Oppo UDP-205 Op Amp, Linear Power Supply

@unsound - no, I never paid much attention to tweaks, footers, etc. 
I don't know what made me even think to put them under the Oppo.  But after that, I put them under my Heed dac and they did the same thing - an added sense of harmonic richness.  Taking them out made the sound flatter and more....digital?  They're certainly cheap enough to try.  Just make sure to use a coaster or something because those things ooze.  Really. 

IMO, before you do any surgery, try a Vibrapod 3 under each foot.  I never thought much of VPs before, but it made a substantial improvement on the 205.  It brought out a greater sense of tonality and harmonic completeness.  You probably have some lying around.  Good luck.