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The Adcom GTP 350, GFA 5503, and GDS 6 speaker selector is a very nice set of vintage audio equipment. This amplifier has been recapped / All three power boards.The Adcom GFA-5503 is a highly regarded 3-channel audiophile power amplifier, famous for utilizing MOSFET output stages to deliver tube-like warmth and smoothness. It provides high-current, dynamic power perfectly suited for demanding home theater front stages or active bi-amping. Core Specifications Power Output: 200 W per channel into 8 ohms; 350 W per channel into 4 ohms Channels: 3 fully independent channels, each with its own power supply Circuitry: Precision-matched MOSFET devices throughout the signal path Capacitance: 120,000μF of power-supply filter capacitance for massive reserve capacity Transformer: Custom toroidal power transformer for high peak-current capability Weight & Dimensions: 57 lbs (25.8 kg); 7" × 17" × 16"The Adcom GTP-350 is a solid-state stereo AM/FM tuner and preamplifier released by Adcom. It features a low-profile design, a frequency response of 20Hz to 20kHz (or up to 90kHz depending on measurement), and total harmonic distortion of 0.0075%.The Adcom GDS 6 Speaker Selector is a unit designed for home audio systems. With 5 inputs and 2 channels, this black amplifier from the 1990s features analog technology and RCA audio outputs. The GFA 5503-GTP 350-GFS 6 speaker selector by ADCOM offers a comprehensive solution for those looking to enhance their TV, video, and home audio experience. Built with quality components and a sleek design, this unit is perfect for connecting various audio sources and amplifying sound for a more immersive listening experience. Usual age related scratches and dings.
This is a seller’s market, and at US$1,400 this sits a bit above the current used norm for the model, which centers around US$1,300 with the usual range running from US$1,249 to US$1,350. That makes it a touch ambitious rather than wildly out of line, so I’d call it “worth negotiating,” not an automatic pass.
The GFA-5503 is well liked for serious multichannel muscle, solid current delivery, and a no-nonsense build that still earns respect from people who want real amplification in a home theater or mixed-system setup. If the unit is clean, unmodified, and comes from careful ownership, the appeal is obvious; just make sure the channels are quiet, all inputs work, and it has been serviced if the seller can document it, since age is the main variable here.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
ADCOM emerged in the 1970s as a family-owned American audio venture founded by audiophile Newt Channin, initially focusing on exceptionally musical moving-coil phono cartridges that set it apart from typical entrants. The brand quickly pivoted to electronics with the groundbreaking GFA-1 power amplifier in 1979, delivering 200 watts per channel and robust current for demanding speakers, propelling ADCOM into prominence during the high-fidelity boom of the 1980s and 1990s.
The company built its legacy on high-performance amplifiers, including the Nelson Pass-designed GFA-555 that garnered worldwide acclaim, alongside AV tuners, preamps, and multichannel power amps like the GFA-6000 tailored for home theater. While early roots lay in phono gear, ADCOM specialized in electronics offering superior sound quality without extravagant pricing, eschewing speakers, headphones, or extensive cabling lines.
Positioned firmly in the mid-fi realm, ADCOM defined accessible high-end audio for discerning buyers, blending value and performance that rivaled pricier competitors. After challenges and ownership shifts—including a Thai firm and a faltering 2010 relaunch—the brand staged a robust comeback in 2024 under J&B Distribution, reviving classics like the GFA-555ms alongside modern integrated amps and preamps, reclaiming its spot among savvy audiophiles seeking reliable, soul-stirring sound.
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