Simply put, the Hydras use a 20 amp IEC input (horizontal pins instead of the vertical 15 amp variety) because the 20 amp connection is more secure and less prone to pull loose if jostled. There is no over or under limitation between any Hydra and a 15 amp panel breaker. The Hydra 4, 6 and 8 models will not exceed 20 amps of service because of the 20 amp rated electromagnetic Carling breaker, which will trip when the 20 amp threshold is crossed. Musical Fidelity, Krell, Chord and a few other manufacturers also use 20 amp input connectors for similar reasons.
Grant
Shunyata Research
Grant
Shunyata Research