I have:

kubuntu Feisty 7.x (latest adept updated version)
KDE version:  3.5.6
System:  Linux
Release:  2.6.20-16-generic
Machine:  i686

Amarok 1.4.5 (Build date April 4, 2007)

I've been using Amarok for months with only a few issues which have all been resolved -- it's imported successfully my collection, I have lots of playlists, and it's very successfully added and deleted files on my Apple iPod Shuffle

Yesterday I decided to take the plunge and see if I could get some eyecandy working. I enabled some of the glx options in my xorg.conf file, installed the Beryl packages with Adept, and did a few restarts to get the things loaded.  But, my drivers/ATI video were not optimized, or somesuch, and rather than go through the long process to do that, I decided to back out and return to my original system. Which I have done. No more Beryl/compiz/glx stuff is loaded via xorg.conf or in applications and the Beryl packages have been removed using Adept.

But Amarok no longer plays.  Well, it loads and will begin playing files/streams, but the audio is broken and dropped **significantly** (not every 3 seconds, but more like two times a second).  Quite unusable.  For the life of me I cannot think what the connection is between the graphics libraries/apps I installed for Beryl and the audio stuff used by Amarok, but those are the only changes I made yesterday.

I have reinstalled Amarok using Adept to no affect.

NOTE: audio plays fine in aboth XMMS and RealPlayer, so it's not the audio system or libraries for mp3, etc.  It's only Amarok that has the problem.

Any ideas?

Not sure why it would be affecting playback, other than cpu stuff, but Amarok uses opengl for some of the analysers. Is it possible you've changed which opengl implementation you're using?

It had absolutely nothing to do with the graphics/display system.  I noticed after posting this that the clock was running oddly -- in fact, 50% slower (almost exactly that).  After some playing around, I confirmed that the clock at the hardware level was fine by going into my system's bios setup, where it ran the same as my reference (a timer on my pda).  But logging into either a console or to KDE resulted in the slow clock.  A post in the install/boot kubuntu forum mentioned a clock issue (running too fast in their case) that was solved by downreving the kernel to 2.6.17.x.  At some point, I cannot remember when, I used Adept and did the recommended upgrades and that included a kernel update to ver 2.6.20-16-generic. I booted my system to the 2.6.17 kernel and the clock/timing issue has disappeared.  Which shows 1. that Amarok relies on the system clock whereas RealPlayer and XMMS do not, and 2. that kernel does something really odd.  I'll cross post this to the install/book forum so if any of the kubuntu folks look there they'll see it.

good detective work