Sound Card Recommendations for the iMac

Hellofidelity and Arni: Just a follow-up note on the solution. I had upgraded to iTunes 9.0 and the trouble started. Today a buddy came over and suggested we see if iTunes had another upgrade. Impossible, I thought - its only been about a week. Sure enough 9.1.1 was available. We downloaded and problem solved. Music sounds great again. Thanks for you input, I appreciated it.

Hellofidelity: Thank you for the response. I have an iMac 8.1 Intel Duo. It does have optical/usb/firewire capabilities. I am currently using a Pop Pulse USB to SPDIF converter (it also converts the Toslink) which has worked well up until about a week ago. Thank you for clearing up the DAC/external sound card issue. I never did get that straight.

Can I assume then that an external sound card puts "out" a digital signal and then my headset amp and/or big system processor does the D/A conversion?

And finally . . . .let's assume that my internal sound card is the issue then would coming out with USB or Toslink to an external sound card actually bypass the internal sound card?

It isn't a matter of wanting to improve on the Mac Core Audio set-up - it has worked wonderfully well for the last 3 years. It is just a matter of trying to correct a sudden degradation in the sound quality over the last two weeks. The problem lies within the Mac itself, not my other equipment, so I am making the assumption that there is a glitch in the basic Core Audio portion of OSX. My thinking was that an external sound card would "go around" the internal Mac and once again restore good quality sound.

Maybe others have had this experience??

Thank you Arni - Yes, I recently upgraded to iTunes 9 - hadn't thought about that. How did you correct the problem after upgrading to a newer ITunes version? Maybe you are right on the mark.

thanks Arni I'll check into it!! Hope it doesn't destroy all the album artwork!

Do either of you know how to go "backwards" and restore an older version of iTunes? As I stated above the improvement with the newest version is good but maybe I'm getting to picky since I still think I'm hearing some issues.

Tomjoe - that is always a possibility but today I finally figured out the rest of the problem. I had left the iTunes Equalizer on - it is normally off. I was playing around with it a while back. Once I turned it off the music became instantly crystal clear. So I think the problem was twofold - some issues with iTunes 9.0 and the Equalizer. I'm listening now and it sounds great through the headset. It is my experience that listening through the headset is the quickest way to hear a problem.

Thanks again for all of your suggestions - they were valid ideas!