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Reviewer: Srajan Ebaen
Source: Zanden Audio Model 2000P/5000S
Preamp/Integrated: ModWright SWL 9.0SE; Music First Audio; Hyperion Sound BEC-P25T
Amp: 2 x Audiosector Patek SE; Yamamoto A-08S; Canary Audio CA-308s; FirstWatt F3 [on review]
Speakers: Zu Cable Definition Mk 1.5 Pro version with Rane PEQ-55; Gallo Reference 3
Cables: Zanden Audio proprietary I²S cable, Zu Cable Varial and Ibis, Zu Cable Birth on Definitions; Stealth Audio Cable Indra, MetaCarbon & NanoFiber [on loan]; SilverFi interconnects; Crystal Cable Reference power cords; ZCable Hurricane power cords on both conditioners
Stands: 1 x Grand Prix Audio Monaco four-tier
Powerline conditioning: 2 x Walker Audio Velocitor S
Sundry accessories: GPA Formula Carbon/Kevlar shelf for transport; GPA Apex footers underneath stand, DAC and amp; Walker Audio SST on all connections; Walker Audio Vivid CD cleaner; Furutech RD-2 CD demagnetizer; WorldPower cryo'd Hubbell wall sockets
Room size: 30' w x 18' d x 10' h [sloping ceiling] in long-wall setup in one half, with open adjoining living room for a total of ca.1000 squ.ft floor plan
Review Component Retail: $1,995
Roger Modjeski -- who tends to not make waves but rather, work quietly in the background and as a consultant to numerous makers (think Counterpoint SA-4) -- has of late made waves with the announcement of his $6,000 limited edition RM-245 amplifier. As a single-ended amp, it's a first for Music Reference. By outputting a claimed 5 watts from a direct-heated 45 valve, it's another first in general (that's more than double the norm) but certainly not a first for Modjeski whose amps always offer far more power than their tube complement suggests possible. This leads sceptics to write off these power claims: "Marketing bravado! Engineering impossibility!" Yet RM's reputation for both brilliance and forcefully held opinion -- it's clear whose initials these are in the amps' nomenclatures -- usually means that naysayers keep their opinions to themselves. Those careless enough to voice them publicly enjoy quite the beating especially (but not exclusively so) if they lack the bona fide EE credentials and real-world experience of their adversary.
John Atkinson's 2002 measurements of Modjeski's still current 1998 flagship, the 100wpc fully differential RM-200 outfitted with 2 x KT88s per side, confirmed the maker's power specs. Michael Fremer, the reviewer, called the Music Reference his favorite amp out of a quartet he'd reviewed over a stretch of 6 months -- this included the Kora Cosmos and Hovland Sapphire valve amps -- and surprisingly similar to but with a superior midrange than his reference at the time, the Musical Fidelity Nu-Vista 300. And while JA criticized some out-of-band distortion behavior in his commentary accompanying the test bench results, Modjeski's manufacturer's reply makes clear that he designs for load invariance and stability in the audible spectrum. It further makes clear that when given the opportunity, Modjeski is rather intolerant of and outspoken about the widespread design inaptitude he perceives rampant especially in the valve amp sector; and equally the willingness of consumers to purchase such over-priced "accidents waiting to happen".
Sharing California's sunny Santa Barbara with audio legends Bascom King and Kavi Alexander, Roger Modjeski is well-known for pioneering computer testing for bias and transconductance/gain tube matching. He personally wrote the sophisticated software program that takes over 200 individual measurements on 128 tubes simultaneously. RAM Tube Works, the valve testing/sales arm of his company, continues to this day to supply the professional industry as well as hobbyists with warrantied, tightly tested and matched glass.
George Lenz, a NYC investment banker and VP of Product Development & Marketing for Roger, explained how Music Reference winds its own transformers. As iron aficionados know full well, the quality of output trannies in transformer-coupled valve amps is a most vital contributor to their sonic performance. It's why Art Audio amps for example enjoy their special renown. They all use unconventional custom transformers hand-wound by British old-timer Peter Chappell who also works with Tom Evans in a similar capacity. Lenz explained that bringing this critical element in-house means not only better performance -- Modjeski literally hand-tunes his iron to a given circuit rather than deal with off-the-shelf units to require that the circuit compensate for the transformer -- but also guarantees a significant pricing advantage. After all, transformers tend to be the second costliest item in any tube amp after the chassis (unless a particular design goes with a modest enclosure and unapologetically sinks the money into where it matters - sonically). Making superior application-specific transformers in-house rather than outsourcing them cuts down build costs.
During the course of our "getting to know" conversation, George complimented us on our site and divulged that Music Reference has a 300-watt monster amp on the drawing board and that the limited edition RM-245 with its meter and extreme bias flexibility will soon be joined by a stripped-down version for a significantly lower retail. Then he asked whether I'd like to review their new RM-10 MkII. That's a 35/70-watt stereo/mono amp of diminutive physical proportions, a very sane asking price of $1,995, transformer/resistor/terminal refinements over the original version and 6BQ5/EL84s for power tubes. I instantly said yes for two reasons. First -- and as Almarro, Decware, Manley Labs and Tom Evans in particular have already proven -- the li'l EL84 tube is one amazing valve when implemented properly. Secondly, Pat McGinty of now defunct Meadowlark Audio owned an RM-200 during my time as his sales manager and relied on it extensively during the R&D period of the original Heron. Pat used a very well-stocked test bench and both technically and sonically had nothing but superlative compliments for that amplifier. All things considered, reviewing its baby brother now was thus a natural and overdue affair, particularly seeing that its pricing and design brief nicely coincide with my ongoing Realsization adventures.
With frequency response given as 8 - 50,000Hz -3dB, the amp is said to exhibit less than 1% of THD from 50 - 10,000Hz up to full rated power (the latter a critical and very impressive qualifier that's either completely missing in competitor's disclosures or given as a number at a fixed frequency and on an output voltage that's a fraction of full power). At typical usage, THD is referenced as 0.08% into 16 watts and 0.06% at 10 watts, with attendant hum level of < 0.25 millivolts and noise/hiss at 40-80 microvolts. For extremely noise-critical applications such as super high-sensitivity speakers, the maker suggests the use of his SLN (super low noise) 12AX7 driver tubes. Input sensitivity is 950 millivolts, meaning that even my half-the-industry-standard 1V-out Zanden Model 5000 Signature DAC would drive this amp to full output, no active preamp required.
At 14 lbs, the RM-10 MkII is a lightweight that makes no silly demands on chiropractor bills, shelves or flooring. Eschewing printed circuit boards, each amp is done up by hand in point-to-point wiring and claimed "unconditionally stable". This means that your only consideration is requisite max power. If you don't exceed 35-watt listening peaks, your speakers will be copasetic. For additional headroom -- if required or desired -- you can bridge the RM-10 for 70 watts of monaural power. Inputs are gold-plated Tiffany RCAs on 100Kohm input impedance, outputs half-inch solid-brass hex-head posts on 8- and 4-ohm secondaries. "In a world where 17 watts from a pair of 6BQ5 was considered the limit, designer Roger A. Modjeski has endowed the RM-10 with 35 watts from the very same pair of tubes. More good news is found in the eco-friendly nature of the RM-10 which uses only 70 watts of precious electricity at idle. This convergence of economy and efficiency is further evidenced by output tube life that exceeds 10,000 hours." Retubing with RAM-tested valves will cost between $120 to $240 depending on make of EL84 (Yugoslav EI or Russian Sovtek) and test grade of 12AX7s. So even in the 'worst-case scenario, to retube the entire amp will cost less than one exotic direct-heated output triode in my Yamamoto SET. Can you say halleluja and real-world practical? That's why I'm curious about this amp.