Pioneer M-1500 (1978–1980)
The Pioneer M-1500 is a compact stereo power amplifier from the late 1970s, built in Japan and sold for ¥40,000. It was the little brother in Pioneer's separates lineup of that era - the family that included the bigger M-77 and the SPEC-series separates. It has the house look of the period: a plain black faceplate with a single power meter per channel. It is a 3U rack-mount unit (480 × 142 × 290 mm, 7.7 kg), rated at 50W + 50W into 8 Ω from 20 Hz to 20 kHz with 0.05% harmonic distortion. Signal-to-noise is listed at 110 dB (IHF, A-network), damping factor 30, and input sensitivity 1V/50k Ω. The output stage is described as a first-stage differential, all-stage direct-coupled complimentary OCL design.
The M-1500 has a pair of VU-style power meters on the front panel. Pioneer fitted an electronic-circuit-and-relay protection system to guard both the speakers and the output transistors. Speaker terminals accept 4-16 Ω loads with either A or B sets engaged, or 8-16 Ω with both A and B driven together. It is a 100V unit (50/60 Hz) rated at 130W consumption.
Documentation on the M-1500 is thin outside of its specification sheet. One Russian-language owner post dismisses the 1500/1500-2/1800-2 family - "IMHO, there's nothing to catch there, because it's hackwork" - but that is a single opinion, and Russian marketplace listings describe the sound as "luxurious and detailed." A related model, the M-1800 II, was also produced around the same time (1978-80). It appears to differ from the M-1500 II by having overload indicators above the peak indicators.
Known specifications:
- Output: 50W + 50W (8 Ω, 20 Hz–20 kHz)
- THD: 0.05% (20 Hz–20 kHz, at rated output)
- IM distortion: 0.05% (60 Hz:7 kHz = 4:1)
- Frequency response: 5 Hz–40 kHz (at 1W, 0.05% distortion)
- Input sensitivity/impedance: 1V / 50k Ω
- S/N ratio: 110 dB (IHF, A-network)
- Damping factor: 30 (8 Ω)
- Dimensions: 480 × 142 × 290 mm; 7.7 kg
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.