What was the first power cable that you noticed a difference in the sound?

Kubala Sosna Elation! I think they are $2500.

Shunyata Black Mamba on sources and 2 BMI Whale Elite on amp which requires 2 power cords. Much quieter back drop the music was presented in. I still have them. I use Wireworld Silver Electra 7's on my digital front end now. 

ZU Event Power Cables. Not an improvement of sound character so to speak (low, mids, highs, etc). The improvement came with much lower noise. The music seemed to come out of more darkness. Very subtle but worth it. 

Audio Envy Ocean Elite Expanded With OCC ground upgrade.  Music just took several very quiet steps out into the room.  Extremely nice cables at such reasonable prices.  OCC wire , quality insulation, gold plated solid copper tight fitting connectors and very light and flexible cable.

For the DIYers out there...

1. Furutech bulk cables - better than stock cables, but that’s about it
2. DH Labs Bulk cable - just as good as furutech, but much more affordable
3. My own Helix IMAGE DIY AIR geometry cables
   • Helix IMAGE DIY power cable
   • these took my system into a whole new performance level
     • spacious - a true 3D image
     • dynamic
     • detailed
     • low noise floor
     • deep articulate bass

They get a little on the expensive side when you get into the OCC copper, but you can try them using plain old romex house wire first for a more affordable approach just to "prove the theory"

Read what other Audiogon members think about the Helix DIY cables here...

• Duelund conversion to DIY Helix Geometry Cabling

Enjoy the read :-)

Regards - Steve