Adcom GFA-555 II
The GFA-555 II is the second-generation version of Adcom's well-regarded GFA-555 stereo power amplifier. The original GFA-555 had a reputation as a breakthrough, widely judged to perform on par with amplifiers costing two and three times as much. Audio (October 1991, p.134) described the original as widely considered superior to far more expensive competition, and noted that Adcom spent years refining it before releasing the II.
The GFA-555 II is rated at 200 watts per channel into 8 ohms. According to the period advertising, it offered greater stability, improved heat dissipation, and lower distortion than its predecessor. The same advertisements claimed performance that remained a "breakthrough in value." A later HiFI-Stereo piece (April 1997, p.5) called the GFA-555 II "legendary" among audiophiles and serious music listeners. It said the amp set the standard for high-end sound at a reasonable cost and was routinely compared to amplifiers costing two or three times as much.
Adcom positioned the GFA-555 II as a stereo workhorse below the GFA-565 mono amplifier (300W/ch into 8 ohms, 400W into 4 ohms at under 0.02% THD). The 555 II was eventually succeeded by the GFA-5500, which carried the same design philosophy forward. Beyond the magazine coverage, little detailed documentation has survived in the public record. Service manuals, production years and exact pricing are all missing.
Known specifications (from period advertisements):
- Type: Stereo power amplifier
- Key improvements over GFA-555: Greater stability, superior heat dissipation, lower distortion
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