dm78

About the dm78

The Halcro dm78 is a monoblock power amplifier designed for audiophile-grade performance. It delivers power output of more than 400 watts into 4 ohms and over 225 watts into 8 ohms resistive loads. The amplifier features exceptionally low total harmonic distortion (THD) of less than -120 dB at full power up to 20 kHz, and even lower distortion at 1 kHz. It offers three input modes: unbalanced voltage mode with 100 kohms impedance, balanced voltage mode with 100 kohms + 100 kohms impedance, and a current-mode input with 60 ohms impedance to minimize cable reflections. The voltage gain for balanced and unbalanced inputs is 60 V/V, while the current mode gain is 9 V/mA. Noise levels are extremely low, with equivalent input noise at 5 nV/sqrt(Hz) for voltage modes and 6 pA/sqrt(Hz) for current mode. The amplifier has a maximum slew rate of 100 V/µs, supporting output frequencies up to approximately 250 kHz. Its power supply includes active power factor correction, operates across a wide voltage range (85 to 270 V rms), and maintains very low mains hum and ripple. The dm78 is built with industrial-grade components for reliability and includes multiple protection features such as short-circuit proofing, overcurrent limiting, and thermal power limiting. It weighs approximately 55 kg and measures 790 x 400 x 400 mm. The dm78 is no longer in production but remains highly regarded for its sound quality and engineering excellence.