), just remove the isolators, make the connections, run some tests, take some plots and publish here the result. This can (in my opinion) be the only step forward. Something more than only talk (write)...

That's a fine suggestion, but there will be no end of 'facts' because each DAC chip is different. I welcome people to test specific chips and report on the actual results; but please, everyone, rest assured that actual test results for one chip will not guarantee the same results with a different DAC chip.

There is no one single answer for all DAC chips on the question of "isolate or not"

[RayCtech]

The exaU2I is still the best sounding device to get audio out of a PC (soon also a Mac) that it is possible to buy at the time beeing!
From my experience it is possible to improve the audio quality by both improving the power supplies and by implementing galvanic isolation of the USB - this is nothing new or strange - it is mainly a cost / price issue.

If you have the "best" PC / Mac, DAC, power amplifier, cables and speakers you can buy I expect only a few will be able to "hear" any audible improvements by tweaking / upgrading the exaU2I.

The weakest link in the chain is the PC / Mac and thus I have built up my own fan less and battery driven systems. The cabinet with heatpipe / heatsink and powersupplies / batteries are 10 times more expensive than a standard cabinet with a standard PSU, and if the cost of the time used to do the building and tweaking are added - figure it yourself...

In my setup I have myself designed and built everything except the PC / Mac and the USB -> I2S units, but those units have been upgraded and tweaked to the maximum Fidelity.

Due to the still missing (expect they will show up soon) Mac OS X drivers I have been using another product than the exaU2I for some months, but it is a product that are not possible to buy.

If I in my setup should have been limited to standard engineering practices and measurements - I would have missed the Audio quality I have been able reveal and I would have been better of by buying some standard finished products and saved a lot of time and money

[AlanElsdon]

Anyone know how to get the EXAU21 Dashboard to recognise exau21 driver?

[exa065]

Originally Posted by AlanElsdon

Anyone know how to get the EXAU21 Dashboard to recognise exau21 driver?

Hi Alan,
In the player control panel you need to select exaU2I ASIO DB. DB stands for Dashboard. The DB version of the ASIO driver is installed by the Dashboard setup.

[AlanElsdon]

Thanks for that - I am now trying to load exau21 onto my cMP2 machine which is running under Windows XP SP2 - the installer will not run - do I need Service Pack 3?

Alan