Nakamichi PA-5

Name: Nakamichi PA-5
Brand: Nakamichi

The Nakamichi PA-5 was the flagship power amplifier of Nakamichi's 1980s separates line, sitting above the later PA-7 as the company's top amp in its "5 series." It is a dual-mono design with a separate power transformer for each channel - two 470 VA units with 40,000 µF of total filter capacitance. It runs in class A up to 10 watts, then slides into class AB. Large external heat sinks line the sides, and a relay protects the speakers from DC offset on the output. The front panel carries LED indicators for power and clipping.

The amplifier is rated at 2×100W into 8Ω, 2×150W into 4Ω, and 2×200W into 2Ω, with total harmonic distortion below 0.005% at rated power from 20Hz to 20kHz. Signal-to-noise is listed at 120 dB (IHF A), damping factor at 100 (8Ω, 1kHz), and input sensitivity at 1V for rated output. The chassis measures 435×150×375 mm and weighs a substantial 17.1 kg. Power consumption is rated at 470W. Nakamichi's own advertising in HiFI-Stereo (September 1986, p.45) grouped the PA-5 with the PA-7 as amplifiers with an "uncanny ability to elicit optimum performance from every loudspeaker." The ad praised the STASIS-style circuitry and isolated-ground power supplies shared with the Series-7 components.

The record on the PA-5 has a few unresolved conflicts. Sources disagree on whether the standard PA-5 offered balanced XLR inputs alongside the unbalanced RCA jacks - one database lists both, another only RCA. The manual gives frequency response as both 20Hz - 20kHz and 10Hz - 100kHz. That likely reflects a rated passband versus an extended response figure, but the tolerances weren't preserved in the excerpts. Production years and original price are not documented. The Vintage Knob notes that the PA-7 followed as the "bigger brother," but exactly when the PA-5 launched and what it cost new remain unrecorded in the available material.

Owner reports describe the sound as extremely neutral and detailed with deep bass control, and one forum comment compares it favorably to high-end Krell or Mark Levinson designs of the era. The known reliability problem is the bias trimmer potentiometers. They drift over time and can take out the output transistors if left unchecked. Replacement with multi-turn Bourns parts is the commonly recommended fix. Recapping is almost always needed by now, especially the small electrolytics near the input stage. Asking prices on the used market range from roughly $600 to $1,200 depending on condition.

Output: 2×100W (8Ω), 2×150W (4Ω), 2×200W (2Ω)
THD: <0.005% (20Hz–20kHz, rated power)
S/N: 120 dB (IHF A)
Damping factor: 100 (8Ω, 1kHz)
Input sensitivity: 1V
Dimensions: 435×150×375 mm (W×H×D)
Weight: 17.1 kg