Does USB->I2S make sense ?

[percy]

Originally posted by peufeu
USB audio standard 2.0 should correct this.

I thought the problem was pre-Vista Windows operating systems and also the unavailbility of hardware (like usb interface chips) that can provide the Asynchronous feature in a 'ready to use' form. I believe the standard always had the capability. Or in other words - what changed in 2.0 that would correct something ?

iirc, there have been successful implementations of Asynchronous feedback in USB in Linux and in usb v1.1 .

[peufeu]

I seem to remember from reading the specs that, while 1.0 allows it, USB Audio 2.0 makes it a lot easier to use asynchronous mode. Maybe that's the reason why...

USB Audio 2.0 should correct this because it specifies asynchronous mode in much more detail, and hopefully driver developers at M$ will implement the complete standard this time... and maybe get it right ? who knows.

[AR2]

Originally posted by peufeu
I seem to remember from reading the specs that, while 1.0 allows it, USB Audio 2.0 makes it a lot easier to use asynchronous mode. Maybe that's the reason why...

USB Audio 2.0 should correct this because it specifies asynchronous mode in much more detail, and hopefully driver developers at M$ will implement the complete standard this time... and maybe get it right ? who knows.

With all that I have been reading here and in other threads, I am of the opinion that it would be useful to majority of people on this board to find some external firewire card that will be suitable for modification. Than use their fire wire protocol and than work and develop something from there. So in the another words, have obvious benefits from firewire that seems to be untouchable part for majority of us and work on the part we can. Just an idea.

[soundcheck]

Originally posted by lucpes
Hi there,

I'm using a M-audio transit to get I2s from a TAS1020A chip (USB) and it sound quite good into a TDA1541A. Much better than an EMU 1212m internal card. Get one of those, follow the datasheets and you get the pinout.

Make sure that the USB card has the proper grounding with the DAC board, other than that, happy listening.

Regards,

Lucian

I got one of these M-Audio Transits.

1. It is USB powered. IMO - NoGo.
2. It is noisy. IMO - NoGo.
3. It is isync. IMO- ??? It depends heavily on your PC setup
4. It delivers 24/96 - OK

I2S I havn't tried yet.

I currently feed my Buffalo DAC with I2S from a PCM2707 receiver ( Old DDDAC).
This sounds better than SPDIF from USB 0404 USB (async USB) to Buffalo.

I havn't managed to get the M-Audio transit working with my Opticis USB cable under Linux.
(I am connecting all my USB PCM 270x based receivers via Opticis)
This way I feed it with clean 5V regulated battery power. I figured out that the galvanical USB isolation plus a clean local USB 5V supply, will improve performance quite heavily. Unfortunately these Opticis devices ( with a downstream PS) are USB 1.1 only.

Anyhow I'll give M-Audio Transit - I2S a try. (I'd appreciate if you could PM me to give directions - picture? of your mod)

Cheers

[BrianDonegan]

USB -> I2S -> ASRC (with good clock) -> DAC. Then the USB source jitter doesn't really matter.

[sangram]

Brian,

Would running a USB->I2S give similar results for (for example) the Buffalo DAC that always reclocks the data stream?

If so, what are the potential benefits of running off USB vs. SPDIF for such a DAC?

[BrianDonegan]

Originally posted by sangram
Brian,

Would running a USB->I2S give similar results for (for example) the Buffalo DAC that always reclocks the data stream?

If so, what are the potential benefits of running off USB vs. SPDIF for such a DAC?

Theoretically, there is no difference between USB->SPDIF and USB->I2S [edit] feeding the ES9008 [/edit]. At least according to Dustin at ESS. Is that what you are asking?

[sangram]

Not exactly my question, I was referring to running the 9008 in SPDIF mode (direct SPDIF input, not I2S).

I was looking for a point of view between USB->I2S (or any other I2S-converted mode) and direct SPDIF, actually.

[planet10]

Originally posted by AR2
to find some external firewire card that will be suitable for modification.

I'm on a budget... this is the one i've been looking at.

http://www.rolandus.com/products/pro...1&ParentId=114 (excuse the b^&%$# flash)

I have the USB one in the same paxkage and it is nice.

dave

[BrianDonegan]

Originally posted by sangram
Not exactly my question, I was referring to running the 9008 in SPDIF mode (direct SPDIF input, not I2S).

I was looking for a point of view between USB->I2S (or any other I2S-converted mode) and direct SPDIF, actually.

Unless there is data actually missing (rare), then the results shoudl be the same.