Hafler DH-200 Power Amplifier — 100 WPC MOSFET, Made in USA

David Hafler’s second act, and the amplifier that put MOSFETs into American hi-fi.

Hafler had already built one legend at Dynaco with the ST-70, and when he started again under his own name at the end of the 1970s the DH-200 was the power amplifier that followed. Walt Jung, reviewing it for The Audio Amateur in 1980, noted it was the first American production amplifier he knew of to use complementary MOSFETs in its output stage — which is why this plain black box turns up in conversations about amplifiers costing many times as much.

MOSFETs are the reason it behaves the way it does. They have no thermal runaway and act as low-value resistors when switched on, so the DH-200 needs none of the voltage-current limiting circuitry that bipolar amplifiers of the era relied on. Nothing sits between the output stage and your speakers clamping down on transients. It is also why the amplifier shrugs off loads that made contemporaries fold.

The rating is 100 watts per channel into 8 ohms, and it is a conservative rating. Jung measured over 130 watts per channel at clipping on his bench in 1980, and around 250 watts from a single channel into 4 ohms. Ken Rockwell, measuring a different sample decades later, got 116 watts continuous and 164 watts on burst. Two independent benches, forty years apart, both finding more than the badge claims.

The distortion figures were extraordinary for the price and remain respectable now — the specification is 0.012% total harmonic distortion, and Jung’s bench found it sitting near the residual noise floor of his analyser across most of the audio band. Intermodulation measured at the limits of what his equipment could resolve.

Construction is honest rather than showy. A heavy transformer feeds a 25-amp bridge rectifier and unregulated ±60-volt supplies. The two channels live on the left and right heatsink assemblies, which double as the end panels of the chassis. Protection is layered — a mains fuse, thermal breakers that sense heatsink temperature and shut the amplifier down, individual supply fuses per channel, and speaker fuses inside the feedback loop.

Jung was not uncritical. He heard a high-frequency character on his own system that he called sizzle, and said so at length — though other reviewers of the period reported not hearing it, and he was clear that it depended heavily on the cables and speakers around it. His conclusion on value was unambiguous: at the price, he wrote, it was “one whale of a lot of amplifier.” That is the useful verdict, from someone who had just spent two thousand words telling you exactly what he did not like.

It sold new in 1980 at $429.95 US assembled — about $1,650 in 2026 Canadian dollars — or $329.95 as a kit, the kits arriving with the amplifier modules already built and tested.

Built in Pennsauken, New Jersey. At 26 pounds in a 5-inch-high chassis it is compact for its output, and it stacks or shelves easily.

Condition is Very Good.

A few relevant specifications:

An American-built MOSFET amplifier from one of the two or three designers whose names still mean something, measuring better than its badge on every bench that has tested one.

Available for pickup in Kanata, or shipped across Canada and internationally — we have sent equipment to fifteen countries in the past year, each piece packed in-house in 275 lb test double-wall boxes. Live shipping rates for your address are calculated at checkout. Backed by Radique Audio’s Bumper-to-Bumper Warranty and our Perpetual Trade-Back Program. Available for audition by appointment in Kanata.

Hafler DH-200 stereo power amplifier, stock Specifications

• Stereo power amplifier, MOSFET output stage
• Power output 100 watts per channel into 8 ohms; 175 watts per channel into 4 ohms
• Total harmonic distortion 0.012%
• Frequency response 10 Hz to 40 kHz
• Signal-to-noise ratio 100 dB
• Input sensitivity 1.5 V
• Damping factor 50
• Semiconductor complement: 26 transistors, 8 MOSFETs, 24 diodes, 4 zener diodes, 1 bridge rectifier
• Thermal shutdown with front-panel indicator; per-channel supply fuses and speaker fuses
• Made in the United States of America
• Dimensions: (Width x Height x Depth) 16 x 5.125 x 10.5 inches (40.6 x 13 x 26.7 cm)
• Weight: 26 lbs (11.8 kg)

⚠️ Important Information for International Buyers

This unit is configured for North American 110/120V power. Buyers outside North America will require a step-down transformer and appropriate plug adapter.

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