Adcom GFA-5802 Stereo Power Amplifier 
Home Theater Power Amplifiers Stereo Amplifiers
Written by Brian Kahn   
Saturday, 01 December 2001

Introduction
The GFA-5802 is Adcom’s most powerful amplifier at 300 watts per channel and, at $1,750, is also their most expensive. This 48-pound giant is cosmetically similar, with Its black matte finish and horizontal grooves, to other Adcom amplifiers of late. The distinguishing aesthetic mark on the GFA-5802, which is shared by other high-end Adcom products, is the small gold plate centered on the lower front of the amplifier. This plate has a toggle switch for the power, flanked by LEDs to indicate thermal overload or high distortion levels.

The amplifier’s finish, while utilitarian, is well done, with no obvious tool marks. The finish features a baked-on matte black enamel, which should hold up well. Both sides of the amplifier feature large heatsinks, which eliminate the need for a cooling fan. The rear panel features balanced and single-ended inputs, as well as a switch to choose between the two. There are two sets of five-way binding posts to ease bi-wiring. Lastly, the rear panel also features a detachable power cord.

The GFA-5802, like Adcom’s highly acclaimed GFA-555, is a Nelson Pass design. Like most Pass designs, this uses minimal circuitry to help obtain a high degree of accuracy. Internally, the heart of the amplifier’s power supply is an extremely large, custom-wound, toroidal power transformer that, coupled with dual secondaries and over 100,000 micro-farads of power supply filter capacitance, ensure plenty of power on tap. There are 16 output devices per channel, which will eliminate any potential of a bottleneck in the power output.

Set-up
I listened to the GFA-5802 mainly in my two-channel system. The amplifier’s 48 pounds is a bit burdensome to keep moving around. If you are going to place the amplifier in a shelving unit or rack, you may want to have a friend over to give you a hand with getting the amp in place. Once the amplifier is in place, the rest of the installation is easy. I used the single ended connections coming out of my Krell 300iL and simply made sure that the "single-ended / balance"’ switch was pointed towards the input used. The binding posts are pretty basic but sturdy, so I had no problems with making any of the connections.

A final note about the setup, make sure the amplifier has plenty of breathing room. The GFA-5802 runs very warm. Adcom is not kidding in their advice to give it plenty of air space.

The Music (Two-Channel)
I own another Adcom amplifier, the three-channel, 200 watt-per-channel GFA-5503, and am very familiar with its sound. As I was hooking up the new GFA-5802, I was very curious as to how the two units would compare.

I let the amplifier break in for a few days before my first serious listening test. Anxious to test the amplifier’s power reserves, I quickly loaded Dire Strait’s Brothers In Arms (WEA/Warner Brothers) and went to the standard "Money For Nothing." This rock 'n' roll classic opens with some explosive guitar and drum work that I played at nearly concert levels. The large power supply and dynamic range of the GFA-5802 enabled me to listen to this track at very loud levels, with no noticeable compression or musical strain whatsoever. This is a description generally reserved for amplifiers in an entirely different category. I dare to compare this under-$2,000 Adcom with amps from Krell and Macintosh costing thousands more.

The GFA-5802 sounds better than I expected it would. The sound is remarkably grain-free and smooth, without the loss of detail that often accompanies "smoothness" at this reasonable price. There is a slight rolloff of the highest frequencies, but this is not noticeable unless you are listened for it and it's never intrusive.

The Adcom’s airy smoothness lends itself to wide-open soundstages, such as on Duke Ellington’s Ellington At Newport 1956 (Sony-Columbia). This album was taped live at the 1956 Newport Jazz Festival and features the whole band, as well as some guest artists. The soundstage was recorded with plenty of room, extending fairly deep and out beyond the far edge of my B&W CM4 speakers. With all of this power on tap, I was a bit concerned that this amplifier might be a brute and steamroll the nuances into oblivion. I closely listened to this album as Paul Gonsalves’ now-famous solo came up between "Diminuendo in Blue" and "Crescendo in Blue," and was relieved to find that I had no reason for worry.

The Adcom also performed well on smaller-scale recordings. Michael Penn’s "No Myth" from the March (BMG) album is an intimate, acoustic track that is very telling when used to examine the imaging characteristics of a system. Both Penn’s vocals and the instrumental backing are portrayed solidly and with a good amount of clarity. Penn’s acoustic guitar sounds solid and realistic and the sonic image is full but not flabby.

The bass on the Adcom is quite powerful and full. The recently reviewed Krell 300iL is slightly quicker on the attack, lending itself to revealing a bit more detail, but both amplifiersare consistent in producing powerful, solid bass. While listening to Crystal Method’s album Vegas (City of Angels), in particular the track "Busy Child," this difference makes itself clear. This track features deep, synthetic bass that is very quick and sharp. The Krell and the Adcom both render the bass with strength and solidity, but the Adcom can't quite keep up with the speed of the Krell.

I then listened to Enya’s Watermark (Reprise) album. This album features large orchestral pieces, with large dynamic transitions as well. The Adcom has no problems with this album at any listening level. The Adcom’s smooth and neutral character compliments this album well. The Adcom is powerful enough to play all of the complex and dynamic pieces without any hint of compression or distortion. This particular album provides a good demonstration of how the GFA-5802 compares sonically with the Krell and McIntosh Laboratories amplifiers recently reviewed here.

The Adcom, the Krell 300iL amplifier section and the McIntosh Laboratories MC602 are all extremely good and have ample power for just about anything short of running the public address system at your local football stadium. The Krell is very sharp and clinical, accurate but slightly cold. On the other side, the McIntosh is still accurate, but not as sharp and its tonal balance yet is warmer, reminiscent of tubes. The Adcom falls between these two, slightly closer to the McIntosh with its laid-back character. The Adcom’s midrange is not quite as warm and "tubey" as the McIntosh, but it definitely leans that way.

The Movies and 5.1 Audio
I also spent some time listening to the GFA-5802 in my theater system. I used the GFA-5802 to drive my main left and right speakers and an Adcom GFA-5503 to drive my center and rear speakers. While comparing the two Adcom amplifiers in my two-channel system, I noted some differences. I was curious to see if these would be evident in a multi-channel setup.

I began with my "Gladiator" (DreamWorks) DVD. While carefully listening to the battle scene in the beginning of the movie, particularly the parts where the catapults were ratcheted back, the sound remains consistent as it moves from speaker to speaker and from amplifier to amplifier.

5.1 music is also well reproduced through the Adcom amplifiers. My 5.1 music listening consisted mainly of Toy Matinee’s self-titled DVD-Audio (DTS), Lyle Lovett’s Joshua Judges Ruth (DTS) and a couple DTS DVD-Audio discs for good measure. The pans remain smooth from speaker to speaker, despite the fact that they are driven by different amplifiers.

During a critical listening comparison between the GFA-5802 and GFA-5503, it was easy to discern the additional refinement of the GFA-5802, but their basic sonic signatures are similar enough to integrate the two amplifiers into a theater system without any detriment.

The Downside
I would have liked to see some additional features on this amplifier, such as a 12v trigger input or an auto-power circuit, as I felt uncomfortable leaving this warm amplifier on all the time. Sonically, I would have liked to see the highs slightly more extended and a quicker response to the leading edge of a note. Neither of these sonic attributes will be noticeable without a direct comparison to an amplifier capable of such feats. One has to be especially careful when seeking extended highs, as they often come with a high price.

Conclusion
The Adcom GFA-5802 is quite a powerhouse and offers tons of audio bang for the buck. The GFA-5802’s neutral, slightly rolled-off characteristics make it a good match for most systems. The amplifier’s sonic shortcomings discussed above are minor and may not be evident in many systems. The Adcom offers a substantial taste of first class, high-power performance at a coach price.
Manufacturer Adcom
Model GFA-5802 Stereo Power Amplifier
Reviewer Brian Kahn





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