Adcom GFA-555se specs

To set the ampliﬁer in bridged mono operation, ﬂip the STEREO/BRIDGED input switch into the BRIDGED position. When in the bridged mono mode, input to the ampliﬁer is made only through the LEFT input jack. The connection to the RIGHT input jack should be removed since the right-channel input portion of the ampliﬁer is inoperative.

Only a single loudspeaker is to be connected to the GFA-555se when in the bridged mono mode. Please note that connections made to the loudspeaker from the GFA-555se, when used in the bridged mono mode, are different from those made when the ampliﬁer is used in the stereo mode. The LEFT RED output binding-post terminal (labeled BRIDGED MONO OUTPUT “+”) should be connected to the loudspeaker input terminal color-coded RED (or labeled POSITIVE, “+”, POS, 8 OHMS or 4 OHMS). The RIGHT RED output binding post terminal on the ampliﬁer (labeled BRIDGED MONO OUTPUT “-”) should be connected to the BLACK loudspeaker terminal (or labeled NEG, “-”, C, COM, COMMON, G, or GROUND). Please note that if you want to insure correct stereo phasing with optimal bass response, you must observe these connections precisely.

Although the GFA-555se can generate a substantially greater amount of power in the bridged mono mode than when it is in its normal stereo mode, it requires the use of loudspeakers whose nominal impedance does not drop below 4 ohms. It is not recommended that the GFA-555se be used in the bridged mono mode into loudspeakers, or multiple loudspeaker loads, which drop in value substantially below 4 ohms. Otherwise, you may trigger the THERMAL PROTECTION or blow one of the DC RAIL FUSES. A little known fact is that when any ampliﬁer is operated in the bridged mode, the load is “split” between the two ampliﬁers in the bridged conﬁguration. Therefore, an 8-ohm loudspeaker will be seen by the ampliﬁer as if it were a 4-ohm load; a 4-ohm loudspeaker load will be seen by the ampliﬁer as a 2-ohm load.

NOTES:

a)If the connections described above are followed exactly, the GFA-555se will be polarity correct, that is, it will not invert “phase”. Any positive-going signal at its input will appear as a positive-going signal at the loudspeaker.

b)For use in professional installations, the GFA-555se may be mounted in a standard 19-inch rack using the optional RM-7 rack-mount adaptors available through ADCOM dealers. If the GFA-555se is to be mounted on a rack, along with other components which are interconnected to the GFA-555se, the ampliﬁer’s chassis must be insulated from the metal-rack rails to prevent ground loops, especially if the rack is grounded to “earth”, and to avoid defeating the audio grounding scheme of the power ampliﬁer (the audio-input grounds are isolated from and above the chassis ground). Please consult the instruction sheet packed with the optional rack-mount adaptors for more information.

c)The DC RAIL FUSES provide protection for the output stages and power supply in the event of excessive current demands from the ampliﬁer, either long-term or short-term. If the ampliﬁer ceases to operate, either on one or both channels, particularly during high-level passages, or long-term high-volume playback, and the POWER LED glows while the THERMAL PROTECTION LED is out, the chances are that one or both of the DC RAIL FUSES on that channel, or both channels, are blown. In the event that the DC RAIL FUSES need to be replaced, refer servicing to qualiﬁed service personel. DO NOT USE ANY SUBSTITUTE FUSES WITH DIFFERENT RATINGS, TIME-CURRENT CURVES OR VALUES. Failure to observe this precaution may cause serious damage to the ampliﬁer circuits, MAY CREATE A FIRE HAZARD, AND MAY VOID YOUR WARRANTY.

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.