RCM Audio Sensor MC/MM phono preamplifier review

With the recent revival of the vinyl and analog playback in general the quest for suitable phono stages become much more focused and of a critical appeal. Audiophiles, music lovers and vinyl enthusiasts these days demands and search for a products, that would bring them them best performance and value for their investment. We’re living in the interesting times. Its an era of the high-end! No matter, what the public propaganda might say, I’m repetitively declaring how its actually the best time to be in high-end audio. As manufacture, consumer and non the less as reviewer. There was never so much gear to choose from in the history of the high-end audio and if you’ll do your homework profoundly the path to the satisfying purchase can be ensured these day. This is a fact!

Vinyl is dead!? Not at all. Companies like Project Audio or Clearaudio cannot produce enough turntables per month to meet the demands. Similar thing happens on the West side with VPI, Kronos etc. and on the east side TechDas etc. Even the all new products like Audio Union Helix turntable is preordered and backlogged. High-End audio might still be a niche market, yet taking into the consideration the global sphere, its not that small at all. 

In past few years many companies revived or newly introduced their phono stages to the market. Its not only interesting on the consumer side. The market situation reflects the growing pace for the manufacturers in the same way. In the era of globalization vast market can ensure viability even for the small manufacturers. 

And these days this is almost as a rule a win win situation for the both sides. Small, boutique manufacturers are doing their best in designing really stand out products that will enthuse the consumer side and manufacturers are striving to bring the best for the buck. This is a healthy business model, that will work out on the long run and its already proved to be fissionable. Thumbs up!


RCM Audio SENSOR 2 phono preamplifier pushes the performance of it's predecessors even further. It has evolved from company past experiences and attempts to improve the parameters of a device as create most demanding performance. SENSOR 2 was designed and manufactured with clear goal. RCM team wanted to achieve the maximum possible results with available resources and technology and strictly choose built in electronic parts. Every circuit decision was based on the past experiences and listening. In this way they could utilize optimal results while retaining attractive price point.  

Just like the first version, SENSOR 2 stands out from other phono preamplifiers with it’s high output level. RCM Audio believes, that at least 1 volt output is of utmosts importance and necessary to retain a high-quality sound. High-performance, high quality sounds is of course driven by many factors including the higher level signal preference of the input step. 

The ideal solution would be to increase the output to 2 volts. Yes, this brings us to the level output of the typical CD players. Doing that imposes some of the high requirements for the entire device. MC cartridges with output of 0,3mV requires the signal to be amplified by 76dB – over 6300 times! Now, thats not your entry level stuff to work with!

Ask any matured high-end audio designer regarding the importance of the power supply. You’ll always get the same answer! Most important! Its no different with SENSOR2 phono preamplifier. It features a symmetrical power supply that is constructed to minimize signal distortion. Great care has been paid to selecting the capacitors in the filtering circuit and lowering the output impedance of the amplifier. The decision to separate the power transformer from the rest of the circuit and adding its own chassis also affects the sound in a grand way. The most important upgrades and changes were implemented with the main power supply and the operational amplifier. The first part consists of a transformer, bridge and first step of stabilization. The second step is separated and found in the preamplifier chassis. 

The chassis of the amplifier and power supply are made of hollow rectangular cross-section tube that drastically reduce flexing. All elements are made from non-magnetic materials.

This extensive upgrade results in increased dynamics, lower noise floor and a larger sound stage both in width and depth. 


SENSOR2 allows you to select between single-ended or balanced outputs. The signal coming from the cartridge is symmetrical, which enables an appropriate configuration of the input to widen it’s dynamics ranges while limiting the noise. RCM Audio comment: Why should you fix what’s not broken? 

Setting the load impedance is done via the switches on the back of the device. SENSOR2 features an 8-way switch that allows more options and help with much more precise setup of the phono preamplifier. Back plate also host the switches that allows the gain setup and let you choose the output stage mode (single-ended or balanced). 

SENSOR 2 amplification is handled by selected integrated circuit, and RIAA correction is performed by a two-step passive system with low-noise resistors and polypropylene capacitors. To assure precise signal correction every element of the filter system is measured and hand-picked, which results in signal fluctuations of below 0,3dB in the 20Hz to 20kHz range. 


RCM Audio SENSOR 2 phono preamplifier is a straight shooter and no brainer to operate. Its shows, that they know initially what they want to do and how the preamplifier should work in the real world operations.

I’ve tried SENSOR 2 with both MM and MC cartridges and results were more then inspiring on the both ends. The role of MM carries were given to more affordable AT and Ortofon cartridges for old vinyl and Nagaoka for the mint and latest analog black beauties. On the MC side I’ve paired the SENSOR 2 with my precious Takeda San cartridge. 

There is still ongoing “battle” between MM and MC camps of followers and they can get quite fanatical to defend their strong beliefs. I’m trying to level on the plane of sanity (if thats even possible in high-end audio) and capture the benefits of the both worlds. They are both capable in their own yet with quite a different flavor…

MM cartridges can come close to the sound of high output MC devices or even surpass some of them. For many setups, this is  the best and least complicated way to go in reaching the good and great sound. 

Now, when it comes to the reproduction of the signal coming from  MC, dealings with the lower gain cartridges become more complex and supreme delicate. There is no easy way to design a proper cheap MC phono preamplifier without sacrificing the performance. Sadly even some of the quite expensive phono preamplifiers cannot bring the level of analog performance needed to be there for the given price. As I’ve written many times before, designing a great sounding MC preamplifier is an art on itself. It cannot be done quickly, lightly and rushed. 

These days any DIY’er or skilled electronic designer can create a MC phono preamplifier with inspiring low level noise specs. And thats about it! Now, with bringing down the noise the as a rule the soul of the music is being taken away. There is no simple remedy to deal with it and this is where the skilled mindset comes forward. 


Simple, straightforward and understated. There is no unneeded abundance of aesthetic fireworks on the front place. Just resolving RCM Audio logo on the left, green led in the middle of the front panel and SENSOR 2 name on the lower right side. All of what’s important is hidden under the “hood” and on the back side.  


Tone, timbre and color. First and foremost important attributes for me to judge any high-end audio components. With analog front ends this becomes even more hard pressed as they offers an intricate way of presenting the music. 

Despite the fast forward pace and rise of the digital audio, in general it’s still lacking some of the attributes that great analog setup can provide. Along the tone, timbre, color; three dimensionality, sense of the space and that special feeling of the way the real music sounds its always closer to reality with vinyl and analog in general then with digital audio. What to talk about the reel to reel master tapes. Completely different universe.  

As usually I’ve pulled out my trustworthy arsenal of trusty vinyl references. I know the music material well, its in my blood and mind storage. Here the critical journey begins and reaching up to the status of high-end audio needs a specific set of rules must to be met. 

SENSOR 2 is designed differently and in the right direction. It clearly shows what was the preferred goal of RCM Audio team and it came a real positive surprise for a change. SENSOR 2 speaks for itself and can be quickly distinguished for its particular and distinguished sound impact. It plays music boldly and involving. SENSOR 2 is inspiring to listen and great to see the RCM Audio dedication into pursuing the great sound. 

Like all companies, clearly, RCM Audio is following the business model. Still I love when companies are pursuing the sound first and try to worry about the price later on as its not easy getting up to the level of such performance, especially at this price point and here SENSOR 2 is more then worthy of the highlight. 

In most cases the vinyl musical reproduction might lack in spatiality. Almost as a rule, that came as a precondition with the majority of tube based phono preamplifiers. Not exactly the case of tube technology being implemented, but more of a problem of the circuits and design choices. SENSOR 2 handled things more then well in this regards. I’m not talking about the overused pin-point jargon and other over chewed flóskula. The sense of the positioning and the richness of holographic presentation was stand out with this phono preamplifier. Relief layering, factual portrayal of instruments and voices was very good. Actually great. Things being conveyed via small signal flow form the cartridge is of most sensible nature. And especially with such high single output that SENSOR 2 is capable of, this can quickly result into a complete overflow and audible disaster. Here again the relativity comes to a healthy discussion. You cannot predetermine anything before actually testing it. This is why my job is both exciting and unpredicted. There are always true gems being out there and its more then worthy to explore the vast market daily, weekly, monthly and year after year. SENSOR 2 certainly belongs to such undiscovered gems. 


“Anyone familiar with Sensor Prelude will be most impressed when they hear the improvements in Sensor 2 that is delivered with only a modest increase in cost over the original. At it’s price point Sensor 2 is still exceptional value for money just like before, only better now.”

RCM Audio SENSOR 2 phono preamplifier is utilitarian and musically resolved in its performance. SENSOR 2 is clearly no quick exploiting business model product like many I’m to often stumbling upon these days. This particular preamplifier is well planned and design project resolved in a very refined and matured phono stage. SENSOR 2 offers heck a lot of analog enjoyment at the down to the earth pricing, allowing many of the audiophiles, music lovers and vinyl/analog enthusiasts to explore the endless vinyl universe via very transparent and musical imprint. 

In the era where everyone is in a rush to switch up to the luxury way of the pricing its great to encounter on products such as SENSOR 2 phono preamplifier. There is many way to pursue the high-end audio venture. There is always a way you want to get things done. RCM Audio team follows an applaudable path of high-performance and high quality sound at very reasonable pricing. For what it represent and what kind of the sound performance it brings at its giving price I’m wholeheartedly awarding it with Mono & Stereo Best Buy Award. 

I really wonder what the RCM Audio THERIAA phono stage is capable of as its born from SENSOR 2 R & D and designed as ultimate pursue.

Text: Matej Isak



Input RCA - Balanced and Unbalanced (selectable via switch)
Output: 1 pair balanced XLR
1 pair unbalanced RCA (single ended)
Input sensitivity: 0.3 - 5mV (selectable in 7 steps)
Gain: 52 - 76 dB (2 Vrms output at 1 kHz)
0,3 - 0,4 - 0,6 - 0,9 - 1,4 - 2,5 - 5 mV
Input impedance 20 - 47000 ohm (selectable in 8 steps)
20 -30 - 50 - 100 - 200 - 400 - 1000 - 47 000 ohm
Input capacitance: 150 pF
THD: 0,01% (1kHz)
RIAA linearity: +/-0,3dB (20Hz - 20kHz)
Nominal output: 2V rms.
Max. output level 8V rms.
Output impedance: 70 ohm
THD: 0,01% (1 kHz)
S/N: 85dB (lowest gain settings)
RIAA linearity: +/- 0,3dB (20Hz - 20kHz)
Dimensions: preamplifier 245 x 227 x 110 mm (without terminals)
power supply 122 x 230 x 70 mm (without terminals)
Weight: preamplifier 3,5 kg.
power supply 1,7kg.
Power consumption max. 17 W
Guarantee: Two year.
Options Gold Furutech RCA, XLR input and output sockets and IEC chassis socket with Furutech fuse.
Rhodium Furutech RCA, XLR input and output sockets and IEC chassis socket with Furutech fuse.


"RCM" S.C. Roger i Ewa Adamek
ul. Czarnieckiego 17
40-288 Katowice

+48 32 206 40 16
+48 32 201 40 96
+48 32 253 71 88