Jeff Rowland Design Group Model 302 Stereo Amplifier

Jeff Rowland Design Group Model 302 Stereo Amplifier

More than Meets the Eye

Greg Petan

26 July 2003


Output power: Continuous RMS watts both channels driven
300 Watts, @ 8 ohms
500 Watts, @ 4 ohms
Power Bandwidth: 5 Hz – 60kHz, 3dB
Peak Output Current: >45 Amps
Dynamic Range: 117 dBA
THD + Noise, 0.1W-500W/4 ohm <.05%, typically .006 @ 1kHz
CCIF Intermodulation Distortion, 19/20kHz <.002%
Damping Factor @ 1 kHz 275.
Overall Gain:
(Balanced or Unbalanced) Selectable Internal Jumper,
26 or 32 dB
Input Impedance: 40k ohms
Common Mode Rejection Ratio: >90dB, 20 Hz 20 kHz
Absolute Phase: Non-inverting, Pin 3 Positive
Inputs: User-selectable
2 × Balanced XLR
2 × Unbalanced RCA
Outputs: 2 Pairs Parallel Binding Posts per Channel
Standby Switch OFF: 85 Watts
Standby Switch ON (idle): 100 Watts
Maximum: 1200 Watts
Weight: 95 lbs
Dimensions: 15.5″ (w) × 10.6″ (h) × 18.3″ (d)

Jeff Rowland Design Group
2911 N. Prospect
Colorado Springs, CO 80907
P.O. Box 7231
Telephone: (719) 473-1181

The new Jeff Rowland Design Group Model 302 stereo amplifier (there is a mono, three, and four channel version available as well) settled into my system with some distinct advantages. First, I generally favor solid-state amps over tube amplifiers, as I need a lot of power for my speakers and my cavernous listening space. Second, the 302 could only be sexier if you put a bikini on it and slapped it on the cover of the Sports Illustrated swimsuit issue. And finally, I have known Jeff Rowland, the man, for several years and I have to admit there are few people in or out of the industry that I admire and respect as much as the big guy from Boulder, Colorado (At 6’8″ the phrase “big guy” is fitting!). While these traits ensure getting off the line quickly, the competition in the solid-state amplifier sweepstakes is fierce around here these days and the Model 302 would need more than just a pretty face to win this audiophile’s heart. 

Jeff Rowland Design Group was born directly out of the need for power. In the early eighties, the ubiquitous Apogee Scintilla full range ribbon speakers and their insatiable need for power were snuffing out the lower powered amps of the day like dropping matches into a toilet. The only amplifiers that could drive those beasts were some of the pro-audio stalwarts that were big on drive but sadly lacking in finesse. At the urging of the audiophile community, Jeff designed the Model 7. Word quickly spread of the wonder-amp that tamed the Scintilla. Soon thereafter, Jeff sold off his stake in Avalon Acoustics and before long, Jeff was full-timing it as an amplifier manufacturer. (Dan and Rhondi D’agastino Of Krell came into being at the same time and for the same reason, thank you Apogee!).

I have owned and reviewed the original Model 8 and Model 8TiHC stereo amplifiers, as well as the Coherence II battery powered preamp giving me a bit of context with which to judge Jeff’s latest offering. In order to make room for the new Model 302, I let go of my 8TiHC. This was not an easy move for me. I found the 8TiHC such a wonderful piece of gear and at the time of this writing, I still miss it. Warm and powerful, satisfyingly transparent and delicate, that amplifier never failed to engage me musically. 

The Model 302 takes Jeff’s vision into the future with the implementation of Jeff’s proprietary digital switching power circuitry. Dubbed MECC (Multivariable Enhanced Cascade Control), this circuit is neither class D nor any other existing classification, simply the fruits of Jeff’s meditations on circuit design and an expanding inventory of innovative digital hardware. Thanks to the MECC circuit, the Model 302 is far more electrically efficient than its predecessors-not an insignificant concern to the admittedly “green” leaning Jeff Rowland (due to this efficiency, the Model 302 never got more than slightly warm). While Jeff has moved back to the Model 8 chassis design for the Model 302, the overall dimensions have been reduced, as has the weight. The weight savings are made possible by the reduction of the large capacitors featured in Jeff’s past designs. The chassis has also undergone extensive structural redesign, yielding the most rigid resonant-free structure Jeff has ever designed. And that face plate! If I were an NBA star, I would forego the obligatory three-carat diamond stud earring and clamp a Model 302 to my earlobe. With the Model 302 weighing 90lbs., I would have to be 16ft tall and a rather Shaq-like 750lbs to pull this off! 

For most manufacturers, “next generation” products tend to maintain the essence of it’s sonic lineage. In the best-case scenarios, incremental improvements become consolidated as strength builds upon strength, while weaknesses are marginalized or eradicated. Despite many manufacturers’ claims that the new model “blows away the old”, I rarely find that to be true.

Having owned the original Model 8, the Model 8TiHC, and having auditioned the Model 12, I thought I had a pretty good Idea of what to expect from the Model 302. As many have observed, Jeff’s amplifiers tend to have an inviting warmth from the low bass through the midrange, and a sound that possesses body and color, while perhaps lacking the last measure of high frequency extension and transparency. Even the 8TiHC, having opened the high frequencies considerably from its predecessor, maintained a pretty strong family resemblance to the original Model 8.

Having grown so familiar with Jeff’s amplifiers, it is to my great surprise that the Model 302 has evolved into a different animal from its ancestors. Gone are the slight, yet un-mistakable, sonic embellishments of Jeff’s past designs. Gone is the high-frequency roll-off. Gone is the rolling bass and mid-bass. The only thing that really resembles the Model 302’s lineage is the faceplate and a healthy dose of sonic magic the Jeff brings to everything he designs. This quantum change caught me off guard and forced me to carefully listen to what Jeff was onto sonically with the Model 302.

After a very real three hundred hours of burn in, I began to put my ears to the Model 302. For some reason, this amp needs a bit more time to flesh out than other amplifiers I have reviewed. The first thing that struck me was how open and transparent the sound was. Sounds are more discreet, layered and delineated than in the past Rowland designs. There is a sense of unlimited resolution and focus available to any bit of action within the soundstage. The cumulative effect is a feeling of effortlessness, openness and speed. Transient response is much quicker than I have experienced from Jeff’s amps in the past. The sense of depth into the far reaches of the soundstage is quite remarkable. Thanks to an incredibly low noise-floor, there is little if any obfuscation anywhere on the stage. Like the Pass X600s, the Model 302 is as clear as a Canadian vista. Yet, the Rowland didn’t flatten the sound stage as the Pass X600 slightly tends to. Compared to the Pass X600, the model 302 expands the dynamic scale as well, sounding a bit livelier in the mid-range and into the treble. To the X600s credit, the Model 302 could not quite keep up with the 600 watt mono’s over-all dynamic slam, though it was a whole lot closer than I thought it would be given the disparity in the power rating.

For most components that embody the traits mentioned so far, there usually comes the less than desirable bi-product of a lean tonal balance. Here is what I have had the most trouble in identifying or quantifying in the Model 302. Compared to the Krell FPB 700cx, the Model 302 is decidedly sunnier and airier, with a sparkling treble full of detail. While the Krell doesn’t suffer for upper-octave resolution, there is a greater emphasis on this area with the 302. Through the mid-band, this open sunlit quality remains, exposing any and all detail and textural shading. Where the Model 8TiHC may have “summed-up” some mid-range detail, the Model 302 extracts detail and leaves little mystery. For those of you who may have stayed away from Rowland amplifiers in the past because of a lack of resolution and high frequency extension, the model 302 may be the amp for you. 

As for the issue of leanness, I exhausted the contents of forty to fifty recordings to nail down an affirmative conclusion to this issue. As usual with a high quality high-end audio product, great recordings sounded splendid and poor recordings sounded appropriately detached from reality. The fact that great recordings sounded their best was not so much a surprise. What was a shock was that poor recordings through the Model 302 revealed previously undiscovered nuggets of sonic gold. For instance, Pete Townsend’s musical masterpiece and sonic hack job Empty Glass (Atlantic 82811-2) proved to have greater harmonic integrity, dynamic nuance and detail than I had thought. Yes, the over-all quality was still quite low but the improvement wrought by the Model 302 made the recording more interesting and involving. On the opposite end of the production scale, Duke Ellington’s Ellington Indigo (CK44444) featuring a stunning rendition of “Autumn Leaves”-which couldn’t sound bad if played back on a clock radio-sounded spectacular. The timbre of the voice was just stunning. With the Model 302, there is an intimacy with the performance and a truth revealed that makes this performance feel as though it’s happening for the first time, just for me, every time. Disc after disc, this dynamic played itself out, if to varying degrees. It all depended on the source material. Yes, the Model 302 is essentially neutral. In the end, I still can’t get over the feeling there may be just a touch of harmonic subtraction in the upper-midrange that contributes to the sensation of airiness and a lighter overall tonal shading than that of dead center neutrality.

Once I came to peace with that issue, I was able to completely sink into the Model 302. This is a piece of gear that just begs to be used and abused. Go ahead and push it to the brink of its rated 300 watts into 8 ohms. The Model 302 just unleashes dynamics, driving the bass with iron-fisted precision and great timbral accuracy, while never adding any edge whatsoever. Compared to the 8TiHC, the low frequencies are tighter, more defined, and possess greater reach. Confronted by the torture test that is Joe Satriani’s Engines of Creation (EK67860), the title track “Engines of Creation” filled the room with pools of chest thumping bass. Friends who know my system really well were stunned with the low frequency control of the Talon’s woofers provided by the Model 302. If you like electric guitar music, this recording is a must. Surprisingly, the Model 302 gave the big Krell a run for its money in the low frequencies. And where the 8TiHC may have of rolled over, showed it’s under belly, and lost its grip on bass, the 302 pinned its ears back and snarled. While the Krell presented bigger bass through the mid-bass, the Model 302 sounded a bit tighter, quicker, and more focused in this region without suffering much for impact. 

In a fevered state and just because I could, I lashed the Model 302 up to my Avalon Radians, tri-wiring them with three different, very high-end wires from three different companies. This was one of those classic mad audiophile experiments that in all probability would end in some form of sonic disaster or massive mechanical failure. With the MIT Oracle V2 on the bass, the Silversmith’s on the mids and the Shunyata Phoenix on the treble, the sound was a surprising success-and nothing blew up! The bass, in particular, showed that the Model 302 is capable of even greater reach than I had previously thought. On Stanley Clark’s Live at the Greek, (EK57506) the opening track, “Minute by Minute”, opens with over-lapping bass and keyboard riffs that build into the melody. The power and texture of the bass was jaw dropping. I thought I had heard all the Radians have to offer in this region, but clearly there were a few tricks left up their woofers. This little exercise showed the Model 302 to be one stable and compliant amplifier that should last for the long haul.

Conclusion-Part one

The high-end is clearly in the process of revolution by way of evolution. With the advances being made in digital technology, and from what I have heard from our editor Clement Perry’s rig (which features the TacT digital room correction preamp/processor and amplifiers), there is little doubt about which way the winds of change are blowing. And when someone like Jeff Rowland-a designer who never does anything gratuitously-embraces change, there can be little ambiguity: digital circuitry is the future.

I can hear the collective gasp of indignation rise among the masses of analog devotes the world over. Before you lock your sights on me, let me make a few things clear. First off, I could care less if it is digital, analog, solar, diesel, hydro or a hamster running on his spinning wheel; whatever gets the job done is fine with me. I have nothing personally invested either way. Whatever the means, the fact is that there are things that can be done efficiently in the digital domain that cannot be realistically achieved in the analog realm. Secondly, while there is room for incremental improvement in the analog domain, the ability to infinitely manipulate a digital signal as shown by products like the TacT, digital circuitry will yield the greatest gains in sound reproduction going forward.

Conclusion-Part two

As I step off my digital soapbox, I realize that this is an expansive hobby populated by all types of tastes and needs. Heck, I still want to add a great tube amp and turntable to my system one day. If we can agree that seeing the future in no way negates the past, then we can probably agree that the Jeff Rowland Model 302 amplifier represents an artistic achievement, as well as a technical flier into the future for Jeff Rowland. Through the deft touch of a master’s hand, the Model 302 re-defined for me, what to expect from an amplifier. Delicate and textured, enormously powerful and fast, the Model 302 leaves no sonic stone unturned. This is an amplifier that, once warmed up, will have the listener totally un-concerned with the technology, and totally immersed in the music.

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