https://www.kenrockwell.com/audio/adcom/gfa-555-ii.htm
ADCOM GFA-555 II.
Inputs
100k Ω.
Two gold-plated, Teflon-insulted brass RCA jacks.
They are close enough together to make connection a breeze.
Gain
27 dB.
Input Sensitivity
1.75V for 200 W into 8 Ω.
130 mV for 1 W into 8 Ω.
Rated Power Output
200 watts per channel into 8 Ω from 20 - 20,000 Hz at less than 0.04% THD, both channels driven.
325 watts per channel into 4 Ω from 20 - 20,000 Hz at less than 0.04% THD, both channels driven (requires fan option to do this for any length of time).
600 watts into 8 Ω from 20 - 20,000 Hz at less than 0.04% THD, bridged mono (requires fan option to do this for any length of time).
850 watts into 4 Ω from 20 - 20,000 Hz at less than 0.09% THD, bridged mono (requires fan option to do this for any length of time).
Dynamic Headroom
2.5 dB at 4 Ω.
Power Bandwidth
1.7 - 100,000 Hz at - 3 dB.
Frequency Response
10 - 20,000 Hz +0, -0.25 dB at 1 W RMS into 8 Ω.
Damping Factor
Not less than 800 from 20 - 20,000 Hz into 8 Ω.
Noise
Not less than -110dB down from 200 watts into 8 Ω, A-weighted.
Power Input
120 VAC 50-60 Hz.
72 VA idle.
1,500 VA maximum.
675 VA at 200 W into 8 Ω.
I measure 37.5 watts at idle, cold.
60 watts at idle, warm (0.73A).
92 Watts (1.09A) when delivering 1 watt per channel into 8 Ω.
845 watts when delivering 265 watts per channel into 8 Ω.
It draws
zero power when turned off because it has a real power switch. It's not like modern equipment that never really turns off and consumes power and remains a fire hazard any time its plugged in. The GFA-555 II is completely disconnected when switched off.
Size
Chassis: 6-3/4 x 17 x 12-3/16 inches (172 x 432 x 310 mm) HWD.
Overall: 7-1/4 x 17 x 12-3/16 inches (185 x 432 x 310 mm) HWD.
Weight
35 pounds (16 kg).
39 pounds (18 kg), packed.
Quality
Made in USA.
Replaced by
Replaced by the GFA-5500 in 1995.
