Marantz - DPM-7 - Digital Processing Amplifier - Prototype - made by Philips/Marantz R&D - Solid state power amplifier

Marantz DPM-7 – Digital Processing Amplifier – Prototype (Philips / Marantz R&D, 1985)

Offered is an original Marantz DPM-7 prototype, developed within the joint Philips & Marantz R&D program in the mid-1980s. This device is not a commercial product, but a rare development model of which only a limited number of test units were built.

The DPM-7 is laid out as a hybrid digital-analog design, combining experimental digital signal processing with a full, conventional analog final amplifier. The final amplifier section is built with an original, self-contained Marantz power-amp PCB, comparable to the regular Marantz architecture from the same period. Only 60 fully functional DPM-7s are in circulation.

Functional status of this unit
• Final amplifier: fully operational and tested.
Suitable for normal musical use as a standalone stereo final amplifier.
• Spectrum display / graphic analyzer: active and functioning.
• Volume control and basic operation: functional.
• Other digital/DSP-related functions: not demonstrably active and not further tested. These functions are hardware-present, but the operational status is unknown.

Important distinction
The final amplifier section operates independently of the digital experimental modules. As a result, the unit is not only interesting as a development prototype, but also practically suitable for listening.

Technical context:
• Hybrid digital-analog design
• Analog stereo final stage with classic Marantz construction
• Digital control and signal modules as an R&D platform
• Digital signal philosophy around 44.1 kHz / 16-bit
• Real-time spectrum visualization
• Prototype implementation: functionality may vary per unit

Available (not confirmed active) development modules
• DSP architecture (Audio Signal Processor concept)
• Graphic Equalizer with presets (m1 through m4)
• Dynamic level / release-time parameters
• Reverberation / absorption parameters
• Special effect selector

These modules are part of the original design, are physically present at the PCB level and on the front panel, but not confirmed active.

Assembly
• Fully metal chassis
• Generous ventilation section on the top plate
• Advanced front display with segment control
• Expanded front panel with parameter-controlled operation

Cosmetic condition
Clean and well-kept. Front panel in good condition with clear markings. Signs of use appropriate to age and prototype status. Physical specifications:
• Year of manufacture: 1985
• Weight: approx. 18 kg
• Dimensions: approx. 43 cm wide × 18 cm high
• Brand: Marantz / Philips

Includes
• R&D schematics made at the time by a professor who worked at Philips and thus obtained the object
• Power cord

Carefully packed and shipped insured.