Music Reference RM-200 Mk.II power amplifier Page 2
JA's measurements of the various taps' total harmonic distortion plus noise vs frequency indicated that "When its output transformer is matched to or less than the load, the RM-200 offers superbly low distortion from the upper bass through the midrange to the mid-treble. With lower-impedance loads, the distortion rises significantly with the degree of mismatch between the output tap and the load."
So choosing the optimal tap should take into account your speakers' nominal impedance as well as the lowest impedance they dip to. My Wilson Audio MAXX 3s dip down to 3.4 ohms at around 20Hz, so I began my listening with the RM-200 Mk.II's 4 ohm tap. I felt the speaker's impedance low point wasn't much below the tap's impedance. For whatever reasons, and whether or not it shows up in the measurements, switching to the 2 ohm tap closed in the top end and dulled the Wilsons' sound. My advice: Try the various taps to find which sounds best, taking into account your speakers' impedance curve.
Otherwise, setting up and using the RM-200 Mk.II was simple, as was using a good digital voltmeter to occasionally monitor the bias readings. (Modjeski prints the bias information right on the amp behind the output terminals.) These proved stable from the time I bought the review sample until the time of writing, many months later.
Modjeski no longer supplies an AC cord with the RM-200. He figures that, at this point, "everyone has a drawer full of computer cords or better." Just for the hell of it, I tried a computer cord. Stan Getz sounded like Bill Gates, so I tried some better ones. Shunyata Research's King Cobra CX ($3500) produced the smoothest, most open, transparent, and "direct" sound, but Shunyata's Anaconda CX ($2000) sounded almost indistinguishable in this application.
The RM-200 Mk.II's basic price is $4200; even the Anaconda CX probably costs more than the power cords most buyers of a Music Reference will start with. I suggest Tel-Wire's 5' cord ($800, www.telwire.net), which has an Oyaide plug and an IEC connector, and conductors of continuous-cast Ohno copper. The Tel-Wire didn't sound quite as open and detailed as the Anaconda CX, but its somewhat sweeter, more laid-back character might better suit some systems, and its price is more in line with the cost of this amp.
I drove the original RM-200 single-ended, using RCA-to-XLR adapters. This time I used a pair of Ypsilon BC-1 transformers to convert to balanced the single-ended output of my Ypsilon PST-100 Mk.II preamplifier, and ran XLR cables to the Music Reference.
The capacitor-forming mode meant that, within a minute or so of my hitting the Play switch on the top panel, the RM-200 Mk.II delivered close to its full sonic performance.
Better than the Original?
The RM-200 Mk.II sat in my listening room between a pair of nearly coffin-sized MBL 9011 monoblocks, also in for review. With the lights on, you could barely see the tubes glowingyou'd be surprised how many visitors thought they were listening to the big amps.
Fed by the Ypsilon PST-100 Mk.II preamp in passive mode, the 100Wpc Music Reference effortlessly drove my Wilson MAXX 3s"effortlessly" in the sense that, unless I reconnected the big MBLs or the Musical Fidelity Titan, I hardly missed the lessening of dynamic slam with some recordings. In some ways, in fact, I missed more when the RM-200 was out of circuit, so balanced and appealing was its overall sound.
A direct comparison of the original and Mk.II versions of the RM-200 wasn't possible, unfortunately. But while much in my system has changed since the last time I heard the RM-200, Wilson Audio's MAXX 2s had already been replaced by the easier-to-drive MAXX 3s before the Mk.II arrived, so I did have a chance to hear the original amp with the newer speakers.
I'm fairly certain, therefore, that the Mk.II's performance at the frequency extremes was better than the original's, which itself was very good. The low bass was more robust, better damped, and texturally more refined, with a faster, more cleanly defined attack. No matter the musical genre, electric or stand-up bass, the foundation felt complete. That wasn't the case with the original amp, through which electric bass guitar just seemed too soft.
The original RM-200's top end was very airy, extended, and open, but, if anything, a bit too crisp, and not as refined as I've heard elsewhere. The Mk.II's top-end performance combined extension with a refinement of the leading edges of transients. With its bottom-to-top consistency of attack, the amplifier produced a sound that was never "tubey" in the negative sense, nor did it sound too sharp or "crisp," a descriptor best reserved for potato chips or white wine.
Larry Young's Unity (LP, Blue Note 4221) features Joe Henderson on tenor sax, Woody Shaw on trumpet, Elvin Jones on drums, and, of course, Young on organ. To my ears, it's one of engineer Rudy Van Gelder's best recordings from the 1960s, particularly as he didn't have to contend with a pianoan instrument that often sounds boxy in his recordings. He gets sensationally visceral cymbal sound from Jones's kit, which sounds to be miked more closely and mixed with less reverb than were usual for Van Gelder.
Only after writing an enthusiastic review about this album's music and sound for my website, and remarking on the superb cymbal sound and how three-dimensional and stage-forward Young's organ is, did I remember that I'd been listening to it through the Music Reference RM-200 Mk.II driving the MAXX 3s. That's significant; it demonstrated the amp's ability to get out of the way and just let the music through without announcing any sonic shortcomings.
The recent two-LP reissue of Eric Clapton's classic Unplugged (Reprise 468412-1) sounds far better than the original mid-1990s single-LP edition. Through the RM-200 Mk.II, the attacks of the steel strings couldn't be faulted, and the resonant wooden guitar bodies generated a controlled warmth that was fully conveyed by the Music Reference.
The biggest difference I noted when switching to the solid-state Musical Fidelity was a bit less warmth in the lower midbass and somewhat less generous sustain. Tube-amp magic is in the sustain, which contributes to the overall feel of generous musical flow. Soft attacks, particularly in the bass, plus excessive sustain or too much warmth in the lower mids and upper bass, produce excess softness, lackluster rhythm'n'pacing, and a generally muddy foundation.
The RM-200 Mk.II delivered Clapton's "Tears in Heaven" fully realized, with convincing acoustic guitars, a nicely rendered triangle, clean percussion, precisely placed and easily delineated background singers, and a very strong bass line that was deep, well defined, and never merged with the warmth of the acoustic guitar's wooden body. In fact, I don't see how you could fault the RM-200's rendering of this trackunless you play the headache-inducing original CD version, which proves correct everything negative anyone ever said about the CDs of that era. Not even a supposedly "euphonic-sounding" tube amp can help that bright, edgy, flat, strings-without-body mess.
The Modern Jazz Quartet's recently issued The Complete Atlantic Studio Recordings 195664 (Mosaic MD7-249) is a seven-CD set containing 14 studio albums, copies of most of which have been on my shelves since 1964. The sound quality varies. Recording the vibraphone is difficult enough; add piano, bass, and drums and you have a potential sonic nightmare, especially back then.
Despite the MJQ's academic gestalt, their instruments produced sudden, sometimes volcanic dynamic swings. One of my favorites of their albums is 1964's Collaboration (LP, Atlantic SD-1429), which adds Laurindo Almeida on guitaranother instrument that's potentially difficult to record, especially in the context of piano and vibes, which occupy similar slices of the audioband. The music, which has a Spanish flavor, includes some bossa novas and the obligatory transcription of Rodrigo's Concierto de Aranjuezamong the most beautiful on record, in my opinion. It's one of the best-sounding MJQ records, but when I bought the LP I didn't know the great recording engineer Ray Hall from Robert Halland if you don't know Robert Hall, think Men's Warehouse ca 1964. Hall, best known among audiophiles for his jazz work for RCA during the Living Stereo era, engineered this disc.
The tapes are 50 years old, and the CD transfer sounds dark and closed-in compared to the original LP, which offers so much more detail and genuine air that it's not funny. Unfortunately, the vinyl is also noisy, and has been since day one: Atlantic vinyl back then just wasn't very quiet. There's also distortion on the dynamic peaks not heard on the CDbut Almeida is often buried on CD; he's fully present throughout the vinyl version.
The RM-200 Mk.II's rendering of this album in either format was masterful. Even at very low volume, the nylon strings of Almeida's acoustic guitar were clearly identifiable as such, his finger plucks delicately but decisively drawn. The vibes shimmered convincingly, and John Lewis's somewhat darkly recorded piano didn't merge with Percy Heath's bass into dark sonic muck. A tube amp with less bottom-end control than the Music Reference, or more sluggish attack, or with less than linear frequency response would probably have turned this recording into goo.
Tone, Space, and Dynamics
The RM-200 Mk.II's tonal character was as neutral as that of any tube amp I've heard. As with the VTL MB-450 Series III Signature monoblocks that I reviewed last April, the less expensive and less powerful Music Reference's top-end extension was airy, extended, and expansive, with a clean, precise attack, but minus the etch, grain, and glare some solid-state amps exhibit, or the compensatory softness sometimes added to avoid the opposite problems. The bottom was as previously described, while the mids were properly but not overly lush. The only obvious tonal coloration was a slight hint of warmth in the upper bass that never poured syrup on the picture but occasionally added a pleasing fullness.
Soundstaging and imaging three-dimensionality were two of the Music Reference's strong suits. Stage depth was pronounced, with images appearing well in front of the speakers and, when appropriate, extending well back.
A two-LP (180gm) reissue of Carole King's The Carnegie Hall Concert: June 18, 1971 (Epic/Legacy/Mobile Fidelity Sound Lab MFSL 2-351) arrived today, and this amp nailed the grit and edge in King's voice, the "whiteness" of the hall's direct sound picked up by the close miking of her voice, the cushion of the first reflections and their delayed "bounce" well back in the pictureas well as, about three-quarters of the way into the concert, the woody warmth and three-dimensionality of the onstage string section to King's side.
The RM-200 Mk.II's impressively low noise floor and its excellent characteristics of sustain and decay helped produce superb microdynamics and an overall picture that was vibrant and three-dimensionally solid. While its macrodynamic performance was very good, it's not surprising that this 100-watter couldn't express the huge orchestral explosions that larger, more powerful solid-state amps can manageand as good as its bass was, if you want maximum punch and the ultimate in bass drive and solidity, solid-state is the only way to go, even if it often comes at the expense of textural delicacy.
Still, as I said, when the RM-200 Mk.II was in the system, I wanted for nothingand for $4200, that's something!
Those who complain of the ever-increasing prices of high-performance audio gear need only look at the Music Reference RM-200 Mk.II. It provides high performance, high build quality, high reliability, and, I'm sure, great measurementsall at a low price, considering how much honest musical enjoyment it makes possible. And it's made in America.
It costs $4200. If that's your idea of "expensive," well, regardless of what you can afford, you're in the wrong hobby. It has no blue LEDs, but you can't have everything.