- The HCE Video Series
What is an amplifier really? For many, both audiophiles and home theater enthusiasts alike, an amplifier is the heart, and in some instances, the soul of any system. The human heart is a good metaphor for the modern power amplifier, for like the heart, an amp “pumps” your system’s lifeblood to your loudspeakers. Without an amplifier there would be no sound. But does this make all amplifiers the same? No, not by a long shot. Amplifiers come in a variety of shapes, sizes, channel configurations and power outputs. Within each of those categories there seem to rest a dozen more sub categories and so it goes. When it comes to home theater, the most commonly seen amplifiers are ones often referred to as multi-channel, or amplifiers that are capable of driving multiple loudspeakers at once -typically 5 or 7. The Sherbourn PA 7-350 (7-350 ) reviewed here is of the seven channel variety meaning it can power up to 7 loudspeakers at once in a surround sound environment or setup.
It’s not that the 7-350 is the only 7-channel amplifier in existence -it isn’t -but among its peers it’s two things; first the 7-350 is one of the more powerful 7-channel amplifiers you’ll find and two, it’s relatively affordable given said power. But I’m getting a bit ahead of myself. For starters, the 7-350 is Sherbourn’s current flagship, multi-channel amplifier. Sherbourn, for those of you who may be unaware, is the custom install friendly lineup of products produced by Jade Design -the parent company of Emotiva. Sherbourn started off in life as its own brand before being purchased by Jade Design a few years ago. Under Jade Design, Sherbourn has remained a CI staple, though its sales methodology has shifted away from traditional brick and mortar to Internet direct sales -a la Emotiva. It’s not that Sherbourn isn’t still available to installers and dealers the world over -it is -it’s just also available to consumers too, albeit direct. Because Sherbourn’s products are sold direct via the Internet their prices are a bit more advantageous than some of its direct competition. With regards to the 7-350, it retails for $2,519, which includes shipping as well as a full, 10-year factory warranty (5-year transferable) . The 7-350 also comes with a 30-day, in-home trial period at the end of which, if you’re not completely satisfied, you can return the amp to Sherbourn for a full refund.
What you get in the 7-350 for a hair over $2,500 is rather impressive. From the outside, the amplifier itself is rather imposing, measuring 17 inches wide by nearly 10 inches tall and 19 inches deep. It also weighs a “metric ton” at 99 pounds out of the box. Like all Sherbourn products, the 7-350 comes with the requisite rack mounting hardware as standard, which is good for most AV rack shelves are not rated to support such weight. From the outside the 7-350 is basic but still beautiful. Its smooth black finish is accented by subtly sculpted lines that run horizontally along the bottom edge of the amp’s facade. Within this horizontal band and positioned off to the left (when looking at the amp itself) you’ll see the amp’s polished silver standby button flanked by seven small LED lights. The LED lights are the amp’s indicator lights that glow amber when in standby and blue when in use. The top of the 7-350 is dominated by vents that help keep the amplifier’s internals cool and should be left clear of any obstructions, this includes other equipment, when the 7-350 is in use. Around back you’ll find the amp’s input and output options, all of which are thoughtfully laid out with tons of space between each in order to facilitate proper cable management.
Looking at the back of the 7-350 and moving from left to right, top to bottom, the first thing you’ll come across is the amp’s seven unbalanced inputs. Below each unbalanced input rests a small toggle switch that allows you to select between the 7-350′s RCA style inputs (unbalanced) and its balanced or XLR-style inputs. Again, all seven channels are clearly labeled and spaced out appropriately to accommodate all types of cable be it balanced or unbalanced. Across the bottom, each amplifier channel possesses two sets of five-way binding posts. Why two sets (four) and not a single pair? The 7-350 has two sets of binding posts per channel to better facilitate bi-wiring. If your speakers don’t have two sets of binding posts or you simply don’t care about bi-wiring, don’t stress, for both sets of binding posts run in parallel meaning you can easily just use one and not the other and be just fine. Along the far right side of the 7-350′s back panel there are two trigger input/outputs, a switch to defeat the front mounted LED indicator lights , a master on/off switch and the amplifier’s 20-Amp power cord receptacle. That is right, the 7-350 requires a 20-Amp power cord, which also means it must be plugged into a 20-Amp outlet -more on that later.
The 7-350 is a fully discrete, dual differential, high current Class A/B amplifier that utilizes a SoftSwitch Optimized, Class-H power supply inside. Now, there is much to do over an amplifier’s Class among enthusiasts. Audiophiles tend to like Class A designs, whereas most home theater amplifiers utilize a Class A/B methodology. In recent years Class D has come into vogue. Class H isn’t “new” though admittedly it’s not as prevalent as the before mentioned options. While Class H is different, it’s not wholly unlike A/B -it’s just a little more efficient. At the end of the day, a properly implemented A/B and H design shouldn’t sound too different from one another, so don’t get hung up on the 7-350 or any amplifier’s Class designation. That being said, the 7-350 possesses a 3.3kVA toroidal power transformer inside with 180,000 uF storage capacitance. What is more important is the 7-350′s stated power output, which in this case is a healthy 350 Watts per channel into 8 Ohms and 550 Watts per channel into 4 Ohms. That’s a lot of horsepower, and for some it might seem like too much.
There is a misconception that if a speaker’s maximum power handling rating is said to be say 100 Watts, then your amplifier should not exceed that rating. This is a myth. That figure of say 100 Watts means that for sustained periods that is all the power the speaker can handle. The truth is, music and/or movies, are not constants, meaning they don’t play one note at one volume for an indefinite period of time -unless of course your name is Kenny G. Because the music and/or soundtrack changes so does its need for power. At any given point your amp, in this instance the 7-350, could be churning out 10 to 30 Watts -a far cry from your speaker’s 100 Watt max. If most of the time the amp is only producing 10-30 Watts (just an example) why then do you need 350 Watts? It’s called headroom. Like a super charger to a car engine, the copious amount of power on tap is there to safely drive your speakers to their limit and thus recreate the full scale of the music or cinema event without distortion or damage being done to you speakers or your ears. You see power doesn’t “cook” speakers, distortion or “bad power” does.
With regards to the 7-350′s distortion, it is incredibly low -less than .02 percent. Signal to noise is reported to be 76dB at 1 Watt (A-weighted) and 100dB at rated power (again A-weighted). The 7-350′s reported frequency response is 20Hz to 80kHz (+/- 2dB). Input sensitivity is rated at 1.7 Volts and gain at 32dB.
The 7-350 arrived hot on the heels of my review of Parasound’s Halo A 21 amplifier. I had been running two Parasound Halo amplifiers, the two channel A 21 and three channel A 31, prior to the 7-350′s arrival. Obviously, the 7-350 allowed me to employ a single amp rather than result to using two, though using two amplifiers or sometimes more isn’t uncommon in multi-channel or home theater setups. Does employing a single, 7-channel amp simplify things? Yes, but do you need to rely on an all-in-one solution? No. The 7-350 comes with the requisite hardware to facilitate rack mounting out of the box, which is a good thing. I un-installed my two Parasound Halo amplifiers and inserted the 7-350, with its included rack ears attached, into my Sanus equipment rack. I suggest having a friend or two help you with this as the 7-350 is quite heavy and can be very unruly should you try and mount it yourself.
Once mounted inside my rack using the bottom four spaces I made sure to allow for plenty of ventilation by keeping the next five or so rack spaces above the 7-350 free of any and all equipment and/or obstructions. This meant using a couple of rack blanks to keep things looking neat and tidy. Once installed I connected the 7-350 to a variety of AV preamps beginning with my Integra DHC 80.2, Sherbourn’s PA-7030 ($1,619) and Emotiva’s UMC-200 ($599). Each preamp worked nicely with the 7-350, though for the bulk of this review I opted for the Sherbourn PA-7030 and then later the UMC-200.
I connected the 7-350 to the PA-7030 via balanced interconnects from Monoprice. I only have a 5.1 channel setup so two of the 7-350′s channels sat unused for the bulk of my review period, though at one point I did bi-amp my front left and right mains to positive results. Speaking of my speakers, I utilized my reference Bowers & Wilkins CT 8.2 LCR speakers, that I connected to the 7-350 via custom lengths of 12-gauge speaker cable from Binary, a SnapAV company. For source components I used my trusty Dune-HD Max media player, Pioneer Elite’s BDP-62FD universal disc player and a Roku 2 XS media streamer. The whole setup was controlled via a custom remote programmed in iRule. For video I relied on my reference LED based front projector, SIM2′s M.150. It should be noted that my front three speakers sit behind a 120-inch, acoustically transparent screen from Elite Screens’ EPV line of Lunette screens.
Before I go any further I should also note that because the 7-350 requires a dedicated 20-Amp circuit complete with a 20-Amp outlet I had to call an electrician to have one installed in my home. I actually had two installed as more and more high-powered amplifiers are starting to require such connection options. Needless to say, the cost of adding a true 20-Amp circuit to one’s home should be factored into the 7-350′s true cost of ownership, though the cost of having a 20-Amp circuit installed needn’t be too expensive. My two 20-Amp circuits cost me under $200 total and were able to be installed in less than 2 hours.
Starting with simple two channel music, I cued up Counting Crows’ album, Films About Ghosts (Geffen Records), and the track “Anna Begins.” The first, most noticeable trait of the 7-350 was its rock-solid imaging from the center outward. Every performer was grounded, and occupied their own distinct space, side-to-side and front-to-back. The delineation between each performer, their respective instrument and physical space within the performance space bordered on laser etched, but not in bad or artificial sense. As a direct result the soundstage itself was more an organic “orb” of sound rather than a “T,” whereby the vocalist and guitars rested on a lateral plane with the drums and perhaps other percussion accompaniment falling back of center. Speaking of accompaniments, the track’s piano was more resolved and nuanced via the 7-350 than with prior amplifiers. The piano’s presence improved as did its inner detail, as key strikes and the following reverberation within the body of the piano itself were all the more audible and three-dimensional. The piano, like the rest of the instruments present during the track, was natural in not only its tone, but thanks to the 7-350′s power, it was also true to life in its scale. The same was true of lead singer, Adam Duritz’s vocals. I wrote in my journal that, “the 7-350 unravels and reveals music like peeling back the layers of an onion.” It’s not as if prior amplifiers gloss over or outright “miss” aspects of the incoming musical signal -they don’t -it’s just that the 7-350 seems to have an easier go of things. The resulting sound is one of effortless control and composure that is a touch laid back but not vague. This slight “mellowness” does cost the 7-350 some (emphasis on some) dynamic lag, but nothing that is too distracting or even unpleasant. Explosive? Maybe not dynamite explosive, but still always appropriate, especially with the finer details. The high frequencies are too a bit laid back, but not recessed or rolled off; no they extend fully and with terrific air and decay. The 7-350′s treble performance, even at volume, is the very definition of composure and try as I might, even with Duritz’s sometimes “squeaky” vocals, I couldn’t get it to act up nor become fatiguing.
Moving on I cued up Hans Zimmer’s “Seville” off the Mission Impossible: II Soundtrack (Hollywood Records). The opening flamenco inspired guitars sounded, well, like real flamenco guitars. Again, the inner detail and nuance such as the resonance of the guitars themselves, was rendered faithfully and fully. There was palpable body throughout the mid and lower midrange that carried on through to the bass, and to the heavy taps and occasional stomps of the flamenco dancers throughout. Admittedly, and this may be the fault of my AV preamp, I’ve heard slightly greater control in the lowest reaches of my Bowers & Wilkins CT 8.2 LCRs, but not by much. Like with the 7-350′s slightly “relaxed” dynamics, the 7-350′s bass control is just an ounce shy of being the best I’ve ever heard. That being said, the low frequency performance of the 7-350 is incredibly resolute, textural and nuanced throughout. I’ll take all three of those traits in lieu of an ironfisted grip any day -but that’s just me. Again, the soundstage was incredibly three dimensional side-to-side and front-to-back, showing little concern for my room’s physical boundaries -though admittedly this is as much a loudspeaker trait as it is the 7-350′s. The whole presentation was jovial and dramatic and rendered brilliantly via the 7-350.
Taking things a step further, I cued up Disney’s Tarzan on DVD (Disney) and selected its Dolby Digital soundtrack stem. The opening 5 minutes or so of the film is rife with everything from low, plodding bass to explosive high frequency information -all of which, via the 7-350 was brought to life with vigor. The opening drums that reveal the film’s title were explosive, so much so I literally snapped back in my seat. But rather than just mow me down with raw, unbridled power, there was an incredible level of detail and resolution throughout the brief, but vigorous drum sequence. Also, the spaciousness to the above referenced sequence was jaw dropping. I have nearly 4 feet worth of real estate behind by screen and rarely do I feel as if all of it is “filled” with music -no so with the 7-350 as it occupied all the space behind my screen and then some with Tarzan´s Dolby Digital mix. More importantly, even at reference volumes (100+dB), the 7-350 was the very definition of control. Remarkable.
Next, I cued up Outbreak on Blu-ray disc (Warner Bros.). I chaptered ahead to the vocal showdown between Dustin Hoffman’s character and Morgan Freeman’s inside Freeman’s Army trailer. Via the 7-350, the resulting sound was one of natural timbre, inflection and scale. Dialog sounded natural -well, recorded natural -with organic weight and definition throughout the midrange. What I wasn’t expecting was how resolved and focused the 7-350′s high frequency performance was with this particular track and/or mix (DTS-HD), because the scene’s “room tone” was far more dimensional and otherwise present than in prior demos of this same scene. The audible “air” present in the mix further helped to define the scene’s or should I say location’s cramped physical space -a space I was transported to via the 7-350. Other amps that I’ve demoed, regardless of price, have put this scene’s room tone so far in the back as to relegate it to simple “noise” whereas the 7-350 brought back its true dimension, which was very, very cool.
I ended my critical, but still subjective, evaluation of the 7-350 with another Blu-ray favorite, Moulin Rouge! (20th Century Fox). I skipped ahead to the Roxanne Tango sequence and set the volume to near reference and was simply blown away! Like with the room tone test in my Outbreak example above, the 7-350 seemed to reveal more layers to the mix that went previously unnoticed, or were somewhat “glossed over” by other amplifiers, especially in the all too critical midrange. The harmonies, self or third party, to the chorus of the “Roxanne Tango” were in full effect and were not only more audible, but so resolute as to make me wonder why other amps don’t “latch” on to such info as well. It’s not as if I hadn’t enjoyed the scene or film prior – I did -but suddenly I felt as if I was hearing aspects of the mix anew. There was just that much more information being not only communicated to me, but presented in such a way that it helped to further “flesh out” aspects that hadn’t gone unnoticed prior. The movements of the dancers themselves were so much more fluid and rhythmic in their mix and at times aurally violent, which was appropriate given the song. The depth to the sound, both physically and figuratively matched the visuals on screen to a T and helped to draw me into the performance in ways I haven’t experienced in some time. Moreover, there was seemingly no end to the 7-350′s power and control, and yet I was never made aware of its presence. Sound just happened. Loud or soft, foreground or back, the 7-350 just presented it the way I believe it was intended. It was breathtaking. It was brilliant.
Things to Consider
The 7-350 is among the larger amplifiers that I believe I’ve ever encountered save maybe my time spent with Mark Levinson’s No 53 monaural amplifiers. Because of its sheer girth, you must pay special attention to your equipment rack’s load specifications to ensure the 7-350 and the rest of your equipment’s safety. Failure to do so may result in broken shelves or worse, a broken 7-350 and/or associated equipment. Also, though the 7-350 never got too hot to touch, or even really hot, proper space above, below and to the sides of the 7-350 itself for ventilation is a must to ensure optimal performance over the life of the amplifier itself.
The 7-350 comes standard with a 20-Amp power cord and therefore must be plugged into a 20-amp outlet, preferably on its own dedicated circuit. Since most homes do not come standard with such amenities, one (or two) 20-Amp services may have to be installed by a 3rd party -i.e. professional electrician. This does add a bit to the 7-350′s overall cost of ownership, though it needn’t break the bank. In the area surrounding where I live (Southern California) I was quoted between $150 and $350 by electricians readily found via the online service Yelp.
Outside of those two caveats, I didn’t find much fault with the 7-350 in its day-to-day operation, performance and livability once installed.
Like I said earlier, the 7-350 isn’t the only 7-channel amp in existence. Right off the bat the most comparable 7-channel amp has to be Outlaw’s Model 7900. The 7900 retails direct for $3,499 and churns out a healthy 300 Watts per channel. The 7900 utilizes a slightly different topology compared to the 7-350, which is why it not only requires 2, 15-Amp circuits but also has a slightly different power rating and physical weight. Obviously, like the 7-350, the Model 7900 is a beast and then some and is the most comparable 7- channel amp on the market that I can think of. Whether or not the Model 7900 is better or worse is up to the end user.
Other notable 7-channel amplifiers include Lexicon’s ZX-7 ($7.999) and RX-7 ($5,999). ATI’s AT3000 Series amplifier ($3,995) and McIntosh’s MC207 ($6,000) amplifier. All of the before mentioned options are fine choices if you’re in the market for a high-powered, 7-channel amplifier for home theater use. There is no “right” or “wrong” amplifier, however, if your budget is tight, the Sherbourn PA 7-350, Outlaw Model 7900 and ATI AT3000 Series are the better value in my humble opinion.
At a hair over $2,500 direct what Sherbourn has done and is offering direct to its customers via its own website is nothing short of astonishing. I’m not aware of any other amplifier that possesses this much raw power at its price than the Sherbourn PA 7-350. It’s not perfect, no amplifier or audio video product is, but for what it is, it’s truly something special. While some consumers, present company included, may not need or even use all 7 of the 7-350′s channels; I still argue it’s a good value for the added power output over Sherbourn’s most comparable 5-channel amp, the PA 5-200, is definitely worth it. If you have speakers that have the ability to be bi-wired/bi-amped than you can put the 7-350′s extra channels to good use by doubling up the power to your stereo mains.
Regardless, the 7-350 is an amp that can most assuredly “hang” with the big boys in the high-end space without you having to reach too far into your wallet in order to do so. While my recommendation for the Sherbourn PA 7-350 may seem like a foregone conclusion, I ask that you please check your cynicism at the door for the 7-350 is really that good.
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