REVIEW: RCM SENSOR 2 PHONO AMPLIFIER

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by Peter Familari

2 months ago

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REVIEW: RCM SENSOR 2 PHONO AMPLIFIER

Prefer to read the PDF? Click below to download our review of the RCM Audio Sensor 2 Phono Amplifier. Otherwise, read on.

RCM Sensor 2 Phono Amplifier Review

It would be churlish not to admit the advances Digital sound quality has accrued.

But this good news should be tempered by a couple of insights: it’s taken digital more than 30 years to reach a more than acceptable level of sound quality and no, in my opinion, digital is still not a match for analogue.

Yes, digital is largely noise free, has constant pitch and downloads are imperishable and theoretically should last forever. CDs and SACDs have the same positives but the discs have to be carefully handled and stored with care.

Either way, downloads or silver discs are more robust than vinyl which has to be played, handled and stored with exacting amounts of attention. LPs hate dust, finger smears and damaged stylii.

Play an LP track several times in 24 hours and the groove distorts. Which leads any sane music lover to the question: why would you bother with analogue or pay $3999 just for a phono stage, albeit a phono stage the calibre of the RCM Audio Sensor 2?

Especially when playing a download, or disc ad infinitum doesn’t involve a skerrick of wear and tear.

The answer, is as close as the nearest Rega 1 turntable. Or for that matter a budget Music Hall, ProJect or Thorens model equipped with a decent tonearm and a nicely built but inexpensive phono cartridge.

Slip an LP on these platters and assuming the turntable is linked to a nice sounding budget amplifier and well-credentialed pair of inexpensive speakers, the only reason to prefer analogue over digital is sound quality.

Compared to a CD player priced ten times more than a Rega 1 or the best hi-res download you can muster, analogue sounds more like the real thing.

So much so, I don’t attempt to force my opinion on other people or try to change their opinions about the merits of digital. In fact, I no longer debate the virtues of analogue vis-à-vis digital with non-analogue devotees.

There’s no point. While it’s true Audio is a broad church and one I attend religiously. But it’s not a church on whose behalf I’d care to proselytise.

While at heart I remain what I always was, an anachrophile, I’m not a Luddite. I accept digital as a triumph of convenience over sound quality, and I have no qualms exploiting digital’s user-friendliness.

I adore my Audio Research Reference CD 7 CD player and love the irony of its digital circuitry sharing valve electronics. I can play fave CDs virtually on endless repeat while I pound the keyboard writing for StereoNET, 6Moons and TED magazine amongst other publications, for a meagre living.

I’ve had to embrace digital especially for the pages of 6moons not because I was forced to. Nothing could be further from the truth. 6Moons, like StereoNET has an enlightened editorial policy. Neither tells me what to write.

But I would have been in denial if I had ignored digital developments. The technology and formats are all around us, and the marriage of computers with audio is a fait accompli.

These days along with CD and vinyl, I use a Mac laptop loaded with Tidal software and storing a library of about 1500 tracks with my large “R” reference system, as well as the small “R” reference systems that populate the household.

Almost every night I dip into the Tidal library using an iPhone 6 linked to a Chord Electronics Mojo and a pair of Grado RS2s.

If I were single, as those who know me would attest, I’d have a Linn LP12 with Ittok and Karma cartridge running into a Radford STA25 amplifier and Elektra preamp plus a pair of Tiny Harbeth or Rogers LS35/A 65th anniversary speakers in my bedroom.

My wife, a fellow travelling audiophile, who for my birthdays would hunt down Ortofon SPUs and send them to John and Brian Garrott for repair when they were in Melbourne, would gladly allow me the luxury of a kosher hi-fi system in our bedroom. But only if the room was large enough which it isn’t. And only if she didn’t need a long kip to survive teaching primary kids Mondays to Fridays.

So I make do with the phone, the Mojo and the Grados.

Truth is, I revel in the ability to dip into musical styles and new music at will. Anti-digital, I’m surely not.

But as surely as I embrace the digital universe professionally and personally, there are limits. And I know when I’ve reached the boundary between the merely convenient and that which is verily soul enriching.

My personal avenue to musical bliss is as simple as shuffling to my turntable and going through a much-loved ritual. The vinyl record is removed carefully from its precious album cover, the disc placed on the platter and cleaned with a carbon fibre record brush, the stylus cleaned with a Discwasher brush I’ve had forever, and finally the moment arrives.

With the record clamp in place I power the turntable up, adjust the volume level and sit back in my chair as the sound of analogue music washes over me. Before I hear a note, I already know what to expect. No matter the genre, be it AC/DC or a delicate string quartet, I already anticipate a musical performance that draws me into the heart of the music.

The point is, heaps of cash isn’t required for this qualitative listening experience. Which is why I labour the notion of budget models the calibre of a Music Hall, Rega, Project or Thorens.

But just as surely, as you move up the audio hierarchy and away from the budget vinyl spinners and gravitate to the mid-priced and higher-end models, analogue’s supremacy over digital hits you fairly between the ears. And it can’t be ignored.

At these levels the turntable, tonearm and cartridge are more than likely pedigree models. Which means their owners will require a commensurate phono stage if the accompanying electronics don’t already have one built into the circuit.

For those that don’t, the news is fairly good. Decent phono preamplifiers abound. Great ones are much thinner on the ground. Having said that, it’s also fair to point out the adage about how the excellent is the enemy of the merely good, and if this holds true and I think it does, you can expect excellent phono preamplifiers to be much rarer than merely “good” ones.

RCM Sensor2

The RCM Sensor 2 has been used constantly for personal listening pleasure as well as my professional reviewing work for a several weeks. I can’t say I’ve listened to all its rivals. With this caveat, what I can share is my admiration for a phono stage so compellingly musical, I really haven’t the urge to want to go looking for anything better.

The RCM Sensor 2 phono preamplifier is the successor to the well-regarded Sensor Prelude IC that was still available in 2012.

A close friend owns the Prelude IC and we’ve shared many listening sessions hearing it weave its talents through his Krell Electronics, Martin Logan Sequels and a VPI turntable equipped with an SME IV tone arm and Lyra Delos cartridge.

A loan was arranged so I could compare the older RCM with the newbie model.

Warwick Fremantle, CEO of Pure Music Group, the company that distributes RCM Audio in Australia explained the updates the Sensor 2 has which the Prelude IC does not.

The 2’s power supply is much bigger and it outputs DC rather than AC. Current is more stable in the 2 because RCM have put more capacitors into the power supply. It has higher-grade resistors as well as capacitors, and RCM has done a lot of house-work internally and the circuitry is now more sophisticated and the layout is more superior than the Prelude IC.

Comparing the new RCM with the old revealed the Sensor 2 has a larger range of loading settings and users can choose from 20, 30, 50, 100, 200, 400, 1000 and 47KOhms. Adjustable gain is also in the sensible range of 52 to 76 dB.

With fully balanced circuitry, inputs are RCA only with a selectable switch for the choice of balanced or single ended mode depending on how your phono cable has been wired. This enables the user to optimise the Sensor 2 to achieve the lowest possible noise floor. The outputs comprise single pairs of RCA and XLR.

RCM Audio Sensor2 Internal

The input sensitivity is said to be 0.3 to 5 mV and this is adjustable via seven settings. Input impedance ranges from 20 Ohm to 47 kOhms. Input capacitance is 150 pF and Total Harmonic Distortion is said to measure a negligible 0.01 per cent at 1 kHz. Signal to Noise ratio is 85 dB used with the lowest gain setting. Output impedance is 70 Ohm, nominal output 2 V rms while maximum output yields 8 V rms.

Build quality inside and out is what you’d expect at the price and this extended to the finish of the low-resonance metal cases that delightfully have no visible screws.

Worthwhile options and upgrades include gold Furutech RCA inputs, RCA and XLR outputs. The IEC power socket is also equipped with a Furutech fuse. This optional upgrade adds $500 to the $3999 price of the Sensor 2 and was included on our review sample.

Performance

The gear used with both new and old RCMs comprised an SME 20/2 turntable with SME V tonearm, Bloom 3 and Original Kiseki Purple Heart cartridges.

Electronics comprised the Audio Research LS17SE pre-amplifier and Reference 75 power amplifier. Speakers used were Wilson Audio Sashas.

The track chosen to begin the audition is as old as Methuselah and as timeless and beguiling as the Sphinx. Hoagy Carmichael composed Stardust in 1927 and the lyrics by Michael Parish were added in 1929.

Considered the most perfect song ever penned, though some would include George Harrison’s composition called Something In The Way She Moves and others The Beach Boys’, God Only Knows. I’ll put my money on Stardust.

Described as a song about a song about love, Stardust has been recorded by a horde of artists. Though I adore the longer, more complete interpretation by Nat King Cole, no version has the heart-string pulling power of Frank Sinatra’s short version that runs to only 2minutes and 49 seconds on the album, Sinatra and Strings.

While the aforementioned string section of the backing orchestra can screech a trifle thanks to the age of the master tape used for this repressing, there’s no mistaking the genius of Sinatra at the peak of his craft.

Reproducing this song in the way Sinatra wants you to hear it requires an audio system that doesn’t have to cost a fortune. But what it must do is respond intuitively to Sinatra’s timing, phrasing and musical ambience.

With the Sensor 2 and either Bloom 3 or Purple Heart in the system, the equipment retreated and so did Sinatra.

What was left was an avenue into the spiritual heart of the music, unencumbered by singer, orchestra or audio equipment.

With the older Prelude IC, Stardust became a different song. It was still a powerful experience, but somehow in ways so subtle and almost imperceptible, the avenue closed leaving the listener merely an observer of the singer and the orchestra rather than a participant in the musical drama.

Without the Sensor 2 for comparison and as a standalone phono stage, the Prelude IC is no dullard. It’s musical, detailed, times well and presents well recorded music with plenty of width, depth and height.

Switching back to the Sensor 2 was like going from a watercolour landscape to one crafted in oil, from mineral water to wine. Intoxicating stuff.

So intoxicating it was time to spin Pink Floyd’s “Atom Heart Mother’’ and head (pardon the pun) to track 5, Alan’s Psychedelic Breakfast. And sure enough, the Sensor 2 opened up the heart of this music, disbelief was suspended and the imagination took over.

It was akin to being in Alan’s kitchen watching him fill the kettle, strike a match and light the gas stove. The sound of bacon sizzling was startling.

Pacier and less hallucinatory, The Blue Nile’s self titled album played using the Purple Heart sounded so assured, I played through the entire side of the LP before the realization arrived that it was time to return the arm to its rest.

Van Morrison’s Ballerina from the Album Astral Weeks had an ethereal sheen so enjoyable, I broke the cardinal rule and replayed this track three times in succession without a 24-hour respite, and probably distorted the groove.

Conclusion

The RCM Audio Sensor 2 was used to playback a mountain load of albums. Dylan, Howling Wolf, Fink, Stevie Wonder, The Shirelles and plenty of Joni Mitchell. It was early the next morning that the system was reluctantly switched off.

Without hearing anywhere near enough phono stages to describe the RCM Sensor 2 the “best at its price’’, that accolade will have to stay in neutral.

What I can tell you is that importer, Warwick Freemantle swears once auditioned, the Sensor 2 is seldom returned. I kind of feel the same way and if I can find the four large to make it mine, it’ll be a keeper.

The RCM Audio Sensor 2 Phono Preamplifier is available now starting at $3999 RRP.

RCM Audio is available from Specialist Retailers.

Peter Familari's avatar

Written by:

Peter Familari

One of the veterans of the Australian HiFi industry, if there's a speaker he's likely heard it or owned it at some point in his career. Peter was formerly the audio-video editor of the Herald Sun for over two decades.

Posted in: Hi-Fi
Tags: rcm audio  pure music group 

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