Adcom GFA-7805 Multi-channel Power Amplifier 
Home Theater Power Amplifiers Multi-Channel Amplifiers
Written by Bryan Dailey   
Wednesday, 01 June 2005

Adcom has carved an undeniable niche in this industry by manufacturing rock solid high-end electronics at budget prices. In fact, many music enthusiasts with mega-dollar systems fondly recall Adcom as one of their first high-performance audio investments back in the late 1980s. Decades later, Adcom is still providing consumers with quality components at a fraction of the price of many of its higher-end peers. The GFA-7805 is a 300-watt, five-channel amplifier designed to drive your 5.1 home theater or multi-channel music system, retailing for $2,599.

As model numbers go, the GFA-7805 amp from Adcom is one of the easiest to remember. As if it were conceived in bar by a couple of dudes who each had a beer in one hand and darts in the other, GFA simply stands for “Great F’ing Amp.” There’s a model number that will set it apart for an otherwise conservative industry.

The GFA-7805 tips the scales at 88 pounds and measures nine-and-three-quarters inches tall, 17 inches wide and 20.75 inches deep. Rack-mounting it should be no problem, as long as you keep it low in your rack, make sure it’s ventilated and have a shelf that is strong enough to hold the weight of this bad boy. There are certainly heavier amplifiers out there, but unlike many 100-plus pound amps, the GFA-7805 does not have any handles for lifting. All of the edges of the amp are very squared off and the front grille has sharp edges, so you will want to have a friend help you move the amp in and out of a rack to keep from scraping yourself. I caught the side of my thigh slightly with the corner when moving it into my rack and it left a pretty good mark on my leg for a few days.

Under the hood, the bulk of the weight comes from massive toroidal transformers. The GFA-7805 features a monoblock power supply design for all five channels and 112,000 micro Farads of power supply capacitance. The GFA-7805 delivers 300 watts x five channels into eight ohms and has a power bandwidth from 10 Hz – 100kHz. This amplifier will drive any speaker on the planet, most to complete excess.

Stylistically, the GFA’s silver and black faceplate is an exact match to all of the current products in their line, including their GTP-880 AV preamp ($2,400) and GDV-850 progressive scan DVD player ($1,000) that I used for this review. The components are all the same width and color, so they make a slick package when lined up in a row or arranged together in a rack.

The back of the GFA-7805 features five sets of balanced XLR inputs, five sets of unbalanced RCA inputs and five gold binding posts. There are not a lot of frills to this amplifier, as the rest of the elements on the outside of the case are only a fuse socket, 12v input trigger and power cord input on the back and the on/off button and a series of LED/status lights on the front. These lights are useful for determining the amount of signal going to each channel. A special light lets you know if the channel is overheated, thus protecting the amp.

There are no external heat sinks on the GFA-7805 and the grooves on the front of the amp are designed to help the amp dissipate heat, yet they are very small. They are seemingly more cosmetic than functional as most of the heat dissipates via the internal heat sinks through the vent holes on the top. I have never had the amp shut off on me and it never got overly hot, so heat was not an issue for me. Regardless of my personal experience, you will always want to use the usual precautions, such as allowing ample space around the amp in a rack, not stacking gear directly on it and putting a cooling fan in or around the amp if possible. An overheated amp is an unhappy amp, but I have not experienced any problems in this department in the time that I have had the GFA-7805 in my rack, even when driving the music at ear-scorching levels.

The day this amp arrived, I was not prepared. It was shipped in a wooden crate that was quite large and heavy, so I enlisted a friend to help me bring it up my stairs into my living room. In doing research on the technical specs, I found that Adcom actually gives customers a heads-up by mentioning that the amp ships in a wooden crate and they even go so far as to call it the “fattest” five-channel power amp in their line. My level of anticipation was very high for the rock ‘n’ roll potential of this solidly built and beefy amplifier.

As I pushed the button on the front of the amplifier, I felt a little like the warden manning the electric chair deep inside a dingy prison cell, waiting to unleash untold amounts of voltage on a convicted murderer. As the button clicked, the room went completely black. Pow! I threw a breaker. After a quick trip down to the garage to flip the circuit breaker, I was greeted by another blackout when powering up the amp. It turns out this amp is rated at 20 amps for proper "real power" performance according to Adcom and I was trying to run it on my 15-amp system in my home. Okay, so even the pros are guilty of firing up their gear before completely reading the manual. It looked like the review would have to be delayed, since the only 20-amp service I had in my home was for my dishwasher. I recently moved into a new home and, when it was being built, I made sure that a 20-amp breaker was put in the theater. If you have the choice of what size breakers to have your theater connected to, I’d highly advise going with 20 amps. Many computer manufacturers also recommend running their machines on 20 amp service, so it would be wise to have some installed if your electrical system will allow it.

The Adcom GTP-880 preamp has 7.1 capabilities, but my room is not set up for a 7.1 system and the GFA-7805 is not, either. If having seven-channel surround is something that is absolutely mandatory for you, Adcom has the solution for you in the GFA-7807, which is essentially a 7805 with an extra two channels of amplification for $3,599.

After working out my circuit issues with the electrician, I plugged in the power cord and, voila, the lights in my home stayed on and the GFA-7805 came to life. It was time to rock.

The Music
To start, I wanted to listen to some surround sound material that I was very familiar with, so I plucked my Grover Washington DVD-Audio disc Winelight (Warner Music) from the shelf and spun it up to hear the difference from my previous set-up, featuring a comparably-priced Anthem power amp. This smoothed out pop/jazz album has studio musicians on it with some impressive chops and features an outstanding surround mix by Elliot Scheiner. It immediately came to life with a power and presence not felt through previous listening sessions. The low end is important in any R&B record and, although my Energy sub was doing some of the work, the newly-found power that the C-5 floor-standing speakers were receiving really brought the recording to life. Washington’s saxophone had new detail and clarity but was not brittle in the high end. It felt as if the amp was perhaps rolling off the high end a tad, but not in a way that hindered the song. The vocals on the hit tune “Just the Two of Us” were equally smooth, without any harshness in the high end and no matter how loud I turned up the amp, I was able to maintain this clarity throughout the song.

Seal’s IV album is another surround sound mix that really thumps on the low end but has delicate instrumentation. On the single “Get It Together,” the dance groove is a workout for any speaker/amp combo and the GFA-7805 held it all together with ease and never flinched at the various changes in the song from the verses to the choruses to the bridge. It was smooth, even and always powerful. Seal’s signature rasp was even and coherent, with much more detail than with other amps I have heard in my system in this price category. Even when turning the amp down, it was still feeding the speakers with ample amounts of power, so it seems like this amp was made to be played loud. I could almost hear the volume knob begging on the Adcom preamp begging to be turned clockwise.

The amount of new albums on DVD-Audio and SACD has rolled off dramatically in the last six months and the new Queens of the Stone Age album Lullabies to Paralyze (Interscope) is not out on DualDisc yet, so I cued up their new two-channel release to hear how the GFA-7805 could hand some really low-end heavy hard rock on CD. Don’t let the fact that QOTSA lead singer Josh Homme looks exactly like former ESPN anchor turned retired late-night talk show host Craig Kilborn. This band who rose out of the ashes of grunge rockers Kyuss is one of the best alterative rock acts going today and their song “Little Sister” is crushing Green Day singles and sensitive John Mayer songs on alternative radio as we speak. A solo guitar riff begins the song and when the full band comes in with the tuned-down, distorted bass tone, I was expecting some of the bottom to drop off the soundstage. Not a chance with the Adcom, as the lights on the front started really lighting up indicating that it was working very hard, but it never gave up the fight and was able to give better than arena rock-type sound in my own living room without harsh boom.

The Movies
To give the amp a chance to test a dialogue-driven film that also features low, power-sucking sound effects, I watched “The Aviator,” Martin Scorsese’s epic tale of the life of Howard Hughes starring Leonardo DiCaprio. This drama is not only an incredible portrait of this eccentric billionaire, it also features many demo-worthy scenes. Airplane flybys are a good test for any surround sound system and the huge reserve of power that the GFA-7805 has under its hood was able to pump out the necessary juice to make it feel like you were literally there with Mr. Hughes as he was watching his newest aircraft going on its maiden voyage.

Jack Black’s brilliant slacker-turned-schoolteacher family comedy “School of Rock” was recently broadcast in HDTV, so I decided to record it on my Dish Network PVR and evaluate a film in which dialogue and soundtrack are equally important. At the end of the film, during the battle of the bands, competition, Jack is on stage with his students and he banters with the crowd on the microphone, introducing the various members of the band. I had seen the film on DVD through my Kenwood set-up and it was sometimes a struggle to hear what he was saying. During the band’s performance, the crowd members scream like maniacs and the vocals can be hard to decipher, but I got to hear lyrics that I hadn’t noticed before, even when watching the film in the theater.

The Downside
The necessary 20-amp service required to run this amp is going to be an issue for many who are not in the process of building a new home. Unless your house was built in the last few years, it likely has 15-amp outlets throughout the house. Retrofitting an existing outlet is no easy task in many cases and calling an electrician will set you back at least a few hundred dollars. I tested the amp on 15-amp outlets at my old and new homes, and in both cases, I popped the breaker, so you need not run your own experiment. If you are unsure of your outlets, you can go to your breaker panel, identify which breaker goes to your outlet and look at the number on the breaker. If it has a 20, you are in luck. Otherwise, you will need to consider the cost of upgrade into your purchase price.

The styling of the GFA-7805 is a little on the sterile side. The silver and black combination with completely square lines tell you that the amp is more about sounding great than looking pretty, as you might expect of an amp costing many times more.

The GFA-7805 provided me with huge reserves of power and performed at a level considerably beyond its price. It’s massive in stature, yet it remained liquid and nimble.

I have had a chance to evaluate a similar set-up, featuring the comparably-priced and much-respected Anthem Statement A5 amplifier. Like the Adcom, this is an outstanding power amp for the price. The Statement A5 is an amp with a little less power (180 watts RMS x five into eight Ohms; 265 watts RMS x five into four Ohms) and is about 30 pounds lighter. The lighter and smaller Anthem integrated into my cabinet a little easier, but when it came to comparing sound of the two amps, both had punch in the low end. I’d give the slight edge to the Adcom and a virtual tie to them in the midrange. Each has its own flavor. I found the Adcom to be more favorable to music, while the Anthem seemed to produce slightly more detail when watching movies. Both amps make beautiful sound for the money and you’d owe it to yourself to hear both of them if you are the market for a surround sound amplifier.

Adcom’s engineers used the large case of the GFA-7805 to its full potential by packing a lot of horsepower inside. Movie soundtracks and dialogue sound killer on my system now, but surround and two-channel music is what really shines. Despite its cold, hard design lines, this solid-state amp is warm and inviting when listening to music but not so rolled off on the top that the music lacks detail. It ends up making for long, easy listening sessions that don’t become fatiguing on the ears. The GFA-7805 lives up to its acronym. It really is a great f’ing amp for the money.
Manufacturer Adcom
Model GFA-7805 Multi-channel Power Amplifier
Reviewer Bryan Dailey

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