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

Set-up
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.


 

 
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