Soundcraftsmen PM860
A MOSFET amp rated at 205 watts into 8 ohms that handles 2-ohm loads, with a list price under six hundred dollars.
Overview
Soundcraftsmen built its reputation on high-current MOSFET output stages, and the PM860 carried that argument into working studios, clubs, and custom installs. The headline number is 205 watts per channel into 8 ohms across the full 20 Hz-20 kHz band at under 0.05% THD. The figure that mattered to the company sat at the bottom of the impedance curve: 450 watts per channel into 2 ohms. Soundcraftsmen's own advertising led with that spec.
The company's period advertising reasoned that loudspeakers have a "dynamic" impedance that can dip as low as 2 ohms even when the nominal figure reads 4 or 8. An amplifier that can't feed those dips audibly compresses the music and roughens high-level passages. Soundcraftsmen claimed ultra-high-current capability of over 72 amps to keep the output solid into those loads. Whether or not owners ever drove a real speaker down to 2 ohms, the headroom was there.
DB (1986, p.37) laid out the full published spec sheet: a two-channel 205-watt design with a 20 Hz–20 kHz power bandwidth, IM and THD of 0.05% at both 1/4 watt and full rated power, frequency response of 20 Hz–20 kHz ±0.1 dB, a signal-to-noise ratio of 105 dB, and high-level sensitivity of 1.5V. The same listing noted the 450-watt 2-ohm rating, a two-speed fan, clip indicators for each channel, and an optional rack-mount/cabinet panel. Dimensions were listed at 5 x 8.5 x 14 inches, weight 22 lbs, price $549.00.
The DB listing shows $549.00. Collectors note the spread - street and list pricing moved around across the model's run, and what a buyer actually paid depended on the dealer and the year. None of these figures makes the amp cheap, but for a high-current MOSFET design rated to 2 ohms it was aggressive.
DB (1991, p.35) returned to the PM860 years later for a full Lab Report, describing it as a professional 800-watt MOSFET power amplifier rated 300 watts per channel into 4 ohms — a reminder that the 4-ohm figure was the one pro users cared about, and that the "800-watt" billing refers to total multi-channel capability rather than a per-channel number. In the measurement portion of that same report (DB, 1991, p.38), the reviewer confirmed the 205-watts-per-channel-into-8-ohms rating and measured an A-weighted signal-to-noise ratio of 101.7 dB on one channel and 100 dB on the other. Input sensitivity for 1 watt into 8 ohms came in at 91 millivolts. The reviewer also noted that over several hours of listening the fan's high-speed mode never kicked in and the clip indicators never lit — a good sign for a home or studio user who wants the headroom without the noise.
Soundcraftsmen's chief engineer, Paul Rolfes, was credited in company literature with a string of amplifier "firsts," including signal-tracking multiple-rail power supplies, fully electronic automatic resetting crowbar protection, Phase-Control-Regulation power supplies, and automatic low-impedance power supply selection. The PM860 sits within that PCR tradition - Sound & Communication (1986, p.42) described it as combining PCR technology with Power MOSFET output circuitry. The amp is also part of the broader X2 Series family, which included the 450X2, the 450X2M with calibrated LED metering, the 900X2, and the four-channel PM860X2. The PM860 is the two-channel member of that group, and the family shared the same MOSFET, no-current-limiting design approach.
Soundcraftsmen's literature argued that current-limited amplifiers produce harsh clipping, and that leaving the output stage unrestricted gives cleaner behavior when pushed. That is a design choice with real tradeoffs, since protection circuitry exists for a reason, but it fits the high-current, low-impedance story the company told across the line.
For a collector or studio owner today, the PM860 is a solid, unfussy choice: 22 lbs, a rack-mount option, clip indicators, a two-speed fan, and a genuine 2-ohm rating. It isn't a lifestyle piece and it never pretended to be. It's the kind of amplifier that gets bolted into a rack and forgotten about, which is roughly the highest compliment a working amp can receive.
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