Adcom GFA-7400 User Manual

Olnputs:
Be certain to connect the RCA cables to the proper RCA-input connector. If the cables are
color coded, then use this sequence for the connections:
Blue .FL (Front Left)
Red .FR (Front Right)
Green .C (Center)
White with Blue Stripe .LR (Left Rear) / (Surround Left)
White with Red Stripe .RR (Right Rear) / (Surround Right)
©Outputs:
NOTE:
The GFA-7400/7300 is “polarity correct". That is it does not invert phase from input to output.
Any positive signals at its inputs will appear as a positive signal at its outputs
When connecting the amplifier to the loudspeaker, it is vital to maintain proper polarity
(positive to positive, negative to negative). On the GFA-7400/7300, the positive terminal is color
coded RED and labeled “+”, and the negative is color coded BLACK and labeled The positive
terminal on the speaker will be color coded RED, or will be labeled “+”, “pos”, “positive”, “8 ohms”,
or “4 ohms”. The negative terminal on the speaker will be color coded BLACK, or will be labeled “-
”, “neg”, negative”, “C”, “Common”, “G”, or “ground”.
It is recommended that your speaker cables be terminated with “U” type spade connectors.
These will give the most contact area insuring long-term reliability. The spade connector should
have a maximum width of 0.57 inches and 7 ~ (~
an opening width of no less than 0.25” mm0 57 .
(see diagram on right). -J-
_c
■ )
To properly connect the speaker cable to the binding posts, turn the insulated head of the
binding post clockwise until the wire or connector is firmly secured. Finger pressure is sufficient
and you should not use pliers or other tools which could damage or over-tiqhten the binding-post
assembly . The binding posts, have been designed in such a way that finger pressure is all that is
required to cause a "pinching” action among the different metal surfaces to ensure proper
connection.
It is very important to use the correct size of wire in order to avoid unnecessary loss of
amplifier power in the cable, reduction of amplifier damping factor and other undesirable
conditions. Sound audio engineering practice suggests the use of at least AWG16, stranded,
copper cable. Recommended capacitance of the speaker wire should not exceed 50pF per foot.
This insures high frequencies will not be rolled-off.
It is suggested that for all the channels follow this chart for speaker lengths and wire gauges.
up to 24 feet...AWG16
up to 36 feet.AWG14
up to 58 feet.AWG12
If longer runs are needed, it is best to consult with your Adcom Dealer to maximize the
performance of your system with your exact conditions.
7

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)