I actually have the GC's on my amplifier (an AudioPrizm Debut with new OPT's and power supply mods) on my Sony CD/SACD player and my Planet 10 Fonken boxes with EnABL'd Fostex 127 eN drivers installed. The amplifier GC's provided about half as much back side of the wave information retention as the GC's on the speakers. The CD player GC retained the high frequency information as music, rather than the rather harsh, grainy, unmusical edge to sound that the unit came with. Not proselytizing here (much anyway) but I suspect some folks are wondering about uses in other locations and these have been my results. I do also have them in my transformer, stepped, isolated attenuator preamp, but most folks don't have one of these.
Bud
Bud