On Tue, 13 Oct 2009 09:02:00 +0100, Jim Lesurf
wrote:

Has anyone reading this tried, say, the 'Firestone' USB dac that has an
optical output?

I have an Edirol UA-25, which works under Ubuntu without any problems.
This has been superceded by the 'new and improved' UA-25EX. See, for
example.:
http://www.dv247.com/computer-hardwa...terface--56571

The only problem I have had with the UA-25 was a earth loop when using
the unbalanced analogue output. (The EX model apparently has a ground
lift to help overcome this.)

The analogue output and input seems to have very few undesirable
artifacts from the simple testing I have done. It is switchable
between 44.1, 48 and 96 ksps.

There are a number of similar products from other manufacturers, also
targeted at the pro and semi-pro recording market.

--
Chris Isbell
Southampton, UK