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Product Review
 

Outlaw Audio 770 Seven-Channel Power Amplifier

November, 2002

Rick Schmidt

 

 

 

Specifications:

Power output: 200 watts RMS x 7 (all channels driven simultaneously into 8 ohms from 20 Hz to 20 kHz with less than 0.05% total harmonic distortion). 300 watts RMS x 7 @ 4 ohms
S/N: 119 dB
Power Bandwidth:5 Hz - over 100 kHz (+0/-3 dB)
Damping factor: 850 (10 Hz - 400 Hz)
Input sensitivity/Impedance: 1.43 volts for full output/28 k ohms
Crosstalk: Greater than -90 dB from 20 Hz to 20 KHz
Gain: Voltage gain of 28 dB
Slew rate: 50 Volts/microsecond
Remote Trigger voltage: 3 - 32 volts DC
Power requirements: 115 V 50-60 Hz
Power consumption: 1,800 watts (maximum)
Dimensions 7 3/4" H x 17 1/4" W x 18" D
Weight: 90 Pounds
MSRP $1,799 USA
 

Outlaw Audio

http://www.outlawaudio.com

 

Introduction

I have been a reluctant convert to home theater. My preference has been to put any extra money into my two channel system. The driving force in a movie is plot, not sound quality, at least that is what my opinion used to be.

Nonetheless, my unnatural attraction to these rectangular boxes that aid in the production of sounds eventually led me to assemble a sound system to accompany my RPTV. I have discovered that assembling and tweaking any sound system, no matter the number of amplification channels, is my idea of a good time. As I said, it’s an unnatural attraction.

Asked to review the Outlaw 770 seven channel amp, my first thought was that I don’t have seven channels worth of speakers. Then I realized that I do. They were not all manufactured by the same company or even in the same decade, but since (as I have noticed) not a whole lot is going on in the rear speakers most of the time I said, "Sure."

Along the way I discovered that there is no such thing as too many amplifier channels. Well, there may be, but even with the seven channel 770, I still don’t have quite enough. More on that later.

There have to be some tradeoffs with a seven channel amp. For instance, portability. According to the Outlaw website, the 770 weighs in at 90 pounds. My first guess would have been over 100, but then I’m getting older. Normally I would recommend that you have the dealer near where you buy a piece like this deliver and set it up, but since Outlaw is an Internet-only operation, you’ll get the delivery but not the setup. So, have someone on hand to help unpack and move this behemoth. A hand truck is a good idea (requirement) for negotiating stairs. It also might be a good idea to shield the ears of any young children in the room the first time you lift this thing, as certain expletives seem to naturally accompany such a maneuver.


The mass of the 770 is due to two large toroidal transformers and seven vertically oriented heat sinks (photo above). The transformers are mounted vertically at the front of the unit, and the amplifier channels are arranged neatly in rows, front to back. The top and bottom are extensively louvered to allow ample airflow. The Outlaw Audio website points out that no fans are required, but some amount of air space around the amp is necessary. The rubber feet for the 770 are the tallest I have seen for an audio component. They are not attached when you take the amp out of the box. They attach easily with the screws provided and elevate the 770 a full inch off of whatever surface you place it on. I presume that this height is to allow for airflow underneath the box. Do not defeat it by placing the amp on a carpet.


Of course, all of this attention to cooling means that the 770 will throw a bit of heat into your room. I welcomed this heat on the average cool Oregon day, but I was reluctant to fire this baby up during the brief hot spells that we get here. Once warmed up, the 770 was on the high end of what I would call warm to the touch, but I never found it to be hot.

This warming up proved to be crucial to the sound of the 770. I had to throw out review notes more than once when I realized (remembered) that after about 15 minutes of operation, the sound of the 770 completely changes. When cold, the amp sounds slightly muddied, with not as much distinction between instruments and voices as I like. Once the amp is warmed, up the sound blooms. For non-critical listening, I have my doubts that anyone would notice this. I did not make any effort to let the amp warm up first when I was just plopping down to watch a movie, and the sound was fine. Warming up was only a factor when I had my reviewer’s pen out and focused my attention.

For movies, the 770 proved to be completely involving, with voices sounding natural and distinct. Incidental sounds also were reproduced with clarity and pleasing textures that drew me in. For demanding movie music, I relied on musical numbers from "Hedwig and the Angry Inch". Let's just say I rocked out. For those other demanding movie sounds (gunfire and explosions), I use ‘The Matrix’ as my reference recording. The ‘Lobby Shooting Spree’ scene (as well as the many other shooting sprees) were reproduced with clarity and aplomb.

Overall, I was pleased with the sound, finding ample power and no particular colorations except perhaps a slight reticence in the high mids. For movies, this was hardly noticeable and perhaps welcome as a way to take the edge off some overly bright movie soundtracks. My home theater uses JMLab Cobalt 816’s for the front speakers and an 806 for the center channel. These speakers can be a little bright as well, so I enjoyed the match with the Outlaw.

Now, what to do with seven channels? It turns out that my preamp-processor will not drive a center rear without an upgrade, but I had a better idea. The Cobalts are bi-wirable/bi-ampable. To bi-wire would not require any additional amplifier channels, only additional speaker wire. Bi-wiring would only yield a modest change in most systems, I suspect. Bi-amping on the other hand utilizes two amplifiers per speaker, with one amplifier driving the woofer of the speaker, and the other driving the mid and tweeter. (The Cobalts are ‘two and half-way’ speakers, meaning that one six inch driver operates as a woofer, while an identical driver operates as a midrange. A single tweeter handles the highs.) Two sets of speaker connection posts are provided on the back. For normal operation, the connections are jumpered together. To bi-amp, the jumper is removed, and a separate amplifier is wired to each set of posts.

This not only dedicates more power to each speaker, it presents each amplifier channel with a simpler load. The complex three way crossover is replaced with the easier to drive two way. The eternal speaker conundrum is that two way speakers sound better for 90% of the musical spectrum but are missing the lowest bass frequencies. Adding the bass requires a third driver but complicates the crossover in such a way that something is lost. Potential solutions are a subwoofer, heroic, massive amplifier design or bi-amping. Bi-amping is great if you’ve got lots of amplifiers lying around. Enter the 770.

With the JMLabs bi-amped by the 770, music became completely involving. Low’s (the musicians, not the frequency range!) new album "Trust" features a typically haunting opening track recorded with loving attention. On this track the vocal part consists of one male voice and one female voice. Only in this bi-amped configuration could I hear the two voices separately. The bass guitar and drums were also more clearly separated. I was engrossed. Beck’s newest record, "‘Sea Change", is a low key affair with many sounds, electronic and otherwise in the high mid range that I was having trouble hearing before. With the bi-amp configuration, it sounded nearly as good as through headphones. I was not enjoying this record very much until I heard it this way. Switching back to movies, the presentation was more relaxed and natural. Even in the shoot-em-up scenes, each of the many sounds were distinct with no glare or edginess.

After a thorough workout in my home theater, I moved the 770 upstairs for a go in my two channel system. As heavy as the amp is, it was easier to move one heavy item upstairs than two large, heavy speakers downstairs. My music system speakers are Gold Sound 9’s, which are three-ways, utilizing 15” woofers. After the requisite warm-up period, two channels of the 770 had no trouble driving the big speakers to loud levels of enjoyable sound. I still heard the slight reticence in the upper mids. This was particularly noticeable on piano music. Still, any good recording was completely enjoyable, and I found myself listening longer than I had intended. I found that deep bass tones sounded more natural with the Outlaw than with my reference (Edge M-4). This may have been a function of slightly less control, as the Edge amps are famous for commanding bass control, but the Outlaw never sounded loose or flabby.

Problems/Complaints

In the bi-wire configuration, I heard a high pitched tone through the speakers as the amp powered off. I was able to minimize this by leaving the preamp on while the Outlaw used up its capacitive reserves after the power switch was thrown. Because of this issue, I neglected to troubleshoot the 12V trigger jack. The cable provided with the amplifier was a ‘stereo’ cable (three total conductors), while the online manual suggests that a two conductor (mono) cable is appropriate. There was also a slight 60 cycle hum when the amplifier was on but not driven. It was not audible enough to bother me. The online manual has many good suggestions for fixing hums. Only one other glitch, the speaker connectors seem to be made of thin plastic. If Outlaw needs to save money on these connectors in order to improve the quality of internal parts, then so be it. The connectors are a small issue, and I forgot about them soon after I had the amp wired up.

On The Bench (JEJ)

Single sine wave tests at 1 kHz, as well as IM tests, using 11 kHz and 12 kHz sine waves, resulted in very low distortion, as shown below. As a matter of fact, harmonics are not even visible on the graph with the 1 kHz input, and are just barely visible with the IM test.

The measured frequency response begins to roll off below 100 Hz and above 7 kHz, but is within 1 dB from 20 Hz to 70 kHz.

Conclusions

At $1,799 for 7 x 200 watts of amplification, the Outlaw 770 is clearly one of the best deals out there whether you measure by watts, channels, or pounds. Even if you are reluctant to surround yourself with more and more speakers, seven channels of amplification gives you the option should the movie world decide to go that way. Or if your speakers allow for it, bi-amping is a terrific use of the extra amps. I am so happy with bi-amping and the 770, I plan to buy the review sample. I actually wish I had even one more channel of amplification as my center channel speaker is bi-ampable as well.

Note: The power cord provided is extra heavy to accommodate the load of seven channels. The cord is not quite seven feet long, and the termination at the amplifier end is slightly larger, and with a different orientation of the blades than I have seen on other equipment. This is an electrical code requirement for 20 amp components, so you will need to install an appropriate AC wall socket if you don't already have them. Even the heavy cords seen on most audiophile amplifiers are not quite as thick as this one. The outside diameter is a full 3/8”. If you need more length, Outlaw recommends an extra large diameter extension cord. Make sure that whatever cord you use does not get warm after running the amp for a while.



- Rick Schmidt -

Related to the article above, we recommend the following:

Primer - Amplifiers

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