The Marantz HD-AMP1 sits within Marantz's compact HD series, designed to deliver reference-grade performance in a smaller chassis than the brand's traditional full-width components. It combines a high-resolution DAC section with an integrated amplifier and a dedicated headphone stage, making it equally suited to desktop and traditional hi-fi use.
DAC and digital architecture
The digital section is built around an ESS SABRE ES9010K2M DAC, paired with Marantz Musical Digital Filtering and dual master clock crystals for the widest bandwidth and lowest distortion. The rear USB-B input operates in asynchronous mode with advanced noise isolation, accepting PCM signals up to 384kHz/32-bit and DSD streams at 2.8, 5.6 and 11.2 MHz. Two optical inputs and a single coaxial input handle PCM up to 192kHz/24-bit, and a front-panel USB-A port provides direct connection and charging for Apple devices.
Amplification
The HD-AMP1 uses cool-running Class D amplification rated at 35W per channel into 8 Ohms and 70W per channel into 4 Ohms, with the current capability to drive low-impedance loudspeakers. Marantz's exclusive HDAM-SA2 discrete current-feedback modules feature across three circuit blocks, including the analogue front end and the D/A converter I/V stage, keeping the signal path short. Quoted signal-to-noise ratio is 105dB with total harmonic distortion of 0.05%.
Headphone amplifier and connectivity
The front-panel headphone output has its own HDAM-SA2 stage, a three-position gain switch (low, mid and high) and independent volume control, allowing the HD-AMP1 to drive everything from low-impedance in-ears to demanding high-impedance models. Two gold-plated analogue RCA inputs sit alongside the digital connections, and a subwoofer output allows a powered sub to be added. A ground isolator function reduces ground loop noise when the unit is connected to a computer.
Construction
The chassis pairs a brushed aluminium front panel with woodtone side panels and the exclusive Marantz two-line porthole display, which offers three dimming levels. Speaker connections use Marantz's premium SPKT-1 terminals, compatible with speakers rated between 4 and 16 Ohms.
