Adcom GFA-555se Stereo Power Amplifier

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Adcom GFA-555se Stereo Power Amplifier at Vinyl Sound Buffalo NY

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. Producing 200 watts per channel into 8 ohms and 300 watts per channel into 4 ohms, it offers substantial headroom and the ability to drive even the most demanding speakers with confidence. Available at Vinyl Sound in Buffalo, NY.

Adcom GFA-555se Stereo Power Amplifier — Vinyl Sound Buffalo NY

A Nelson Pass Legacy

The GFA-555se represents the pinnacle of Adcom's audio engineering heritage. The original GFA-555 was a Nelson Pass design that broke new ground when it was introduced in the 1980s, earning rave reviews and a reputation for tank-like reliability at an accessible price. The enduring demand for these amplifiers decades later is a strong testament to their fundamental engineering quality and musical capability. The GFA-555se honors that legacy while elevating every aspect of its performance for a new generation of listeners.

Adcom GFA-555se amplifier heritage — Vinyl Sound Buffalo NY

Upgraded Internals and Better Sound Delivery

Adcom worked to ensure the GFA-555se improves upon its original version in every key area. Externally, the chassis footprint and front panel design remain true 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 throughout. The result is lower distortion, better dynamic range, an improved damping factor of 900 or greater, and greater stability and separation of individual instruments across the soundstage.

Adcom GFA-555se internal circuitry and upgrades — Vinyl Sound Buffalo NY Adcom GFA-555se power amplifier detail — Vinyl Sound Buffalo NY

Key Features

  • 200W per channel into 8 ohms / 300W per channel into 4 ohms for authoritative headroom with any speaker
  • Bridgeable to 600W mono into 8 ohms for maximum power in single-channel or subwoofer applications
  • Damping factor of 900 or greater (20Hz to 20kHz) for exceptional speaker control and bass precision
  • Ultra-wide power bandwidth from 1.7Hz to 100kHz (-3dB)
  • Balanced XLR and unbalanced RCA inputs for flexible integration with any preamplifier
  • Input impedance of 100k ohms (RCA) and 10k ohms (XLR) for compatibility with any source component
  • Ultra-low ESR electrolytic capacitors and UL-approved FR-4 PCBs for reduced distortion and improved dynamic range
  • ETL/ETLc, FCC, LVD and CE/EMC certified to international safety and compliance standards
  • Dual voltage compatible at 120VAC and 230VAC / 50-60Hz for worldwide use
  • Classic Adcom chassis design faithful to the original GFA-555, built for decades of reliable service

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 to 20kHz, +0 / -0.25dB (1W into 8 ohms)
Power Bandwidth (-3dB) 1.7Hz to 100kHz
Input Impedance — Unbalanced (RCA) 100,000 ohms
Input Impedance — Balanced (XLR) 10,000 ohms
Input Sensitivity 1.75V rms (200W into 8 ohms); 130mV rms (1W into 8 ohms)
Damping Factor 900 or greater (20Hz to 20kHz)
Power Supply 120VAC and 230VAC / 50-60Hz
Maximum Dimensions (H x W x D) 7-1/2" x 12-1/2" x 17" (191 x 318 x 432 mm)
Weight 36 lbs. (16.3 kg)
Shipping Weight 39 lbs. (18 kg)

Frequently Asked Questions

What is the Adcom GFA-555se?

The Adcom GFA-555se is a stereo power amplifier rated at 200 watts per channel into 8 ohms and 300 watts per channel into 4 ohms, bridgeable to 600 watts mono into 8 ohms. It is a modernized version of the original GFA-555, designed by Nelson Pass, featuring upgraded internal circuitry, ultra-low ESR electrolytic capacitors, balanced XLR inputs, and a damping factor of 900 or greater. Available at Vinyl Sound in Buffalo, NY.

What is the connection between the GFA-555se and the original GFA-555?

The original Adcom GFA-555 was designed by Nelson Pass and introduced in the 1980s, where it earned widespread critical acclaim and a reputation for exceptional value and long-term reliability. The GFA-555se is a direct evolution of that design, retaining the same chassis footprint and front panel proportions while upgrading all internal circuitry to current standards.

What improvements does the "se" designation represent?

The "se" designation marks a comprehensive internal upgrade. All circuitry has been redesigned to meet ETL/ETLc, FCC, LVD, and CE/EMC certification requirements using UL-approved FR-4 printed circuit boards. Ultra-low ESR electrolytic capacitors are used throughout, improving transient response and reducing distortion. The damping factor has been increased to 900 or greater.

What is the power output and can the GFA-555se be bridged?

The GFA-555se delivers 200 watts per channel into 8 ohms and 300 watts per channel into 4 ohms in stereo mode. In bridged mono mode it produces 600 watts into 8 ohms, useful for driving a single high-power loudspeaker, a passive subwoofer, or any application requiring the amplifier's full output capability in a single channel.

What is the damping factor of 900 and why does it matter?

The GFA-555se achieves a damping factor of 900 or greater from 20Hz to 20kHz. A high damping factor means the amplifier can resist and control unwanted cone movement in the loudspeaker after a transient signal, translating to tighter, more controlled bass reproduction with minimal overhang or bloom.

Where can I buy the Adcom GFA-555se in the USA?

The Adcom GFA-555se is available at Vinyl Sound, an authorized Adcom dealer in Buffalo, NY. Browse the full power amplifier collection at Vinyl Sound or contact our team for system matching advice and in-store listening appointments.

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