Living Sounds Audio Discovery Warp-1 power amplifier
It takes a while for audio-related technologies to mature. Tubed amplifiers were invented by Lee de Forest in the nineteen-teens, but while there are still some adherents of early high-distortion triode designs, the age of mainstream high-fidelity amplification dawned with higher-power/lower-distortion amplifiers developed by Williamson and McIntosh followed by the Ultralinear take on the Williamson concept. That was 30+ years down the technology-evolution timeline after de Forest.
Source: stereophile.com
