Audio output for PowerMac G5

[Rick Thomas <rbthomas@pobox.com>]

I have an ancient PowerMac G5 dual-core 2.0GHZ (PowerMac11,2) machine I'd like to use to help Hanno Zulla test his new "Sonic Pi" software on bigendian hardware.

But alsamixer tells me I have no audio cards and no audio devices.

Or, to put it another way:
> rbthomas@bigal:~$ ls -l /proc/asound/
> total 0
> -r--r--r-- 1 root root 0 Mar  5 19:31 cards
> -r--r--r-- 1 root root 0 Mar  5 19:31 devices
> -r--r--r-- 1 root root 0 Mar  5 19:31 modules
> dr-xr-xr-x 2 root root 0 Mar  5 19:31 oss
> dr-xr-xr-x 2 root root 0 Mar  5 19:31 seq
> -r--r--r-- 1 root root 0 Mar  5 19:31 version
> rbthomas@bigal:~$ cat -v /proc/asound/cards 
> --- no soundcards ---
> rbthomas@bigal:~$ cat -v /proc/asound/devices 
> rbthomas@bigal:~$ cat -v /proc/asound/modules 
> rbthomas@bigal:~$ 

Am I just not loading the right kernel modules?  I'm pretty sure I was able to use this machine with iTunes when it was running MacOS-X, so there is audio hardware in there somewhere.

Thanks for any help!
Rick