Heathkit AA-1800

Documentation on the Heathkit AA-1800 is thin, and even the basics take some care. Two independent sources identify it as a stereo power amplifier. Output is 150 watts per channel, with a damping factor of 200. That's about where the verified record ends.

The informal record and the period press don't line up on this one. The fact sheet's sources are a head-fi.org forum thread and a vacuum tube listing page. They call it "the big 150wpc Heathkit" and "the 150wpc monster," and one owner notes it "works well as a subwoofer amp." Those are enthusiast reports, not measured reviews. Audio (September 1982, p.57) profiled the AA-1800 and found the "rough or edgy kind of high response associated with solid-state circuitry seems absent." It measured distortion at just under 0.003% at 20 Hz and approximately 0.02% at 20 kHz, with SMPTE-IM distortion at 0.014%. The same review reported "amazingly high headroom," permitting peaks of 500 watts per channel or more before noticeable clipping. That sits oddly against the 150 wpc forum consensus, and the available sources don't reconcile the two.

The record is contradictory and incomplete. No production years, original price, dimensions, or circuit details survive in the sources. The Audio profile suggests a well-measured amplifier, while the forum chatter points to a workhorse used for subwoofer duty. Both may be true. What can be confirmed: