Halcro Eclipse Mono Power Amplifiers


The new Halcro team have spent the past couple of years exploring every aspect of the unique platform for possible improvements. We present – the new reference in amplification.

Available in both stereo and mono versions, the Eclipse series is unparalleled in its ability to render details formerly lost in the distortion.

The Eclipse enjoys a completely redesigned input stage, further reducing non-linear effects and distortion. There are multiple independently tracking power supplies, superior internal shielding and higher output power. Finally the Eclipse amplifier offers a new, modern, ‘lighter’ take on the distinctive and award winning Halcro aesthetic. Even this contributes to better performance with the new, machined-from-solid casework reducing microphonics.

Halcro amplifiers offer an unmatched insight into the music. They position everything precisely in the soundstage due to their unique ability to avoid adding ‘ghost’ notes that are thrown into the mix by the non-linear distortion of a conventional amplifier. Lack of distortion aside, one of the many things that make Halcro amplifiers so good is the way they maintain the phase coherence of the signal source. Phase coherence is a measure of the degree to which a system maintains the relative timing of various notes or tones within complex music.

When it comes to driving your loudspeakers musically, the Eclipse has no peer. The Eclipse mono produces 300 watts/per channel into an eight-ohm loudspeaker, 550 watts/channel into four-ohms with a peak power of 2.1kW for the most dynamic of transients.

Beyond all the technology, there is only one thing that matters: the ability to convey the emotion of music.


• 4 ohms (resistive) approx. 550W • 8 ohms (resistive) approx. 300W

DISTORTION (Footnote 1)

• At full power output, all harmonic distortion orders.
• THD <-126dB (< 500 parts per billion) up to 20 kHz (100 kHz BW) at 550W into 4 ohms
• THD @ 1kHz is <-140dB (<100 parts per billion)
• For a sum of 19 and 20 kHz tones, each delivering 100W into 4 ohms = peak power 550W, intermodulation products each < -126dB relative to output.
• SMPTE-IM Intermodulation products each <-126dB relative to output


There are 4 input modes:
• An unbalanced voltage mode input with an impedance of 100 kOhm
• A balanced voltage mode input with an impedance of 100 kOhms +100 kOhms
• A current-mode input with a 60 ohm input impedance to minimize cable reflections (driven by current source) • A minimal path voltage mode with an input impedance of 660 ohms.


• Balanced and unbalanced inputs 60V/V • Minimal path input 30V/V
• Current mode input 9V/mA


There are 4 heavily shielded compartments: • A power supply unit
• An input amplifier section
• A power amplifier compartment

• An output filter compartment

POWER SUPPLY (Footnote 2)

• Active power factor correction minimizes mains current harmonic distortion
• Less than 100 parts per million mains hum and ripple on the amplifier power rails
• Conforms with all current emission and safety standards
• Operates at all voltages from 85 through to 270V r.m.s. 45-65Hz, without any internal or external switches

COMPONENTS (Footnote 3)

• For reliability, all semiconductors are at least industrial grade in both the power supply and amplifier.
• All electrolytics are rated to 105°C in both the amplifier and power supply.
• Only highly linear resistors and the lowest impedance polypropylene capacitors are employed in the critical audio path.
• Six-layer PCBs are used in the power amplifier to minimize stray magnetic fields to accurately define voltages.
• Four-layer PCBs are used in the power supply to minimize E.M.I. and voltage transients, which improves reliability and power efficiency.


The amplifier protection:

• Will cut out if temperature is excessive
• Will cut out if output current exceeds 12A average continuously over a period of a few minutes • Is short-circuit proof
• Has over current limiting
• Will cut out if a continuous D.C. offset appears on output
• Is protected against most input overloads

The power supply protection:

• Will cut out if most common faults are detected in the power supply (e.g. over-voltage, master clock at incorrect frequency, excessive temperatures etc)
• Is protected against most mains transients

OVERLOAD (Footnote 4)

• Recovery from hard overload at 20kHz into 4 ohms: 1μs.
• The equivalent input noise at the input is 5nV/sqrt(Hz) for the voltage modes and 6pA/sqrt(Hz) for the current mode.


• Maximum slew rate for both small signal and maximum output voltage is 100V/μs, (which is equivalent to a maximum output voltage at approximately 250kHz.)