Reference Series Power Amplifiers
It is the holiday season and I am going to give you a present. This is the culmination of a long and winding and interesting and frustrating and expensive journey from that first audio component to hearing one that had me saying, “That’s the one!” It is the story of developing specific ideas about good sound reproduction, validating or replacing those concepts, and finding that some of these tenets no longer applied. Some of these tenets include:
Each of the above has been true at certain times in the past and with certain associated components and loudspeakers. We can generally agree that most early solid-state gear was not an advance in sound quality over the tube-based components that they attempted to replace. It was a case of “one step forward and two steps back”. We gained features and possibly reliability, but the trade-off was too great: those early transistor products often sounded like fingernails on a blackboard. Having mostly lived with tube amplifiers for about 20 years and, over the last year, performed a listening survey of some of the better solid-state amplifiers, I can state with some certainty that each technology has sonic advantages. The quest is, and has always been, to find the perfect marriage of the best sonic characteristics of the different technologies.
Tube sound is typically more dynamic – both large scale (macro) and small scale (micro). It is harmonically richer, revealing far more of the fine and delicate structure of every voice and sound, without any sense of grain or harshness. Solid-state sound is usually described as having deep and tight bass and extended high frequencies, with sound that is often marred by a somewhat flat soundstage and usually rendered painfully with grainy and harmonically thin higher frequencies. The better solid-state amplifiers have a wonderful sense of focus that renders an instrument in a very specific point in space and keeps that image intact. The better tube amplifiers have far superior harmonic development and warmth in the upper frequencies. Over the last few years, the better amplifiers of each technology have begun to sound more and more alike. My preference has been to have the much more satisfying realistic harmonic resolution of tubes and simply accept their maintenance costs and relative sonic deficiency in the bass, however small.
The list above has one tenet that I continue to hold true: high powered amplifiers are necessary to reproduce the full dynamic range of music with most speakers. This became apparent when I changed from the 100 Watt per channel Bella Extreme 100 to the 250 Watt Manley Neo-Classic 250s. Both models are monophonic tube amps. While the “Bellas” are sonically excellent, early in the audition of the Manleys it was apparent that the latter’s extra power was indeed sonically significant. Most of my listening is in the 10-30 Watt range with speakers of average efficiency. When you realize that a 10 dB peak pushes that power requirement from 30 Watts to 300 Watts, the need for lots of amplifier headroom becomes obvious. My personal “must have” list for the perfect amplifier includes deep, powerful and high resolution bass, an enormous and accurate spatial environment, richly detailed midrange, and high frequencies that are smooth and absolutely grain-free while preserving the life-like micro detail of such instruments as cymbals, flutes and piccolos, bells, and soprano voices. Add in high power, low maintenance requirements and also, in these “green” times, low heat output. This is where the Marantz MA-9S2, a 300 watt monophonic golden beauty, weighing 82 pounds with a list price of $7499.99 each, entered the listening room and life of this writer.
The review system included Manley Neo-Classic 250 and Ampzilla 2000 mono amplifiers, and Wyred4Sound ST-1000, Halcro MC20, BAT VK-250SE and VK-220, and Pass X250.5 stereo amplifiers. Sources include a SOTA Cosmos IV turntable with TriPlanar VIIu2 tonearm, Miyajima Shilabe and Air Tight PC-1 phono cartridges, Manley Steelhead phono preamplifier, the wonderful Cary 306 Professional and Marantz SA-7S1 CD/SACD players (reviews in progress), PS Audio DL III DAC with Cullen Stage 4 Mod, modified Audio Research LS22 and Sonic Frontiers Line 2SE+ preamplifiers, all providing great musical signals to Dali Euphonia RS3 stand-mounted speakers with a pair of JL Audio Fathom f112 subwoofers or my “Perfect Subs”, and the more full range Dali Mentor 5 loudspeakers from the HT system. Interconnects are Mogami and speaker cables are Audience Au24 E single wire, with Audience PowerChord E, some DIY, and Audioquest NRG-2 power cords. This system permitted operation of the amplifier in fully balanced mode from the CD player or DAC to the amplifier.
The Marantz amps have an input selector switch on the left front panel. It selects between the balanced input and your choice of two unbalanced inputs on the rear panel. I use this valuable feature almost every day. The preamplifier is plugged into the balanced connection. My McIntosh MR500 tuner has variable and fixed-level outputs. I use unbalanced cables to connect the tuner’s variable outputs to one of the unbalanced inputs on the Marantz amplifier. With a simple turn of this selector switch, I can listen to FM radio without turning on the rest of my system, prolonging the life of the tubes in the preamplifier while reducing both my electric bill and “carbon footprint”. Use a McIntosh tuner (or another brand with variable outputs) with the MA-9S2 amplifiers and you have an awesome table radio!
The front panel hosts a small push-button that turns on and off the round power meter and its soft blue backlight. The meter is calibrated in dB and a conversion chart is included in the excellent owner’s manual to convert dB to Watts. For example, -30dB on the meter equals a power output of .3 Watts (into 8 Ohms), and -10dB equals 30 Watts. If you see the meter reach 0 dB, I hope you are holding your drink tightly because the amplifier will be sending 300 Watts to your speakers. That is a lot of power! One other notable feature, found on the rear panel, is a rotary switch called “Attenuator (-dB)”. This allows you to adjust the sensitivity of the amplifier to better match the gain of your preamp or source components. The adjustments are 0 dB, -3, -6, -9, -12, or off. The off position has value if you want to change unbalanced RCA connections without turning the amplifier off. Of course, you could also select a different input with the front panel input control for the same purpose. If you use balanced cables, there is no need to turn off the XLR input as these are usually hot pluggable. Contrary to the US pro standard, pin 2 is negative or inverted, and pin 3 is positive. If this is not how your preamp is wired, simply reverse the speaker connections. No big deal. Also on the rear panel are two pairs of CE approved binding posts for bi-wiring. As you can see, there is a full set of connections and adjustments to allow this amplifier to work perfectly in a wide range of systems.
Back to the sound. I was just thinking that I should be going into the listening room and literally “get back to the sound”. However, this review is not going to get written by itself, so I will have to settle for listening to music from the adjoining room where my office is located. But that is precisely the effect the Marantz amplifiers have on me: get back to listening to music with minimal delays. There is never enough time, or enough opportunities without competing activities, to enjoy music with these amplifiers in the system. These big amps benefit from about 80 hours of break in, after which time they are clear and open sounding.
On a macro level, the virtual soundscape is huge and very well defined. The size of the recording venue is unambiguous. I get a clearer impression than with any other amplifier of the size of a recording studio and often how the individual instrument tracks were dubbed into the final mix. For orchestral or large scale acoustic recordings, a musician’s placement on the stage is always readily apparent without a solo instrument seeming to exist in a separate space. The sense of an integrated and wholly realistic performance environment is exemplary. But look right, and there is that first trombone standing out slightly from the section, or look left and clearly imagine the percussionist tapping on the triangle, about one meter outside and to the left of the left speaker. On "Deacon Blues" from Steely Dan's Aja LP (Mobile Fidelity 1-033), the saxophone in the second half of the cut pops out in the mix as a fully formed instrument with believable 3-dimensionality and solidity. These kinds of experiences occur regularly.
The bass is powerful, deep, and highly resolving, while sounding neither weak and thin nor overdone and fat or slow. Immediately after installation, there was a feeling that the bass was bettered by the Pass X250.5. Further investigation showed that the while the Pass amp’s bass was indeed just a bit louder, the quality of the MA-9S2's bass easily surpassed it with much finer resolution and inner detail. It was easier to hear individual bass strings being plucked or vibrating with the MA-9S2 amplifiers. Longer term listening revealed a finely textured bass presentation with realistic dynamic power and impact. That initial feeling was the result of a simple and temporarily uninformed comparison between two different sounding amplifiers. This is an example of the danger of making quick comparisons and then trying to draw a valid conclusion.
While the bass range fits more closely into the solid-state stereotype, the midrange and treble frequencies break previous technological barriers. It was almost impossible to hear a qualitative difference between the midrange presentation of the wonderfully involving Manley Neo-Classic 250 tube amplifiers and the Marantz MA-9S2s. All of the attributes we attribute to “tube midrange” were present. In the upper midrange and treble that sense of increased harmonic focus, which is present in the better solid-state amplifiers, became apparent without any sacrifice in the warmth, inner detail or natural, fine resolution that we regularly enjoy from vacuum tubes. The tube-like midrange continues into the upper frequencies and there is not the slightest trace of hardening or brittleness as the frequencies increase. This is such a significant departure from the stereotypical solid-state sound character that it is time to put aside this outmoded and old fashioned idea of this technology. The MA-9S2 is, without exception, the ideal blend of the best traits of solid-state and tube sound.
Solid-state amplifiers have never found a long-term home in my listening room. Depending on the particular model, they are usually dispatched after auditions lasting, and often tolerated, for mere hours or days. Reviews require a full understanding of the component’s character which often takes weeks, but the opportunity for any component to win my ears and heart is far more limited. The audition of the MA-9S2 amplifiers has continued for about 6 months with nary of thought, wish, nor desire to replace them with something else. Their performance, both overall and in each audiophile-obsessive performance category, easily meets or exceeds that of any other amplifier I have hosted in my listening room.
After a couple of hours with the power meters operating in the 30~100 Watt range, the amplifiers were mildly warm. The top cover vents were never more than just warm and certainly nowhere near the almost painful temperatures of the Pass amp. The Marantz amps are apparently not biased very far into Class A operation, but without any sonic penalty. “Class A operation is required for good sound” is another preconceived idea about solid-state amplifiers that is definitively shown to be merely an audiophile folk tale, passé and due for extinction. I hope to hear one of the lower cost amplifiers in the Marantz Reference series and see just how closely it comes to the exceptional performance of the MA-9S2.
There is only one negative I could discuss about these remarkable amplifiers. They carry a high price and there is no getting around this fact. For the price of admission, you get a beautifully crafted product with all of the features one could wish for to assure a perfect installation. Combining true tube-like magic in the midrange and treble with a rock-solid bass foundation, the Marantz amplifiers are revolutionary products. Let me state unequivocally that I love the sound of these very fine amplifiers. Their extraordinary performance and easy livability are everything I have ever wished for in a power amplifier. The Marantz MA-9S2 Reference Series power amplifiers have taken up permanent residence as my references. Check them out. Happy listening!
Overall Rating: 10 LPs
Manufacturer's Web site: Marantz America