Denon PMA-717 (1984–86)
A slim, Class-A integrated with a phono stage that punches far above its 35-watt rating, and a production date that's been argued about for years.
Overview
Denon's own service documentation for the PMA-717 is dated April 1984 and issued under the Nippon Columbia name. That's about as close to a birth certificate as this amplifier is going to get. The 35 watts per channel into 8 ohms, both channels driven, doesn't sound like much on paper. But this is a Class-A integrated transistor amplifier, and the rating comes with a minimum RMS guarantee of under 0.05% total harmonic distortion from 20 Hz to 20 kHz. Owners who've lived with one tend to describe the sound as bigger than the number suggests, and the reason is in the circuit, not the spec sheet.
It's a slim, understated box. One HiFi Engine reviewer called it "a nice slim amplifier" and added that they liked the design, the build quality, and the way it sounded. That kind of comment shows up repeatedly with this model: not effusive, just quietly satisfied. It's not a legend the way a vintage Marantz receiver is a legend, and Denon never marketed it as one.
The date is where things get murky. HiFi Engine lists production as 1984-86. A Russian Avito listing and Retrotronics both tag a specific unit as 1985. The VTA research page that seeded this entry claims 1997, which conflicts with the manufacturer's own service manual and with every other source that names a year. The 1984-86 window is the one to trust.
Key Features
Class-A Integrated Transistor Design
Classic Audio classifies the PMA-717 as a Class-A integrated transistor amplifier. HiFi Engine calls it a solid-state pre-main amplifier. Either way, it's a discrete design, and the preamp section is DC-coupled with minimal components in the chain. That gives low phase shift and preserved transient detail. The service manual's parts lists show a JRC NJM4558D dual op-amp in the power and control unit, so it's not a purist no-IC design. The amplifier stages themselves are built around discrete transistors.
Moving-Coil-Capable Phono Stage
Retrotronics described the phono section as "excellent" with moving coil capability, and Classic Audio's spec listing gives the MM input RIAA deviation at ±0.5 dB. That's tight equalization for a mid-tier integrated, and it's the single feature most often cited by people who own one. The service manual lists the MM input at 2.5 mV into 47 kΩ and an MC input at 0.2 mV into 100 Ω, with a signal-to-noise ratio of 86 dB on MM and 70 dB on MC. Line-level inputs sit at 96 dB SNR. For a listener running a low-output moving coil, no outboard step-up is needed.
Slim Chassis and Internal Layout
The amplifier sits in a slim case measuring 434 mm (W) x 97.5 mm (H) x 286 mm (D). The internal exploded views show a front chassis, side chassis, and a separate transformer chassis, with the power transformer mounted on its own bracket. The rear panel detaches for internal access, and the service manual walks through the steps. The design assumes someone will eventually be inside it, which is more than you can say for a lot of 1980s gear.
Power Supply and Protection
The power amplifier section is rated at 35 watts minimum RMS per channel into 8 ohms, 20 Hz - 20 kHz, with THD under 0.05%. The IEC one-kilowatt test figure is 40 W + 40 W into 8 ohms. Output impedance is 0.16 ohms at 1 kHz. Speaker terminals accept 8-16 ohm loads across two switched pairs, and there's a stereo headphone jack rated at 140 mW into 8 ohms. One HiFi Engine reviewer's advice was "if you don't need many inputs and can live with 8 ohms for the speakers, give it a chance." That fits: this is not an amplifier for someone with a rack full of sources and a pair of 4-ohm electrostatics.
Historical Context
Denon built the PMA-717 as part of a tiered amplifier range. The research page places it below flagship models like the PMA-910 and PMA-850, sharing the toroidal transformer and discrete circuitry of those higher-end units while omitting refinements such as balanced XLR inputs and advanced protection circuits. The service manual, issued by Nippon Columbia in April 1984, covers regional variants for Europe, the UK, the USA, and Asia, so this was not a Japan-only model. The research page notes widespread use in Japan and Europe, and the manual's multi-voltage power source listing (110/120/220/240 V, 50/60 Hz, multiple) confirms Denon expected this amplifier to travel.
Collectibility & Value
The research page notes the PMA-717 is not a legendary model in the same vein as vintage Marantz or Sansui receivers. It also notes many units still functioning perfectly over 25 years after manufacture. Current market prices for well-maintained examples reportedly run $200 - $400 USD depending on condition and region, with a slight premium for units that still have their original packaging and documentation, particularly in Japan. A recent eBay listing for a working example sat at $127, so the floor is lower than the research page's range suggests. An Avito listing in St. Petersburg asked 20,000 ₽.
Common issues are the usual ones for gear this age: aging electrolytic capacitors and worn potentiometers. Recapping the power supply and cleaning the volume pot and input selector switch covers most of it. Replacement parts and service documentation are reportedly relatively accessible, and the service manual PDF is available at archive.org. One seller described a unit as having "some scratches on the top and general wear due to age," and cosmetic condition varies widely.
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