[Alsa-user] ticking when recording from usb headset

[Julian B. <jcb...@jc...>]

I have a C-Media USB headset, which I plug into my Dell PC running
Scientific Linux 5 (kernel 2.6.18, ALSA 1.0.14rc3).

When I try to record from the headset mike, using 
arecord -D hwplug:1,0 -f cd
I get a very loud, frequent (maybe 4 Hz) ticking superimposed upon the
sound.

It's not a hardware problem, because if I record using the legacy
sound device by 
cat /dev/audio1
I don't get this ticking.

Any suggestions for what I can do to solve this?