Adcom GFA-545II (circa 1991)
Documentation on the Adcom GFA-545II is thin. What survives comes almost entirely from a pair of advertisements the company ran in Audio magazine in 1991. The ads pitch the 545II as a refined successor to the GFA-545, a model that had already built a reputation for serious power at a reasonable price. Adcom claimed the 545II drew on field experience with “thousands of GFA-545s” in service, which let the engineers dial in both audible detail and long-term reliability (Audio, May 1991, p.22).
The amplifier is described as a “high current” design with a substantial power supply (Audio, October 1991, p.102). It has two protection features that were still notable at the time. One is an instantaneous distortion alert shown by front-panel LEDs. The other is thermal protection that shuts the amplifier down when it overheats, then restores operation automatically once the temperature drops to a safe level (Audio, October 1991, p.102).
The known facts are few:
- High-current power amplifier, stereo (Audio, May 1991, p.23)
- Continuous power, 20 Hz – 20 kHz, <0.04% THD into 8 ohms (exact wattage not fully legible in surviving period sources) (Audio, October 1991, p.102)
- Front-panel LEDs for instantaneous distortion alert
- Automatic thermal protection with auto-restart
- Advertised in Audio May 1991 and October 1991
Beyond those advertisements, almost nothing else is recorded. No service manual, no schematic and no measured review from an independent publication has surfaced in the archive. The GFA-545II appears to have been a brief, evolutionary update to Adcom's popular mid-range power amplifier line before the company moved on to later models.
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