Adcom GFA-5200

Name: Adcom GFA-5200
Brand: Adcom

Fifty honest watts, a 27,000 µF capacitor bank, and a service manual that tells you exactly how to keep it alive.

Overview

Plenty of budget amps of the era quoted a big round figure into 8 ohms and gave up when a real speaker presented a 4-ohm dip. The GFA-5200 is rated at 80 watts into 4 ohms, and that rating is not a marketing courtesy.

The inside is what makes the little Adcom interesting. Adcom used precision-matched MOS-FETs for the gain stage, fed by a custom toroidal transformer and a filter bank totaling 27,000 µF. That is a startling amount of reservoir capacitance for a fifty-watt amplifier. It explains why the GFA-5200 sounds bigger than its rating suggests - those capacitors let it deliver transients and low-frequency weight without the supply sagging.

The measured behavior backs up the design. These are not the numbers of a compromised budget product. They are the numbers of an amplifier that happens to be small.

Distortion this low at the frequency extremes is the hard part, and the GFA-5200 manages it without drama.

Audio (October 1997, p.56) described the GFA-5200 as part of a new line of MOSFET amplifiers built on Adcom's established reputation for performance and value.

Carrying it is easy: the amp comes in under one arm. Audiophile (p.68) noted this approvingly, describing the GFA-5200 as solidly built but scaled down from the usual high-end crate-and-forklift routine. The same review placed it at 50 watts into 8 ohms and 80 into 4, matching the manufacturer's figures exactly. Audiophile (p.70) went further, suggesting that a listener on a budget could put together a CD-only system driven from a Discman's headphone output and still get serious performance from the Adcom.

The GFA-5200 sits in a family alongside the GFA-5300, GFA-5400, and GFA-5500, all of which shared the MOSFET topology that Adcom promoted as the foundation of its line. With efficient speakers or a small room, it is a sensible match. With power-hungry panels, it is the wrong tool. Fifty watts is fifty watts, and no amount of filter capacitance changes the physics of a difficult load.