GFA-7705 & GFA-7707 S.A.F.E.
GFA-7705/07 Features • Precision-matched devices used throughout the signal path. • Independent power supplies for each channel. • Fewer gain stages improve signal reproduction accuracy. • Custom toroidal power transformer provides better regulation and greater peak current capability. • ADCOM-Universal pre-prepped chassis and internal power supplies for easy in-field upgradeability from 5 to 7 channel configuration. • Independent thermal-overload and distortion LEDs for all 5 (to 7) channels. • S.A.F.E.
Introduction Congratulations on your decision to purchase the GFA-7705/07 multi-channel power amplifier. The GFA-7705/ 07 integrates very well with any other home theater system, such as Dolby ProLogic™ or Dolby Digital™. You have made a wise choice that will reward you with exceptionally accurate and musical sound reproduction for years to come.
(1b) (2b) (1) (2) (3a) (3b) (4) Rear Panel Inputs (1) The audio inputs for the GFA-7705 and 7707 are through high-quality, gold-plated RCA jacks to minimize highfrequency losses, noise, etc. They will accept standard RCA-type plugs, one for each of the five channels; Front L (Left), Center, Front R (Right), Surround L (Left), and Surround R (Right). To insure that the performance designed into the GFA-7705/07 is preserved, you should use the highest quality, shielded audio cables possible.
WARNING THERE ARE NO USER-SERVICEABLE PARTS OR FUSES INSIDE THE GFA-7705/07. In the event that the amplifier’s rear-panel circuit breaker fails to reset (opens again when power applied to unit and unit turned on) you must refer the amplifier to ADCOM Factory Service or ADCOM Authorized Service Center. Do not open the amplifier nor remove the topcover—Hazardous and Potentially Lethal Voltage Present and Warranty may be voided.
(5) (6) (7) (8a, 8b) Front Panel On/Off Switch (5) The On/Off Switch controls power to the power transformer and circuits of the GFA-7705/07. Whenever the GFA-7705/07 is energized the Power LED (7) will glow. To turn the GFA-7705/07 on, press the push-button. It will remain in the “engaged” position while the unit is energized. To turn the GFA-7705/07 off, press the push-button in and release and it will move to the “disengaged” position.
Distortion Alert LEDs (7) The Distortion Alert circuit is a unique ADCOM distortion detection system which reads all forms of nonlinear distortion such as THD, IM, slew-induced, “clipping,” etc. The Distortion Alert LEDs will light when distortion reaches approximately 1% regardless of impedance, voltage/current phase angle or the reactance of the loudspeakers which the amplifier is driving.
WARNING Whenever connections to or from the GFA-7705/07 are being made, be certain that the AC On/Off Switch (5) of the amplifier is in the OFF position, the AC Power Cord (4) of the amplifier is disconnected from the AC wall outlet and that all associated components are turned off.
right surround speaker left surround speaker Connecting the GFA-7705/07 Remember, that the Left and Right designations are as you are sitting down in your listening/viewing area. On the rear panel, the inputs and outputs are grouped in 5 or 7 bracketed sets, one set for each channel.
Inputs (1) To preserve the correct effects, 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............................................................ Left Front Red ........................................................... Right Front Green.............................................................. Center White with Blue Stripe .................................
It is suggested that the three front 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 Generally, for the two rear surround channels, longer runs of cable are needed, but since less program material is being transmitted through the cable, longer runs are acceptable: up to 48 feet......................................
Troubleshooting Resolving Problems Use the chart below to solve common situations that don’t require professional attention. If the steps stated in POSSIBLE SOLUTION do not resolve your problem, then please contact your ADCOM Dealer or call the ADCOM Customer Service Department. Any problems not covered here should be brought to the attention of your ADCOM Dealer or ADCOM Customer Service Department.
Servicing ADCOM has a Technical Service Department to answer questions pertinent to the installation and operation of your unit. In the event of difficulty, please contact us for prompt advice. Please have the following information readily at hand: the unit’s model and serial numbers, and dealer from whom it was purchased. If your problem cannot be resolved through our combined efforts, we may refer you to an authorized repair agency, or authorize return of the unit to our factory.
GFA-7700/7707 Specifications Power Rating (To EIA/CEA-490-A Requirements 200 Watts continuous average power per channel into 8 ohms at any frequency between 20Hz and 20kHz with all channels driven at less than 1% THD. 300 Watts continuous average power per channel into 4 ohms at any frequency between 20Hz and 20kHz with all channels driven at less than 1% THD. THD + Noise at 200 Watts into 8 ohms (Typical) 20Hz..................................................................................................
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