USB to SPDIF Reclocking Adapter?

Jitter is the variation in arrival time of data. In non-packet based digital systems, there is a similar phenomenon known as 'ragged edge triggers'. In a 16 bit system, all bits have to fire (trigger) within a very short window. Chips are rated in part for speed based largely on how narrow that window is. How long it takes that bit to rise from nominal 0 to nominal 1 is the rise time. Chips with large variations in trigger and rise time are considered 'ragged' and only suitable for slow and undemanding applications. Not surprisingly, cheap chips tend towards 'ragged'. G

 

The Valab is not know for having the best USB input. I'd imagine that their USB>spdif would be the same...

As a side note, I have had a good time recently with a Valab USB-to-S/PDIF converter that sells for about $60 on eBay. Using it, I discovered that a good USB cable makes a worthwhile difference.

The mapleshade is a modified hiFace async usb>spdif adapter. Either it, the hiFace or the Empirical devices would be nice additions to using you ARC via computer. You really cannot go too wrong. Buy one, if you do not like it you are only going to loose $30 or so if you resell it (hiface that is).

Many of the current DACs have pretty good implementation of USB/SPDIF, while some do not. Empirical's Off-Ramp and Pace Car do a fine job there. I was pleasantly surprised to find the PS Audio DLIII (a very modestly priced DAC that does a good job overall) did not give up anything switching from USB to Coax to Toslink. Usually there is a wide divergence of performance there. That DAC is available with various upgrades from Cullen Circuits that supposedly improve on the already good stock unit (I only have direct experience with the stock unit, which is very good for the modest price). Audio GD is getting a whole lot of good real-world reviews from their line of DACs. Wyred 4 Sound's DAC as well. No experience with them - just passing on what I've read FWIW.

I don't think jitter is necessarily the key limitation in PC audio though. It is one issue for sure, but also important is the analog output stage of the DAC and power supply. I'm a huge fan of my Modwright Transporter, which even in wireless will easily best the DLIII's output in direct comparison. Eastern Electric has a new USB DAC that I'd be curious to hear about, which uses the Sabre chip. Unfortunately it incorporates a volume control which cannot be disabled short of modifying the design. If you are happy with your current external DAC (which one?) and are just looking to improve the USB>SPDIF performance I'd look to Empirical's products.