Description of Unit Rear Panel | Adcom GFA-555se manual

DESCRIPTION OF UNIT: REAR PANEL

(1) Inputs (unbalanced)

The audio inputs for the GFA-555se 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 channel; Left and Right. To insure that the performance designed into the amp 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-555se for more information).

(2) Inputs (balanced)

The audio inputs for the GFA-555se are through high-quality, Balanced XLR jacks to minimize high-frequency losses, noise, etc. They will accept standard XLR-type plugs, one for each channel; Left and Right. To insure that the performance designed into the amp is preserved, you should use the highest quality audio cables possible. There are many cables speciﬁcally designed for this application. Your ADCOM dealer can help select the best cable for your needs. (See CONNECTING THE GFA-555se for more information).

(3) Outputs

The GFA-555se 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). (Refer to your User Manual for your speakers for additional information).

(4) AC Fuse

The AC Fuse protects the electronic circuits of the GFA- 555se. This fuse, normally, will fail only if there is an overload within the GFA-555se. 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-555se for 115 volt operation
Fuse Rating	BUSS®	Littelfuse®
12 Amp 250 Volt ... AGC-12/250V .... (3AB) 314012/250V
GFA-555se for 230 volt operation
Fuse Rating	BUSS®	Littelfuse®
6 Amp 250 Volt ....	AGC-6/250V ..... (3AG) 314006/250V

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 (8) does not glow, it may be an indication that the AC fuse has blown. 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 #2 standard Phillips screwdriver. Place the screwdriver in the recessed “crosshead” in the cap. Turn the cap counter-clockwise, until the cap releases 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.

Since the fuse has a ceramic body, you cannot visually examine the fuse element, it is therefore suggested that you replace it with an identical substitute or bring the fuse to your ADCOM dealer so they may check its integrity. To replace the fuse, insert it in the back of the fuse-holder cap. Place the cap into the fuse-holder. Place the screwdriver in the recessed slot, gently press in and turn 1/8-turn clockwise.

(5) AC Power Cord

The AC cord provides power to operate all the GFA-555se’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-555se.

GFA-555se specifications

The Adcom GFA-555se is a high-performance audio power amplifier that stands out for its robust design and exceptional sound quality. Renowned among audiophiles, it offers a blend of remarkable power output and fidelity, making it suitable for a wide range of audio systems.

One of the main features of the GFA-555se is its impressive power output, rated at 200 watts per channel into 8 ohms and 330 watts per channel into 4 ohms. This ample power allows it to drive a variety of speakers efficiently, delivering dynamic and impactful sound reproduction. The amplifier is designed to handle both high and low frequencies with precision, ensuring a balanced audio experience.

In terms of technology, the GFA-555se employs a classic Class AB design, which is known for its ability to combine the efficiency of Class B operation with the linearity of Class A. This results in lower distortion and better thermal management, contributing to a cleaner sound, particularly at high volumes. The amplifier also incorporates a high-speed output stage, which enhances transient response and enables the reproduction of fast-paced musical passages without degradation.

Another notable characteristic of the GFA-555se is its build quality. The chassis is constructed from heavy-duty aluminum, which not only results in durability but also helps to dissipate heat effectively. This is crucial in maintaining performance and longevity, as overheating can lead to shortened component life. Additionally, the amplifier features a massive power supply with a large transformer, providing stable voltage and current to the output stage, which further enhances audio performance.

The GFA-555se is equipped with unbalanced RCA inputs and can be easily integrated into existing audio setups, making it a versatile choice for both home theater and stereo systems. With its impressive parasitic rejection and low noise floor, it ensures that the audio signal remains clean and unaffected by external interference.

In conclusion, the Adcom GFA-555se is a powerful and reliable amplifier that combines advanced technologies with robust construction. Its ability to deliver high-quality sound across a broad range of frequencies, along with its impressive power output and efficient design, makes it a popular choice among music enthusiasts and professionals alike. Whether used as part of a high-end audio system or in a home theater setup, the GFA-555se continues to be a respected component for achieving an immersive listening experience.