Translation: Krzysztof Kalinkowski

The Katowice based company RCM was founded based on the belief, that also in Poland a product can be built, which will be able to compete with the more expensive world class products on equal terms in the field of sound and manufacturing quality. I am talking about world class products, because the first commercially available product, the integrated amplifier Bonasus (Product of the Year 2006) was not cheap. It showed however, that the assumptions were fulfilled easily. The device was a tube amplifier, as the folks from Katowice are tube lovers. Tube and vinyl lovers. So the next brain child is a gramophone preamplifier naturally. However unexpectedly it is a solid state device, and even worse one based on the cursed, three times damned, integrated circuits. That explains the IC in the name of the product. But when I listened to it for the first time, during the presentation in the Chillout Studio, I did not know about that, and even if somebody mentioned this to me, then I forgot about it. And maybe this was good, because the sound, although very detailed, with good dynamics, had also a nice timbre, like from a tube device. So it was just a matter of time that this product fell into my hands.


The preamplifier from the company RCM Audio was my listening companion for quite long time. When I connected it to my system, it did not want to get disconnected. Although in the meantime many other preamplifiers came through my hands, including better ones (about that in a moment) so I did hear the assets and shortcomings of this device, it had no real meaning for me, because this all made me trust the Sensor. I know that this is anthropomorphism, putting human characteristics on a non-human device, but being engaged into something, having a passion, such kind of projection is natural and automatic. So I repeat that I trusted the Katowice made preamplifier quickly.

In general the sound of the Sensor can be described as ultra-clean, with a splendid, fleshy, strong bass and a resolving, completely not overdrawn treble. Although some tendencies can be identified after listening longer, but the whole time we know that we deal with SOMETHING. The first disc I listened to with this preamplifier was the vinyl version of Love The Beatles (Apple/EMI, 397 808, 180 g LP). Because I described the CCD+DVD-A version of this recording (review HERE), where the “dense” DVD-Audio 24/96 disc played on the Luxman DU-50 sounded much better than the CD version, so I more or less knew what to expect. But it turned out that I did not know anything. It turned out, that again a vinyl version of a new issue is much better than the digital version. That was the case with Depeche Mode discs, with the latest David Gilmour and Kate Bush. Maybe the problem lies in the copyright protection (all discs are in the CCD version), but maybe the master for the vinyl is done in a different way. Regardless where the truth is, a fact is a fact. The Beatles on vinyl sound incredibly more organic, saturated, without the annoying treble, that was there in the digital version, regardless of the format. And the RCM showed it perfectly. I mentioned its transparency and the precise drawing, and such statements are often a prelude to cold and boney sound. Probably there is some truth in this, but it is related to other products. Here the mentioned characteristics allowed to phenomenally reproduce the organic and warm vinyl Love sound. This made me listen many times to the D side with the opening piece “While My Guitar Gently Weeps”. The beginning is just a guitar and a voice – shown brilliantly, with good drawing and very nicely built harmonics. Vividness was also splendid, that can be achieved by laying back the treble – we have a warm, little resolved sound then – or, like it was done here, by as little intrusion in that what is playing, by as little distortion as possible, distortion that translates into slowing down of the sound or brightening and hardening of it.

The Beatles disc was a good introduction to the listening session, but the pulse of the brilliantly recorded disc Tour de France of Kraftwerk (EMI, 591 708, 2x180 g LP), just pushed me in the sofa I was sitting on. I ordered the disc while being enchanted by another disc Minimum-Maximum played during the RCM presentation in the Chillout Studio shop (reportage HERE) and I was not mistaken. Kraftwerk has their new discs pressed in heavy vinyl and with very broad grooves. That is the reason that two discs are used although the material could be recorded on just one vinyl. This gives an ingeniously saturated sound with very good bass. Both those elements were shown brilliantly by the RCM. I do not hesitate to say so, because only the Manley Steelhead was able to play it in a similar way. Very, very rarely a phono preamplifier can discipline the low frequency range not losing its timbre and in addition play everything with the dynamics like the RCM does. I want to keep my reason, and not waste words, but keeping some distance, I would say, that this sub-range is played that well by only one device I’ve heard until now – the mentioned Manley, costing 35000zł. Here we have no doubts what is on the disc, how sounds the gramophone, etc. With the RCM the Violator Depeche Mode (Mute, DMLP7, 180 g LP), and especially the opening piece “World In My Eyes”, with the bass guitar (or its electronic equivalent) was superb. All those people that think that vinyl means softening, should listen to the Sensor with a good turntable. Here is a kind of softness but it is not a washing out of the sound, but its natural timbre. In the normal world nothing stings us in the ears, and for sure not a bass guitar or a contrabass. The instruments can sound in a very dense, physical way, if they were recorded like that, but a good system will show that this is the issue of the recording, and not of the system or format. So the difference between the phenomenal discs of Yamamoto, Tsuyoshi Trio Misty (Three Blind Mice/Cisco Music, TBM-30-45, 2 x 45 rpm, 180 g LP, #0080/1000) and Midnight Sugar (Three Blind Mice/Cisco Music, TBM-31-45, 2 x 45 rpm, 180 g LP, #0080/1000) – reviews HERE - were clear and undisputable. The first disc played with less bass but also with not that splendid piano. And on the piano in Midnight... one could appreciate how the preamplifier cares about the midrange. It is incredibly clear, dynamic and extremely clean. And there is no brightening there. And although the vocal from Violatora or the guitars from the original issue, from 1978, of the debut disc Dire Straits Dire Straits (Vertigo, 6360 162, LP) sometimes cut, but in both cases this is a shortcoming of the recording. The preamplifier did not mask it as well as the Accuphase preamplifier, but also did not emphasize it. It was just as it was.

I mentioned Accuphase. An optional extension card can be mounted inside their preamplifiers, including the DA-20, a RIAA preamplifier. The name “extension card” is misleading in this case, as this is a full fledged, powerful phono preamplifier, with two separate inputs – for example for a turntable with two arms – that costs almost 10000zł! For a card! If you would like to add to it a classy power supply and casing, then the full device – a phono preamp – would have to cost 30000-40000zł. So do not have the price mislead you. And I reached for the C-7810 with the AD-20 after the presentation I saw during the IFA 2007, prepared by “Audio” and “Stereoplay” (reportage HERE). There, to a very expensive system, composed of the JBL Project Everest DD66000 loudspeakers, converter and preamplifier – the reference surround processor Mark Levinson No 40 Media Console driving Krell amplification – the brilliant two part monoblocs Evolution One working in the bass section and the stereophonic EVO 402 for the treble, and as the source the Clearaudio Statement with a Goldfinger element the Accuphase C-7810 with the phono preamp card was used. And the sound of this system was really superb. Brilliant. So it was a natural thing to compare the Sensor with the mentioned card, especially as the C-7810 was readily available. And there was nothing to be ashamed of. Although the Accu treble was more vibrant, as if classy tubes would have been used (and it is a solid state device), and the midrange had a deep, dense timbre. But the dynamics and the bass contents, as well as the openness of the sound were better from the polish design. On the other hand, the depth of the sound as a whole, the ultimate resolution, was better with the Japanese. When the disc The Bassface Swing Trio Plays Gershwin (Stockfisch, SFR 357.8045.1, 180 g LP + SACD/CD) begins, we have for a moment the atmosphere of a small recording studio, with the noises and instrument sounds. With both preamps the feeling of “being there” was very strong, but the Accu presented a bit broader and more dense “tissue” between the performers. But when dynamic playing enters a few seconds later, the dynamic of the attack of the sound is shown better by the RCM. And so on, and so on. Similar impressions are when comparing to the Manley. But you have to remember, that both devices are five times as expensive as the Polish device, but when we fight, then let’s fight with the best. On the other hand, when we compare the timbre of the RCM with the Manley, then – surprisingly – Manley sounds with a tad colder timbre with not as perfectly led bass. This is a paradox, as the solid state Accuphase sounds warm and the tube Manley much colder. The RCM is much closer to the American than to the Japanese in this aspect.

The preamplifier of the Katowice based company RCM is something that does not happen often. Its price is not low, but only when dealing with budget components. If we talk about hi-end the price is more than acceptable. One has to spend much more money to surpass that what is offered by it. I am sure, that RCM will prepare something even better, but it will not happen tomorrow or over tomorrow, as the construction of the device took considerable amount of time. Thus the decision to buy the Sensor for my reference system.


The gramophone preamplifier Sensor Prelude IC is composed of two boxes with solid enclosures – one contains the main circuits and the other the power supply. The main unit is made from thick aluminum plates, painted black, except for the front panel from scratched aluminum. In the front panel, except for the screws, there only a logo and a green LED. There is more on the back. There is a pair of RCA inputs, a pair of RCA outputs and a pair of XLR outputs. Next to the inputs small switches are placed allowing for input impedance adjustment – 1000-400-200-50-20 and 47k for MM elements. We can also set the input sensitivity – 0.3-0.4-0.6-0.9-1.4-2.5-5mV. A unique ability of the Sensor is that we get 2V on the output, so a value comparable with a CD. The amplification is 52 to 76dB. So there should be no problems in driving any line preamplifier. It must be said, that manipulating the switches is not easy (it was similar with the Edgar TP-305preamplifier) and in the more expensive device like the Manley it is helpful to have the controls brought out on the front panel. But if we set them only from time to time, then there should be no problem. Far to the right we have also a grounding pin and a metal, male DIN socket, to plug in the power supply.

The inside is not very crowded. Near the front panel we have the power supply (without the transformer), separate for the left and the right channel. As we can read in the company materials the power supply is symmetrical. The capacities are not big, especially if we compare to that what can be found in ASR devices. But the people from RCM claim, that the capacities were especially adjusted for this application. The amplification circuits are mounted on two high quality PCBs – each channel on its own PCB. The amplification is handled by ICs from Burr-Brown, the INA217 on the input and the OPA2134 on the output. Between those there is a two stage passive correction circuitry, with metalized resistors and polypropylene capacitors. The resistors are hand picked, so the RIAA correction precision should be 0.3dB in the 20Hz-20kHz frequency range. There is no low pass filter to filter out turntable vibration, just to not allow for any phase distortion in the bass range. On the output we find another IC – the SSM2142 Analog Devices – a so called line buffer, a chip used for driving long symmetrical signal lines. This allows to place the preamplifier near the turntable and use a long interconnect to connect to an amplifier near the speakers. Attention is drawn by the mass leads that convey the mass from all sections to one point on the bottom of the device. The power supply is a separate black varnished box. Inside there is an AC filter and a small classic EI transformer. It connects to the main unit by means of a fairly thick cable with a writhed, solid DIN plug. I am curious how the newest, revolutionary plug of this kind prepared by Naim would work in this place. As the information on the nameplate on the bottom of the device states, the man responsible for the design is called Yaxa.

Technical data (according to manufacturer):
Input sensitivity: 0.3 - 5 mV (adjustable)
Sensitivity adjustment: 0.3 – 0.4 – 0.6 – 0.9 – 1.4 – 2.5 - 5mV 
Amplification: 52 - 76 dB (2Vrms output)
Input impedance: 20 - 47k
Impedance adjustment: 20Ω – 50Ω – 200Ω – 400Ω – 1kΩ – 47kΩ
Input capacitance: 150pF
Input mode: symmetrical – non-symmetrical
input: RCA
THD: 0.01%
S/N: 85dB
RIAA linearity: +/-0.3 dB (20Hz-20kHz)
Output impedance: 70
Outputs: XLR, RCA
Nominal output power: 2Vrms
Maximum output power: 8Vrms
Dimensions: 214 x 214 x 75mm – preamplifier / 120 x 65 x 160mm – power supply
Weight: 2 kg. – preamplifier / 1.7 kg. – power supply
Power consumption: max. 5 W


Price: 6000 zł

Distribution: RCM


RCM s.c.
ul. Matejki 4
40-077 Katowice

Tel: 032 / 206-40-16
032 / 201-40-96
Fax: 032 / 253-71-88
e-mail: rcm@rcm.com.pl



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