Ok tried the ground loop isolator tonight and it didnt make any difference. So I hooked up my NXG NX-VM80 volume control knob between the speakers and the amp and VOILA! Perfect sound! No idea why this is, because even with the knob at 11 (max output) there is no humming, hissing, or popping. This thing cost me a pretty penny ($35 I think) but it works flawlessly. I recommend the amp kit/vol knob solution for anyone who wants REAL arcade speakers and not the usual PC speaker hack. Looks better, sounds better (IMHO of course). Thanks for all the suggestions!
ED7