The Synergistic Research (SR) Purple fuse is the best sounding fuse I've had in my system. It is significantly better than the QSA Yellow fuse in the application I chose for testing (Modwright PS 9.0 Power Supply). While both are more resolving and articulate than the SR Orange and AHP fuses I had used previously, the QSA Yellow has a cool, clinical sonic signature, and is bright on some recordings. The SR Purple by contrast is balanced (never bright), and has a naturally (not excessively) warm sonic signature. I'm done.