Denon PMA-350 / PMA-350Z (1973–1975)
The Denon PMA-350 name shows up on at least two distinctly different amplifiers, and the record doesn't cleanly separate them. The best-documented one is the PMA-350Z, a 1970s integrated amplifier built in Japan around 1973-1975. The Vintage Knob describes it as an update of the earlier PMA-300, part of Denon's small "Z" series offering, and says it was also sold in Japan as the PMA-300ZA. A separate PMA-350II appeared in the early 1990s budget wars, and a PMA-350SE also exists from that era. Those are different machines.
Here is what's documented for the 1970s PMA-350Z. It's a solid-state pre-main amplifier rated at 31W per channel into 8Ω (single-channel drive) or 27W + 27W with both channels driven, at 0.1% THD. The power amp section is a pure complementary OCL circuit with Darlington power transistors (Motorola PNP-NPN pairs). It's direct-coupled with no output capacitor and has a dual power supply, which gives a low output impedance of 0.15Ω or less. The preamp section uses high-voltage low-noise transistors, an NF-type tone control circuit with FETs in the intermediate stage, and an 11-position click-stop volume control. It has two phono inputs (MM), two tape decks with monitor and dubbing, low and high filters, loudness, and a −20dB audio muting switch. Frequency response is rated at 8Hz - 150kHz ±0.5dB, RIAA deviation within ±0.5dB, and S/N at 62dB (phono) or 73dB (line). Dimensions are 430 × 140 × 350mm, weight 10.5kg, power consumption 60W. The Vintage Knob notes it was "pretty in wood" with switchable pre/main separation.
The later PMA-350II (early 1990s) is a separate design, a budget integrated amp with A/B speaker switching, tone defeat, and loudness. A period review in HiFi Review (early 1990s) found the 350II nicely finished, better than equivalent Pioneer or Marantz offerings at the price, and mentioned a £60 price increase over the original PMA-350. The reviewer knew the cheaper PMA-250/III well and admitted never having encountered the original 350.
Known specs for the 1970s PMA-350Z:
- Rated output: 31W/31W (8Ω, single channel), 27W + 27W (both channels), THD 0.1%
- Frequency response: 8Hz–150kHz ±0.5dB
- Input sensitivity: 1V/90kΩ (line), 2mV/60kΩ (phono)
- S/N: 62dB (phono), 73dB (line)
- Dimensions: 430 × 140 × 350mm, 10.5kg
- Original price: ¥62,000 (around 1973)
If you're looking at a unit, the wood-clad, Z-series model with the click-stop volume is the 1970s original. The minimalist black or grey-faced one with A/B speaker buttons is the 1990s reissue. Both are legitimate Denon amps, but they aren't the same amp.
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