User manual ADCOM GFA-7400

[. . . ] Because ADCOM amplifiers can output tremendous power, it is particularly important that you connect your amplifier to your pre-amplifier and speakers while the amplifier is unplugged and your other equipment is turned off. This will protect the amplifier and other equipment from potential short circuits from crossed interconnect or speaker wires while you are working on the connections. In addition, it is important that you allow for adequate ventilation around your amplifier and other equipment, since excessive heat buildup can shorten the life of any electronic product, including the amplifier. Once you have correctly connected your pre-amplifier and speakers to your new amplifier, you should be able to enjoy many trouble-free years of performance. [. . . ] Therefore, the GFA-7400/7607 should be kept away from external sources of heat such as radiators and hot-air ducts. The GFA-7400/7607 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-7400/7607. 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-7400/7607, but the free flow of air through the ventilating slots in the amplifier may be partially obstructed. If you observe these recommendations, the GFA-7400/7607 will perform reliably in any reasonable environment. Sound audio engineering practice suggests the use of at least AWG16, stranded, copper cable. Recommended capacitance of the speaker wire should not exceed 5OpF per foot. This insures high frequencies will not be rolled-off. 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. (2) Outputs The GFA-7400'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-7400/7607 for more information). (3) I2V DC Trigger The GFA-7400 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. [. . . ] 0. 075% 1 watt to 175 watts into 4 ohms. 0. 075% IM Distortion (CCIF, Any Combination from 4kHz to 20kHz) 125 watts into 8 ohms. 0. 025% THD + Noise at 125 watts into 8 Ohms (Typical) 20Hz. 0. 02% THD + Noise at 175 watts into 4 Ohms (Typical) 20Hz. [. . . ]