Heros

About the Heros

The Thrax Audio Heros is a high-end hybrid Class A mono power amplifier. It uses a differential vacuum-tube voltage-gain stage followed by a transformer-loaded cascoded JFET/MOSFET current-output stage. Signal handling is fully differential from the input phase-splitting transformer through the push-pull output transformer, with transformer-coupled RCA and XLR inputs. The design provides switchable gain/input sensitivity and switchable 4-ohm or 8-ohm loudspeaker transformer taps. Its machined aluminium chassis also functions as the heat sink. Current manufacturer information identifies the evolved model as the Heros MK2; the original Heros specifications below are drawn from the original brochure/manual and period documentation. Some published documents differ on physical dimensions, weight, and whether the tube is designated 5687/5687WA or 6N6P, likely reflecting production revisions and/or documentation inconsistencies.