psc704 phillips seismic edge sound card doesn't work

[H.S.]

Running Ubuntu Breezy, lspci shows the sound card is detected but the
sound doesn't work.

The sound card is PSC704 Phillips Seismic Edge and is shown as "
Multimedia audio controller: VLSI Technology Inc QSound ThunderBird PCI
Audio (rev 19)". The various modules loaded are:
~$ lsmod | grep 's.*nd'
snd_mpu401              6344  0
snd_mpu401_uart         6784  1 snd_mpu401
snd_rawmidi            22816  1 snd_mpu401_uart
snd_seq_device          8204  1 snd_rawmidi
snd                    48644  4
snd_mpu401,snd_mpu401_uart,snd_rawmidi,snd_seq_device
soundcore               9184  1 snd

The sound works perfectly if I boot into Windows :(

Where should I start debugging this problem?

Thanks,
->HS
PS: lspci gives:
~$ lspci
0000:00:00.0 Host bridge: VIA Technologies, Inc. VT8753 [P4X266 AGP]
(rev 01)
0000:00:01.0 PCI bridge: VIA Technologies, Inc. VT8633 [Apollo Pro266 AGP]
0000:00:09.0 USB Controller: NEC Corporation USB (rev 43)
0000:00:09.1 USB Controller: NEC Corporation USB (rev 43)
0000:00:09.2 USB Controller: NEC Corporation USB 2.0 (rev 04)
0000:00:0b.0 Multimedia audio controller: VLSI Technology Inc QSound
ThunderBird PCI Audio (rev 19)
0000:00:0b.1 Input device controller: VLSI Technology Inc QSound
ThunderBird PCI Audio Gameport (rev 19)
0000:00:0b.2 Serial controller: VLSI Technology Inc QSound ThunderBird
PCI Audio Support Registers (rev 19)
0000:00:11.0 ISA bridge: VIA Technologies, Inc. VT8233 PCI to ISA Bridge
0000:00:11.1 IDE interface: VIA Technologies, Inc.
VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
0000:00:11.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB
1.1 Controller (rev 1b)
0000:00:11.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB
1.1 Controller (rev 1b)
0000:00:11.4 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB
1.1 Controller (rev 1b)
0000:00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102
[Rhine-II] (rev 70)
0000:01:00.0 VGA compatible controller: nVidia Corporation NV15DDR
[GeForce2 Ti] (rev a4)