[Voyage-linux] More on the Ayre QB-9

[Nick L.]

On Thu, May 5, 2011 at 9:07 PM, jegunn <jeg at astro.princeton.edu> wrote:
>...
> USB1 mode does not work with any recent Linux kernel or any distro I have
> tried; the dmesg error is the one I sent last time, and the one others have
> gotten, about inability of Alsa to read the frequency at ep 01x. The display
> reads 96 (kHz) and the device is dead. With pre-2.6.32 kernels the situation
> is even worse, but the device does not work.
>
> USB2.0 mode appears to work perfectly with a recent snapshot of Voyage,
> kernel (2.6.38, Alsa 1.0.24, compiled for 2.6.38) no matter what order one
> plugs or powers the devices. This is only for two machines, but quite
> different architectures: an old VIA C7 mini-itx and a brand-new
> Zotac AMD Turion Neo M880G. Some of my inconsistent results in my
> last post were due to my being stupid.

>
> Voyage-MPD 0.7.0 works most of the time with the DAC in USB2.0 mode,
> but not always. Again, if the DAC is plugged in to the running computer
> and itself is powered, or if the computer is booted while the DAC
> is powered and connected, it is OK, but powering up the computer first
> and then the DAC does NOT work; it does with the new snapshot.
>
> Anyway, it would appear that the newest version works perfectly in USB2
> but nothing works in USB1 mode. However, all USB ports these days
> are USB2 (or 3--haven't tried those yet, but I have 2 on the AMD
> box) and the DAC plays redbook CD files as well as high-res files
> perfectly in USB2 mode, so for me, at least, the case is closed.

Just to clarify, USB Audio Class 1 and USB Audio Clsss 2 have nothing
to do with whether a USB port is 1.0 or 2.0. The former is the class
for USB audio, with USB Audio Class 1 (UAC1) being limited to
24bit/96Khz. USB Audio Class 2 (UAC2) lets one play files of higher
resolution than 24bit/96Khz. Yes, you should use a USB 2.0 High Speed
port for UAC2 so you can play 24/192 files.

So, UAC1 and UAC2 is different from USB 1.0 (full speed) and USB 2.0
(high speed 480 Mbit/s). The switch on the back of the Ayre lets you
pick between UAC1 and UAC2.

Nick