Adcom GFA-7400 User Manual

/Vote t : Cable TV systems can sometimes contribute to ground loop problems which cause
“hum”. To determine if your cable system is the contributing factor, disconnect the Cable-TV
incoming signal line (round, 75Q) at the wall, or the first component the cable is connected to (i.e.
the cable box, or VCR). If the hum is no longer present, you must insert a “750 Ground Loop
Isolator” before reconnecting the line. You should check with your Adcom Dealer to obtain one. If
the “750 Ground Loop Isolator” works only partially or not at all, then please read Note 2 to
complete the troubleshooting procedure.
/Vote 2 : Make sure that the power amplifier is at least 6” from the Preamp and/or Processor.
Usually putting another component between them is sufficient to minimize the hum. If this does
not reduce the hum, turn the system off and disconnect all Inputs from the amplifier. If the hum
still persists, then your Dealer or Service Center must examine the amplifier. If the hum
disappears, try another set of RCA cables. Connect one RCA cable at a time to see if one specific
cable is responsible. If any or all cables cause the hum to appear, then the preamp or processor
should be evaluated for proper operation by your Dealer or Authorized Service Center.
15

Adcom GFA-7400 Specifications

Power

continuous power per channel into 8 ohms	100 watts
continuous power per channel into 4 ohms	150 watts
power consumption quiescent	96 VA
maximum power consumption	1440 VA
power consumption at 100 watts into 8 ohms	1165 VA
power supply voltage	115 VAC - 50/60 Hz

Distortion

IM distortion SMPTE at 8 ohms	≤ 0.075%
IM distortion SMPTE at 4 ohms	≤ 0.075%
IM distortion CCIF at 8 ohms	≤ 0.025%
IM distortion CCIF at 4 ohms	≤ 0.025%
THD + noise at 100 watts into 8 ohms at 20Hz	0.0012%
THD + noise at 100 watts into 8 ohms at 1kHz	0.0012%
THD + noise at 100 watts into 8 ohms at 10kHz	0.02%
THD + noise at 100 watts into 8 ohms at 20kHz	0.025%
THD + noise at 150 watts into 4 ohms at 20Hz	0.025%
THD + noise at 150 watts into 4 ohms at 1kHz	0.025%
THD + noise at 150 watts into 4 ohms at 10kHz	0.035%
THD + noise at 150 watts into 4 ohms at 20kHz	0.045%

Performance

frequency response at 1 watt into 8 ohms	+0, -0.25 dB
power bandwidth	1.5 Hz to 65 kHz
dynamic headroom into 4 ohms	2.5 dB
signal to noise ratio	≥ 110 dB
gain	29 dB
input sensitivity for 1 watt	0.1 volts
input sensitivity for 100 watts	1.0 volts
input impedance	50 kΩ
damping factor	≥ 400
rise time	4.5 µS

Weight and Dimensions

chassis dimensions	5” (127mm) x 17” (432mm) x 14” (355.6mm)
maximum dimensions	5 3/4” (146mm) x 17” (432mm) x 15” (381mm)
weight	42 lb. (19.1 kg)
packed weight	48 lb. (22.8 kg)