Adcom GFA-7400 User Manual

INSTALLATION & HOOKUP
UNPACKING THE GFA-7500 and GFA-7300
Before your new ADCOM amplifier left our factory, it was carefully inspected for physical
imperfections and tested for all electrical parameters as a routine part of ADCOM s systematic
quality control. This, along with full operational and mechanical testing, should ensure a product
flawless in both appearance and performance. After you have unpacked the GFA-7400/7300,
inspect it for physical damage. Save the shipping carton and all packing material as they are
intended to reduce the possibility of transportation damage, should the amplifier ever need to be
shipped again. In the unlikely event damage has occurred, notify your dealer immediately and
request the name of the carrier so a written claim to cover shipping damages can be initiated.
THE RIGHT TO A CLAIM AGAINST A PUBLIC CARRIER CAN BE FORFEITED IF THE
CARRIER IS NOT NOTIFIED PROMPTLY IN WRITING AND IF THE SHIPPING CARTON AND
PACKING MATERIALS ARE NOT AVAILABLE FOR INSPECTION BY THE CARRIER. SAVE
ALL PACKING MATERIALS UNTIL THE CLAIM HAS BEEN SETTLED.
PLACING THE GFA-7400/7300
During normal home operation the internal heatsinks of the GFA-7400/7300 may become
warm. However, there are instances during high-level playback into low impedances when the
heatsinks will become much warmer than usual. To ensure the amplifier’s long-term, trouble-free
operation it is necessary to provide adequate ventilation for the heatsinks. Therefore, the GFA-
7400/7300 should be kept away from external sources of heat such as radiators and hot-air
ducts. The GFA-7400/7300 should never be placed with other heat-producing components
in a cabinet or enclosure lacking free air flow. The top and bottom panel of the amplifier’s
chassis have been provided with vents to allow the necessary cooling of the internal components.
It is imperative that these vents are not obstructed in any way.
We recommend that you do not stack other components on top of the GFA-7400/7300.
This is particularly important if your system includes low-impedance loudspeakers which are
difficult to drive, or if you will consistently demand high volume levels from the amplifier and
speaker system. Not only will heat generated by the amplifier affect the performance of
equipment stacked on top of the GFA-7400/7300, but the free flow of air through the ventilating
slots in the amplifier may be partially obstructed.
If you observe these recommendations, the GFA-7400/7300 will perform reliably in any
reasonable environment. You should also pay attention to such normal considerations as
protection from excessive dust and moisture. Occasional vacuuming of accumulated dust on the
chassis, panels and around the ventilating slots should be all that is required.
The optimal performance of your new GFA-7400/7300 will ultimately depend on the care
with which you make the connections between the amplifier, preamplifier, surround sound
decoder and the loudspeakers. All input and output signal connections should be made only with
high quality, low-loss, low capacitance cables following the recommendations in the Inputs and
Outputs section of CONNECTING THE GFA-7400/7300.
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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)