Keantoken Kuartlotron
http://www.startfetch.com/keantoken/content/Kuartlotron.php
The Kuartlotron -
An RFI-Resistant Hi-Fi No-Feedback Audio Signal Buffer
This buffer uses error correction rather than feedback, allowing it to have amazingly low distortion while being simple, low-noise and nearly as fast as a single transistor! RF noise poses no trouble for it.