Constellation Audio / Reference series – Hercules II Stéréo

Features

500 watts per channel into 8 ohms
Our 500-watt/8-ohm per-channel power rating for the Hercules II Stereo is actually pretty conservative; it’s really more like 550 watts. And 750 watts into 4 ohms, and a full 1 kW into 2 ohms. Thanks to its increased power supply capacitance and ample cooling capacity, the Hercules II Stereo drives low-impedance speakers with ease.

Modular circuit concept
Instead of achieving the Hercules II Stereo’s in the traditional way—just bulking it up with more output devices—we build it from numerous 125-watt single-ended modules. It thus has the musicality of smaller amplifier, and the power and control of a large amplifier.

Balanced drive design for superior musicality
In the Hercules II Stereo, as in all Constellation Audio amplifiers, both the positive and negative halves of the audio signal see exactly the same type of output devices: N-type transistors. In other amps, the transistors are half N-type and half P-type, resulting in an inherent signal imbalance.

Inherently stable circuit design
Our circuit design combines high bandwidth with inherent high stability. Unlike many high-powered amplifiers, the Hercules II Stereo does not need a Zobel network at the output terminals to ensure stability at high frequencies.

Dual-mono design with one 3,000-watt transformer per channel
Each of the Hercules II Stereo’s channels has its own custom-wound, 3,000-watt toroidal transformer. Both transformers contain multiple isolated sets of windings to supply independent power feeds to various circuits within the amplifier. The isolation of the windings assures consistent voltage and current supply to all of the amplifier’s circuits, regardless of the demand placed on those circuits. Because each channel has its own transformer and supply capacitors, it is unaffected by the operation of the other channel.

High-efficiency passive cooling
With more than 1,000 watts total power into 8 ohms, the Hercules II Stereo demands a constant, free-flowing supply of cool air. To achieve this without the use of fans, we incorporate two huge heat sinks and hundreds of large ventilation ports to minimize airflow impedance and maximum cooling.

Perfect balancing through Line Stage Gain Module
The Hercules II Stereo incorporates two Line Stage Gain Modules, one for each channel. This module uses servo circuits and hand-selected FETs to assure that all incoming signals are perfectly balanced by the time they reach the amplifier stages. This is the same exact circuit found in our Altair II and Virgo line stages, and in all of our source components.

Constellation Direct balanced interface
If you are using a Constellation Audio preamplifiers, you can use the Hercules II Stereo’s Constellation Direct input. This input bypasses the amplifier’s Line Gain Stage Module, which simplifies the audio chain for the best possible detail and musicality.