DESCRIPTION OF UNIT: REAR PANEL
(1) Inputs
The GFA-7805 and GFA 7807 have both balanced and unbal- anced inputs for each channel. The unbalanced connection is made via the gold plated RCA jack and the balanced con- nection is made via the XLR input connection. Each channel also has a switch which selects the type of input for each channel. Make sure the switch is in the appropriate posi- tion for the type of connection you have choosen. For best performance, always use high quality interconnects. Your ADCOM dealer can help select the best cable for your needs.
(2) Outputs
The GFA-7805’s and GFA-7807’s connections to the loudspeakers are made through high-grade, 5-way, gold-plated binding post terminals. There are two terminals for each speaker, which are colored RED for the positive (+) output and BLACK for the negative (-) output.
The binding posts will accept a variety of connector types. The most secure and prevalent of these is the “U”-type spade connectors (at least 0.25’’ wide and maximum width of 0.57”). The terminal will also accept bare wire (up to AWG1O) and “banana” type plugs (single or dual).
(3) I2V DC Trigger
The GFA-7805 and GFA-7807 are very high power amplifiers and as such must be directly connected to the wall outlet or an appropriate surge protector or AC line conditioner.
It must never be connected to the ‘switched’ outlets on the rear panel of a pre-amplifier. Usually this would mean that when you turn on/off your pre-amplifier you would have to turn on/off your power amplifier separately. We have, however, provided the ability to control the OFF/ON function of the GFA-7805/7807 by a l2V DC output jack on the rear of certain ADCOM pre-amplifiers. When using this feature the front panel Power Switch must be left in the in “on” position. To connect the preamplifier 12V DC output jack to the amplifier 12V DC jack, you will need a monaural mini phone plug to monaural mini phone plug cable. Contact your dealer for information on using this feature with ADCOM and other brand pre-amplifiers.
(4) AC Fuse
The AC Fuse protects the electronic circuits of the GFA- 7805/7807. This fuse, normally, will fail only if there
is an overload within the GFA-7805/7807. If your fuse fails please contact your dealer or ADCOM directly for a replacement or servicing.
(5) AC Power Cord
The AC cord provides power to operate all the GFA- 7805/7807’s circuits. Its plug can be connected to a standard wall outlet provided the outlet supplies a voltage compatible with the power requirements printed on the rear panel of the GFA-7805/7807.
DESCRIPTION OF UNIT: FRONT PANEL
(6) On/Off Switch
The On/Off Switch controls power to the power transformer and circuits of the GFA-7805/7807. Whenever the GFA-7805/7807 is energized the Power LED (7)
will glow. To turn the GFA-7805/7807 on, press the push-button. It will remain in the “engaged” position while the unit is energized. To turn the GFA-7805/7807 off, press the push-button in and release and it will move to the “disengaged” position.
(7) Power LED
This LED will glow whenever the On/Off Switch (6) is turned on and the GFA-7805/7807 is energized. The Power LED indicates that there is AC voltage being fed to the amplifier, but it does not signify that all the amplifier’s circuits are in operation. If, for example, one of the Thermal Protection LEDs (9) glows, that amplifier channel will not produce sound even though the Power LED may still glow. When the GFA-7805/7807 is turned off, the Power LED will take some time to fade out completely. It may take up to 30 seconds to fully extinguish. Additionally, the internal power transformer is provided with a thermostat which will interrupt power into the transformer if its temperature exceeds 125°C. This high temperature will seldom, if ever, be encountered unless the amplifier is subjected to abnormal conditions, such as operation into loads of less than 3 ohms at very high listening levels, etc. If the AC Fuse (4) has not failed, the Power LED is out, and the Thermal Protection LED (9) does not glow, this would indicate that the thermostat within the transformer has opened.
Once the temperature within the transformer decreases to a normal level, the thermostat will reset itself
