[linux-audio-user] Edirol UA-25: Any issues?

Pete Leigh pete.leigh at gmail.com
Thu Nov 17 20:25:36 EST 2005


Hello there..

I'm also interested in this device, and some of the reading I've
done will allow me to answer a couple of your questions.. hopefully
the answers might even not be completely wrong :)

> * I read it is bus powered; but I wonder how can it get 48V phantom
> power from the USB bus?!?

I think the phantom power is supplied at a few milliamps, hence not
much power is needed, just a resistor with the right value, since
V=IR, right? (Correction welcomed from actual EE's :)

> * I read somewhere on the web that there was a little hiss on the
> inputs. Can anyone confirm this, and is it OK or too much?

If you read what I did,
( http://music.columbia.edu/pipermail/linux-audio-user/2005-October/027689.html
)
the hiss was from the components inside the unit, not on the input
channels, I think. Comments about the sound quality I've seen have
been positive.

> * Can I use both outputs at the same time to connect all of them to
> different destinations? Do they appear in ALSA/JACK as 2 or 4 different
> ports?

I'm pretty sure you can only run two output channels (or 1 stereo)
at one time, that is I think you'll get only 2 ports in alsa.

I'm not sure whether the different physical output ports on the device
run  simultaneously, but it would seem strange not to. Don't know
about the digital output, though.

> * Last but not least: Does it run at full duplex (2 ins and outs at the
> same time), and what latency can it provide (the lower the better :) ?

>From the info at edirol.net, it will run in full duplex at up to 48KHz, and
"half duplex", either in or out, at 96KHz.

I gather from the downloadable manual that it will only do 16/44.1
with advanced mode switched to off, and only 24bits with advanced
mode on, at least under windows. I'd be interested to know whether
16/48 could be achieved under Linux, despite this (ie if it's a limitation
of the windows drivers).

A user on this list reported latencies around 5ms a few months ago

http://lalists.stanford.edu/lau/2005/07/1233.html

If ua-25 owners that happen to read this could make an entry
at http://www.qbik.ch/usb/devices/ it would be very helpful!

Now, not to hijack your thread, or anything, ... but ... ;)

I've also been looking at the UR-80 - which has similar features to
the UA-25, minus the limiters and the loopback feature, but with
a 43-control midi controller interface added (they are very cheap
at one online store I've looked at, about the same price as the UA-25,
which seems a good deal).

Clemens Ladisch was helping someone get this going, but (from
looking at the archives) the attempt fizzled out when a request to
provide lsusb -v output at the different settings went unanswered
(sort of). I'd guess it could be made to work.  Apparently there is
an alsa patch especially for it, but I don't know if that means the
controller stuff will work, and how much of it.

Any info on this device under Linux would be very interesting to me.

Also any info on ua-25 alternatives, as in my (unanswered (sob) ) post
of a few days ago..

Cheers,

- Pete.



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