DESCRIPTION OF UNIT: REAR PANEL
(1) Inputs
The audio inputs for the GFA-7605 and GFA-7607 are through high-quality, gold-plated RCA jacks to minimize high-frequency losses, noise, etc. They will accept standard RCA-type plugs, one for each of the channels. To insure that the performance designed into the amplifier is preserved, you should use the highest quality audio cables possible. There are many cables which are color-coded and specifically designed for this application. Your ADCOM dealer can help select the best cable for your needs.
(See CONNECTING THE GFA-7605/7607 for more information).
(2) Outputs
The GFA-7605’s and GFA-7607’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).
(See CONNECTING THE GFA-7605/7607 for more information).
(3) I2V DC Trigger
The GFA-7605 and GFA-7607 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-7605/7607 by a l2V DC output jack on the rear of certain ADCOM pre-amplifiers and tuner preamplifiers. When using this feature the front panel Power Switch must be left in the in “on” position. To connect you will need a monaural mini phone plug to monaural mini phone plug cable of appropriate length (not included) to reach from the rear panel of the amplifier to the rear panel of the pre-amplifier. 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- 7605/7607. This fuse, normally, will fail only if there is an overload within the GFA-7605/7607. It may, however, fail if the amplifier attempts to deliver very high power into very low-impedance loudspeakers. In either case, BE SURE TO REPLACE THE AC Fuse ONLY WITH AN EXACT REPLACEMENT FUSE. The proper fuse values are:
GFA-7605 for 120 volt operation — Fuse Rating: 13 Amp
GFA-7605 for 230 volt operation — Fuse Rating: 6.5 Amp
GFA-7607 for 120 volt operation — Fuse Rating: 15 Amp
GFA-7607 for 230 volt operation — Fuse Rating: 8 Amp
Before attempting to replace a failed fuse, be certain to unplug the AC Power Cord from the AC wall outlet to prevent possible electrical shock. Replace the AC Fuse only with one identical in type and rating as printed on the rear panel. DO NOT USE ANY SUBSTITUTE FUSES WITH DIFFERENT RATINGS OR VALUES. Failure to observe this precaution may cause serious damage to the amplifier circuits, may create a hazard fire, and may void the warranty. If the Power LED (7) does not glow, it may be an indication that the AC fuse has blown. If you are using the 12V
DC Triggering feature it may be possible that there is a problem with that connection. To determine if the problem is caused by a malfunction in the 12V DC system, remove the small plug inserted into the I2V DC Triggering jack. Press the front panel power switch to turn off the amp, and immediately re-press the power switch. If the problem is caused by the 12V DC triggering circuit the amp will turn on and the LED will glow. DO NOT attempt repair of the 12V DC system. If you are not sure, or the amplifier displays other symptoms, please consult the RESOLVING PROBLEMS section on page 12.
Fuse replacement
To remove the fuse-holder cap, you will need a 1/4” standard flat-blade screwdriver. Place the screwdriver in the recessed slot in the cap. Turn the cap 1/8-turn counter-clockwise, until the cap pops out towards you. Grasp the cap with your fingers and pull it completely out. The fuse is inserted in the back of the cap; gently pull it free.