Hafler DH-500K
A power amplifier sold as a kit for $599.95. That price pushed a lot of audiophiles to pick up a soldering iron.
Overview
The DH-500K is the kit version of Hafler's DH-500 power amplifier, and the price gap between the two says most of it. Throughout the early-to-mid 1980s, mail-order dealers listed the DH-500K at $599.95 against $749.95 for the factory-assembled DH-500A. That is a $150 spread, and buyers were expected to close it themselves with a soldering iron and a free weekend. Oxford Audio Consultants, a long-running Hafler mail-order house, ran those numbers in full-page ads in Audio for years, and the K-suffix kit consistently undercut the assembled A-suffix unit by that same margin.
What the buyer got for the money was Hafler's big black box. High Fidelity (July 1982, p.31) described the DH-500 as a 19-by-7-inch front panel, 10¼ inches deep, "in metal case," with clearance needed for handles and connections. That review also noted the DH-502 bridging adapter, a $25 accessory not tested in that report, which let owners turn the stereo amp into a bridged mono block. The review framed the DH-500 against Hafler's earlier DH-200, which the same magazine had praised in its March 1980 issue for the combination of value and performance. The DH-500 was the bigger brother in that same value-first lineage.
The kit pricing drifted upward over the years, and the ads track it. In September 1981, Oxford listed the DH-500K at $599.95. By February 1988 the same dealer had it at $725, with the assembled DH-500 at $850. A private seller in a March 1982 classified had a DH-500K at $515, so the kit price was a starting point, not a floor. The K-suffix units carried Hafler's three-year warranty on assembled units per the dealer advertising (the "no suffix" assembled units, that is), while the kit itself was a build-it-yourself proposition.
One detail collectors should note: the DH-500K was a kit, and kits get built by amateurs. A used DH-500K is only as good as the person who assembled it. Solder joints, transistor mounting, and bias adjustment are all on the owner, not the factory. That is the single biggest reason K-suffix Haflers trade below their assembled siblings on the used market, and why a clean, well-built kit is worth seeking out specifically.
The DH-500 line also had a modification culture around it. A 1982 Audio classified advertised a DH-203 "200/500 mod kit" for $11.95 (or $9.95 each in quantity), and Musical Concepts sold a "Super Mod" preamp kit alongside an amp mod kit for the DH-200. Hafler power amps were clearly treated as a platform, not a finished product. Whether those mods improved anything is a matter of opinion.
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