Denon PMA-300Z (circa 1973)
The Denon PMA-300Z is a solid-state integrated amplifier from the early 1970s. It is an all-silicon transistor pre-main amp that originally sold for ¥42,800. It was positioned as a refinement of the earlier PMA-300, carrying over that model's quality while aiming for greater completeness. The record on this one is thin.
Denon's design approach here was rigorous. The PMA-300Z used a genuine complementary symmetrical output stage built around PNP/NPN pairs of Motorola silicon power transistors, paired with a Darlington configuration for perfect symmetry. The amp ran an OCL (output capacitorless) circuit with a dual power supply. It drove the speaker voice coils directly, with no coupling capacitors, which was intended to keep the damping factor high even outside the audible band. A differential amplifier using a carefully selected monolithic IC was adopted for DC stability. The tone control section used a 3-chip NF-type circuit with an FET in the middle stage. The 40V power supply voltage, equivalent to that of a standalone preamplifier, was chosen for efficient dynamic range and low-noise operation.
Specs from the period show a modest but clean performer. Music power is 22W×2 into 8Ω. Rated output is 19W per channel with a single channel driven, and 17W + 17W with both channels driven (both at 0.1% THD or less). Frequency response runs from 10Hz to 100kHz at -1dB, with a damping factor of 70 or more. The phono stage has two inputs, Phono 1 at 2.4mV sensitivity and Phono 2 at 8mV, with RIAA deviation within ±0.8dB. Tone controls give ±11dB at 80Hz (bass) and ±9.5dB at 12kHz (treble), plus low and high filters. The unit weighs 7kg and measures 376×140×302mm.
One listing from a Vietnamese YouTube title suggests the PMA-300Z "plays seo speakers very well," though no substantive review content was extracted. A vintage unit appeared on the market around $344. Current pricing and collectibility data are essentially undocumented.
Known Specifications
- Music power: 22W×2 (8Ω)
- Rated output: 19W/19W (8Ω, single-channel drive); 17W+17W (both channels driven, THD ≤0.1%)
- Frequency response: 10Hz–100kHz (-1dB at 1W)
- Damping factor: 70 or more (8Ω, 5Hz–30kHz)
- Input sensitivity: Phono 1: 2.4mV/60kΩ; Phono 2: 8mV/60kΩ; Tuner/AUX: 100mV/80kΩ
- Tone control: Bass ±11dB (80Hz), Treble ±9.5dB (12kHz)
- Filters: Low 100Hz, High 7kHz (-6dB/oct.)
- Dimensions: 376×140×302mm; Weight: 7kg
- Power consumption: 42W
What's missing: production years beyond the "around 1973" price context, any service manual details, and owner or reviewer reception. The audio-database.com listing provides the substantive record here. The archive would welcome more information, particularly on how it compares sonically to the PMA-300.
Similar items on eBay
No exact Denon PMA-300Z listings are live right now — these searches show current Denon and similar vintage audio gear on eBay:
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.
Related Models
- Denon DL-160 (1979)
- Denon PMA-717 (1984–86)
- Denon AU-310 (1975)
- Denon AU-340 (1978)
- Denon DA-401 (1975)
- Eico 3150 (1967)
- Fisher CUSTOM-ELECTRA-I (K-14/K-15) (1957)
- Fisher CUSTOM-ELECTRA IV (E33/E44) (1960)
- Akai AM-2400 (1978)
- Akai AM-2600 (1977)