automatically and normal operation will resume. If you are to avoid tripping the thermostat in the transformer continually, you must reduce the sound level demands, correct the load impedance of the loudspeakers, or both.

(8) Thermal Protection LEDs

The GFA-7805/7807 are provided with a thermal protection circuit which will shut down the individual amplifiers

if its heatsink temperature reaches 85°C. The Thermal Protection LEDs will light whenever the thermal protection circuit in its respective channel has been triggered and the amplifier is inoperative. The thermal protection circuitry will typically be triggered by very high power demands into impedances much lower than the amplifier is capable of driving at those levels. If any amplifier channel’s output through the loudspeaker(s) ceases abruptly, and its Thermal Protection LED glows, you will know that its heatsink temperature has become unacceptably high

and the circuitry is protecting the amplification devices. Please note that the Power LED (7) will remain on and the amplifier will still be energized. Once the temperature of the heatsink(s) drops to a safe operating level, that amplifier will automatically resume operation.

Activation of the Thermal Protection circuitry in any of the amplifiers in the GFA-7805/7807 is an indication that the amplifier has been over-driven or that the load the loudspeakers are presenting to the amplifier is unreasonably low. If you wish to prevent recurrent activation of the thermal protection circuitry, you must reduce the volume-level demands or correct the load impedance condition which may be causing activation of this circuitry.

(9) Distortion Alert LEDs

The Distortion Alert circuit is a unique ADCOM distortion detection system which reads all forms of non-linear 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. Sometimes, when the amplifier is in use, the LEDs may occasionally flicker during high volume listening, particularly if you are driving low impedances. This flickering is no cause for concern. The LEDs are simply warning you that the amplifier is approaching its maximum power output into the particular loudspeakers you are using. If, however, the Distortion Alert LEDs glow brightly or are illuminated most of the time during playback, you are over driving the amplifier and should turn down your volume control to reduce

the listening level, otherwise it may cause the Thermal Protection to be activated or, in extreme cases, damage your loudspeakers.

9

Page 8 Page 10
Page 9
Image 9
Adcom GFA7807 owner manual Thermal Protection LEDs, Distortion Alert LEDs
Page 8 Page 10

GFA7807 specifications

The Adcom GFA-7807 is a high-performance power amplifier known for its exceptional sound quality and engineering. As part of Adcom's renowned lineup of audio equipment, the GFA-7807 is celebrated for its ability to deliver powerful and accurate audio reproduction, appealing to audiophiles and casual listeners alike.

One of the standout features of the GFA-7807 is its impressive power output. It provides 200 watts per channel at 8 ohms and can deliver up to 350 watts per channel at 4 ohms. This robust power handling allows it to drive even the most demanding speakers with ease, ensuring that the music remains dynamic and detailed, regardless of the volume level. This amplifier's ability to maintain its performance under high loads is a crucial attribute for high-end audio setups.

The GFA-7807 employs a Class AB amplification design, which balances the benefits of both Class A and Class B amplifiers. This design helps minimize distortion and crossover issues, ensuring that the output remains clean and precise, particularly in the midrange frequencies. The amplifier's low total harmonic distortion (THD) rating further enhances its audio fidelity, making it an excellent choice for critical listening.

In terms of build quality, the Adcom GFA-7807 is constructed with rugged components designed to withstand the rigors of prolonged use. The sturdy chassis and high-quality connectors contribute to its durability, while also minimizing interference and maintaining signal integrity. The amplifier is also equipped with extensive protection circuits, which guard against short circuits, thermal overload, and other potential damage conditions.

Another noteworthy characteristic of the GFA-7807 is its versatility. It features multiple input options, including balanced XLR and unbalanced RCA connectors, allowing for seamless integration into various audio systems. Additionally, its rack-mountable design makes it an ideal choice for professional setups and home theaters alike.

Overall, the Adcom GFA-7807 power amplifier stands out in the audio landscape due to its impressive power handling, low distortion, rugged construction, and versatility. Whether used in a high-fidelity music system or a home theater, it delivers a remarkable listening experience that captures the essence of the original recording, making it a must-consider option for enthusiasts looking to elevate their audio setups.
Top Page Image Contents