Request For Layman's Guide: Low Jitter S/PDIF computer output, software independent

[schaqfu]

I have searched the threads with reckless abandon, but there is just too much detail to digest. Can I please prevail upon those rarified few (of whom there are an impressive number on head-fi!!) who have the needed combination of technical prowess and plain-spoken writing, and whatever other special sauce is necessary, to write a layman's guide in response to the following question:

How does one get the highest quality, lowest jitter S/PDIF transmission from a computer to a high quality external DAC (HeadRoom Balanced Desktop w/ integrated "Home" DAC)? I'm spending all this money on the DAC, I want to make sure I'm not limiting it by just plugging it into the USB port directly. It seems like a huge number of people have the same or similar question but run into the same problem I am -- technical detail overload!

Ideal solution will meet the following criteria:

1) Connects via USB
2) Is software player-independent (doesn't matter iTunes/WMP/Foobar/etc.)
3) Does not require configuring USB drivers - simple plug n play
4) Can handle 192/24 output; but 96/24 is sufficient
5) Bit perfect: no resampling or upsampling - let the DAC handle that.

In particular I have seen products from E-Mu, M-Audio, Empirical Audio, etc., but I can't make heads or tails of which ones will reduce jitter the most and be cost-efficient. It would be great if a guru could post several solutions, including high-, medium- and low-cost solutions. I would be in your debt! Thanks!!

 

[lowmagnet]

As far as jitter free playback (assuming windows):

When connecting your device (whatever device) via USB, you can just connect it if your device uses the standard system drivers. Most of them do this without issue.

To get 24/96 plug-and-play, I think there are two DAC that can do this, Benchmark DAC1, and one other whose name escapes me. Someone will pipe up with it.

Don't expect 24/192 from USB without custom drivers.

In order to prevent re-sampling, turn program volume up to max (or 0dB amplification if the app provides it) and disable any plugins that tweak your sound.

Set your device up so it puts out 24 bits (that's fine) and 44.1 kHz if you're playing CD rips.

Make sure the IRQ of your USB port is not shared by something like a network card, because that can cause clicks and pops.

If the above doesn't work, you can run ASIO I suppose, but if it does work, don't bother with this as it shouldn't be necessary.

I think that's it.

 

[schaqfu]

I am looking for a USB-to-S/PDIF transport to stick between the computer and the DAC. I know USB-to-DAC has acceptable quality but I don't want to use the converter implemented in the DAC because it's limited. Sorry I wasn't clear, this is a request for a USB-to-S/PDIF converter transport or, if that just ain't gonna fly for highest quality, a PCI card that will output S/PDIF. In both cases the goal is getting it as jitter-free as possible. Seems like something that incorporates a Superclock4 is the best solution imaginable, but it also sounds like that's going to cost minimum $600.

Thanks!

 

[lowmagnet]

Quote:

Originally Posted by schaqfu /img/forum/go_quote.gif I am looking for a USB-to-S/PDIF transport to stick between the computer and the DAC. I know USB-to-DAC has acceptable quality but I don't want to use the converter implemented in the DAC because it's limited. Sorry I wasn't clear, this is a request for a USB-to-S/PDIF converter transport or, if that just ain't gonna fly for highest quality, a PCI card that will output S/PDIF. In both cases the goal is getting it as jitter-free as possible. Seems like something that incorporates a Superclock4 is the best solution imaginable, but it also sounds like that's going to cost minimum $600. Thanks!

The interface (S/PDIF) has more to do with the jitter than the clock of the driver device. Various people have mentioned countless S/PDIF devices for USB on the forums, so I can't really add anything to that discussion.

If I may ask, what are the USB limits of your DAC? 24/44.1? 24/48?

 

[schaqfu]

Quote:

Originally Posted by lowmagnet /img/forum/go_quote.gif If I may ask, what are the USB limits of your DAC? 24/44.1? 24/48?

Limits are 24/48, which is only half the problem. I'd like to be able to feed 24/96 and 24/192 files directly to my HeadRoom Home DAC upgrade, but I'm also not confident the USB-to-S/PDIF conversion that takes place inside the DAC is high quality. I'd like to find a unit that converts USB packet data into as clean an S/PDIF signal as possible. That would bypass the conversion in my DAC altogether.

I'm just hungering for a little box that takes USB in and puts S/PDIF out, in the most jitter-free manner possible. And I want it to work with iTunes and WMP.

 

[Xakepa]

Quote:

Originally Posted by schaqfu /img/forum/go_quote.gif but I'm also not confident the USB-to-S/PDIF conversion that takes place inside the DAC is high quality

Really?

 

[schaqfu]

Quote:

Originally Posted by Xakepa /img/forum/go_quote.gif Really?

It would be awesome if someone could compare the USB-to-S/PDIF conversion quality inside the HeadRoom Home DAC board compared to that of some other S/PDIF output options direct from computer.

 

[lowmagnet]

Quote:

Originally Posted by schaqfu /img/forum/go_quote.gif It would be awesome if someone could compare the USB-to-S/PDIF conversion quality inside the HeadRoom Home DAC board compared to that of some other S/PDIF output options direct from computer.

My Mac tower puts out a maximum 24/48 to optical. I've read about synchronization issues with 24/96 on optical, so there may be some limit to LEDs there.

 

[regal]

USB has issues with jitter from the 1khz packets. Obviously PCI soundcards are bad because of the terrible PS.

The Squeezebox is your only real option for low jitter out of a computer. Look at their advertised jitter specs, they are impressive.

 

[schaqfu]

I've found what I hope is the solution I was asking for, in the Benchmark DAC1 USB. If you believe the hype, and the really quite well documented technical evidence, here: http://www.head-fi.org/forums/showthread.php?t=225363

It claims to produce 100% jitter-free audio at resolutions up to 96 Khz / 24-bit over a standard USB connection (including USB 1.1!!!) with no special drivers or configuration required, using just about any media player. As far as pure signal processing, THAT is the holy grail of USB audio as far as I'm concerned. Add to this the fact that its DAC processing is rated top-notch, and it's got a quality headphone amp built in, and balanced outputs -- this is one dynamite box on paper. Hopefully when it arrives on my doorstep it will live up to it!

 

[Gatticus]

http://www.positive-feedback.com/Issue22/nugent.htm

 

[schaqfu]

Quote:

Originally Posted by Gatticus /img/forum/go_quote.gif http://www.positive-feedback.com/Issue22/nugent.htm

It's been a jaw-dropping conversation between Steve Nugent, from your link, and Elias Gwinn of Benchmark Media, the makers of the DAC1, on this thread: http://www.head-fi.org/forums/showthread.php?t=225363 I see you've been monitoring too. It has made me completely rethink the viability of USB as a jitter-free medium. I can't see any reason anymore not to run 100% off computer audio, except for those formats like SACD that cannot be ripped to it.