We have worked long and hard to ensure that the GFA-555se power amplifier improves upon its original eminent version in key areas, delivering even better performance. Externally, the chassis footprint and front panel design are identical to the original. Internally, all circuitry has been upgraded to meet ETL/ETLc, FCC, LVD and CE/EMC requirements using UL approved FR-4 printed circuit boards. High performance component selections include ultra low ESR electrolytic capacitors. The result of these improvements is lower distortion, better dynamic range, improved damping factor and greater stability and separation of individual instruments on the sound stage.

Adcom GFA-555se Stereo Power Amplifier

A legend — refined for a new generation.

The Adcom GFA-555se carries forward the legacy of one of the most iconic amplifiers in hi-fi history, reengineered for greater transparency, control, and musical refinement. Designed to deliver effortless power with precision, it brings a sense of scale and authority that transforms any listening experience.

Producing 200 watts per channel into 8 ohms and 300 watts into 4 ohms, the GFA-555se offers substantial headroom and the ability to drive even the most demanding speakers with confidence. Its high-current design ensures stability and control, maintaining clarity and composure across the entire frequency range.

What sets the 555se apart is its balance of strength and subtlety. Bass is deep and commanding, the midrange is open and expressive, and the highs extend with a smooth, natural ease. The result is a presentation that feels both powerful and refined — capable of revealing detail without ever sounding forced.

With upgraded internal components, balanced XLR inputs, and a modernized circuit design, the GFA-555se builds on its heritage while elevating performance to meet contemporary high-fidelity expectations.

Key Features

• 200W per channel (8 ohms) / 300W per channel (4 ohms) — authoritative headroom for any speaker
• Bridgeable to 600W mono (8 ohms) — maximum power for single-channel or subwoofer applications
• Damping factor ≥900 (20Hz–20kHz) — exceptional speaker control and bass precision
• Balanced (XLR) and unbalanced (RCA) inputs — flexible integration with any preamplifier
• Ultra-wide power bandwidth — 1.7Hz to 100kHz (−3dB)
• Dual voltage compatible — 120VAC & 230VAC / 50–60Hz for worldwide use
• Upgraded internals — modernized circuit design with enhanced clarity and refinement
• Robust build quality — classic Adcom reliability, built to last

Technical Specifications

Specification	Value
Output Power – 8 Ohms (Stereo)	200W per channel
Output Power – 4 Ohms (Stereo)	300W per channel
Bridged Mono Power – 8 Ohms	600W
Frequency Response	10Hz – 20kHz, +0 / −0.25dB (1W into 8 ohms)
Power Bandwidth (−3dB)	1.7Hz – 100kHz
Input Impedance – Unbalanced (RCA)	100k ohms
Input Impedance – Balanced (XLR)	10k ohms
Input Sensitivity	1.75V rms (200W into 8 ohms) / 130mV rms (1W into 8 ohms)
Damping Factor	≥900 (20Hz – 20kHz)
Power	120VAC & 230VAC / 50–60Hz
Maximum Dimensions (H × W × D)	7½' × 12½' × 17' (191 × 318 × 432 mm)
Weight	36 lbs. (16.3 kg)
Shipping Weight	39 lbs. (18 kg)