[audioengr]

I am curious how many use only the S/PDIF output and dont use the analog outs on the 0404 USB 2.0 module or the add-in card. This would be to drive an external DAC.

This is an interesting product because it evidently uses a different protocol for USB than most USB converters, with an independent clock. I believe the PCI card also has an independent clock.

If there were enough interest in this, I could buy a 0404 and develop a simple mod for it that would allow it to be used with my new Pace-Car reclocker. Then those that have 0404's could have the option to upgrade their systems to ultra-low jitter by adding the Pace-Car. This is similar to what I currently do with the Squeezebox and Sonos.

Steve N.
Empirical Audio

 

[sejarzo]

Interesting post, Steve.....it begs the following questions:

1. What do you mean by the "add-in card" on the 0404 USB? I'm befuddled by that one.

2. The only way to use the 0404 USB's digital outputs appears to be via the ASIO drivers, according to the web site and my experience. In Foobar 0.8.3, using foo_output_asio(dll).dll (file size 111,104 bytes, modified 31 Dec 2005), I have to go into Preferences>Output>ASIO (dll version) and set "Shift Output Channels" to 2 (rather than zero for using the analog outputs.) I take it you are aware of that?

Side question, if I may......I may have misinterpreted a previous post from you, but I think you had an opinion as to which ASIO component was the best one to use with Foobar 0.8.3. Is the one I noted the one you would choose?

3. From a PM a few weeks back, I know that AKM is not your preferred flavor of DAC

........ would you really advocate buying the 0404 USB simply as a USB>S/PDIF converter? I can see that's a definite need if used with a notebook, but what are the advantages of using the 0404 USB to get an S/PDIF output if one could buy a cheaper 0404 PCI for a desktop?

4. Sorry if I missed this elsewhere, but would you please flesh out the topology of the set up and the advantages of using the PaceCar with an external DAC via a device such as the 0404 USB? I have a problem with an asymmetric listening room and am getting a room-correction digital preamp soon, and I am trying to determine the best way to feed it from my desktop.

A bit more of an explanation of how you feel the total 0404 USB implementation differs might be of value, too, for those of us who are not extreme techies.

Thanks!

 

[audioengr]

Quote:

Originally Posted by sejarzo /img/forum/go_quote.gif Interesting post, Steve.....it begs the following questions: 1. What do you mean by the "add-in card" on the 0404 USB? I'm befuddled by that one.

I was under the impression that there was a PCI card version with no USB 2.0 interface.

Quote:

2. The only way to use the 0404 USB's digital outputs appears to be via the ASIO drivers, according to the web site and my experience. In Foobar 0.8.3, using foo_output_asio(dll).dll (file size 111,104 bytes, modified 31 Dec 2005), I have to go into Preferences>Output>ASIO (dll version) and set "Shift Output Channels" to 2 (rather than zero for using the analog outputs.) I take it you are aware of that? Side question, if I may......I may have misinterpreted a previous post from you, but I think you had an opinion as to which ASIO component was the best one to use with Foobar 0.8.3. Is the one I noted the one you would choose?

I've play with all of them. The ones I like best are:

ASIO SSE2 47a
and
ASIO SSE2 51

The 47a is smoother, but the 51 is more detailed.

Have you tried unmapping the device? This can sound even better when combined with DirectSound2:
http://www.audiocircle.com/circles/i...?topic=40068.0

Quote:

3. From a PM a few weeks back, I know that AKM is not your preferred flavor of DAC ........ would you really advocate buying the 0404 USB simply as a USB>S/PDIF converter? I can see that's a definite need if used with a notebook, but what are the advantages of using the 0404 USB to get an S/PDIF output if one could buy a cheaper 0404 PCI for a desktop?

This is what is unique about the 0404. Because of its special independent clocking scheme, it can be used with the Pace-Car just like a SB3, Sonos or Olive. I would drive a "Master Clock" back to the 0404 from the Pace-Car. Then, the Pace-Car is in sync with the 0404.

There is no way to do this type of sync with an S/PDIF output on a laptop. The only way to sync the Pace-Car is to use it in another mode which requires that I "tune" the Pace-Car to the frequency of the particular laptop. This is all avoided with the 0404.

Quote:

4. Sorry if I missed this elsewhere, but would you please flesh out the topology of the set up and the advantages of using the PaceCar with an external DAC via a device such as the 0404 USB? I have a problem with an asymmetric listening room and am getting a room-correction digital preamp soon, and I am trying to determine the best way to feed it from my desktop.

The primary advantage of the Pace-Car is the it reduces the jitter level to inaudible levels.

Quote:

A bit more of an explanation of how you feel the total 0404 USB implementation differs might be of value, too, for those of us who are not extreme techies. Thanks!

The clock in the 0404 is independent, unlike the clocks in most USB to S/PDIF converters. This means that the clock can be driven from another device, making the 0404 a "slave" device. This is how "word-clock" inputs work on really expensive Transports.

Because of this clock independence (from the Computer clock), one can easily interface the 0404 to the Pace-Car and achieve extremely low levels of jitter into an external DAC. Minimal rework to the 0404. The jitter from the 0404 does not matter either. The Pace-car reclocks it, so the output master clock is independent. To take advantage of this low jitter, the best solution is a DAC with I2S input. However, the next fab of the Pace-Car board will support S/PDIF output, albeit at slightly higher jitter levels.

Steve N.