I have had many a phono preamp go through my audio
system – some were better, some worse, and some were pretty shit. Oh dear, I
do not mean to sound sexist, like saying, "I had many women..." So let us start
again: in my life I have used many phono preamps. No, that doesn’t sound much
better either – as if I had the same thing on my mind. I’ll try the
last time: I know (yeah, that sounds much better!) many phono preamps, probably over
a hundred-plus. I know many of them well or very well. Three of them have
been closest to what I mean by high-end: the Manley Steelhead, the RIAA preamp
section in the Convergent Audio Technology SL1 Legend, and the RCM Audio Sensor
Prelude IC. Of the three, I liked the last
one the best. It is small, inconspicuous, ridiculously cheap (I know,
manufacturers do not like to have their products or even their brand associated
with the word "cheap" – but here it really hits the nail on the head) and
comes from a tiny, two-people manufacturer RCM Audio in the city of Katowice,
Poland. Both Manley and CAT were fantastic in their own way and without thinking
twice I could share my life with them, who knows, maybe even "till
death do us part." But if I were to pick one product that would make life
fun and interesting – definitely not boring! – and surprising, it would be
the RCM Audio preamp.
Over the past – I think about five – years I
have been often met with confused stares, questions and even objections
hurled at this small aluminum box. Why that one? Why so cheap? Why so ugly?
Why from such an unknown company while I could have whatever comes to mind
(which actually is true). I have had one short answer to all these questions:
because it’s a device that proved great with all turntables and every single
cartridge I have ever tested. Both with the 100,000 EUR Transrotor Argos and the
astronomically expensive Air Tight PC-1 Supreme cartridge; equally well with the
most expensive cartridges from Dynavector and Miyajima Labs and with the top
turntables from SME or AVID. On the other hand, I have had the cheapest
preamplifiers from Pro-Ject, basic cartridges from Audio Technology, Denon and
Ortofon, and the Polish phono preamp was able to do justice to all, without any
gimmicks, and to bring out the very best in them. This
is the only phono stage with what I had to do that was so "stable"
the. It’s the only phono stage I have ever reviewed that is so "stable" and so
consistent, no matter what I’d hooked it up with.
And, from all I know, I’m not alone in that.
John Bamford who reviewed the preamp for the November 2009 issue of "Hi-Fi
News" was delighted with it and bought it as his reference device. And, from all
I know, there are more of us, journalists and owners of very expensive
turntable-based systems, who think similarly. It’s just that hardly anyone
admits it. Why? Here’s my answer: because the Sensor Prelude IC is cheap and
ugly, and because it comes from a country that only few people can locate on the
map (not to mention the city...). It is also because you cannot comfortably
select cartridge load. Now all this is about to change – ladies and gentlemen,
please meet the THERIAA.
The THERIAA is a completely new design from RCM
Audio and Roger Adamek, the company’s owner. In Poland, Roger (I will not
pretend we don’t know each other) has been primarily
known for his passion for analog. His distribution company RCM SC, out
of which grew the RCM Audio, had been for many years one of the few
places where you could listen to and buy turntables, cartridges, etc., despite
the fact that almost everyone wrote analog off. Roger and his team are probably
the best experts in Poland when it comes to analog. In his home audio system,
the RCM Audio owner has had for years the 30A and, since some time, the 30/12
turntable from SME that he is a distributor for in Poland, with a top Dynavector
cartridge. For years, he hooked up his turntables with the Sensor phono stage,
just like me, unable to find a good reason to replace it with something more
sophisticated. But something had to tip the scales and the new design, which had
been in the making for a few years, was brought forward and realized in the form
of the THERIAA.
From what I know, the preamp was designed by a
different team than that responsible for the Sensor, however, both the turntable
(SME 30 and 30/12) and the cartridge (top Dynavector), being Roger’s
reference, and Roger himself as the ultimate "reference point", remained
unchanged. The new device’s looks as well as its price are a completely different story than the first RCM Audio
It is a solid state dual-mono design, with a
separate power supply. The power supply is symmetrical and the coupling with the
main unit is via power cable terminated with very nice Amphenol plugs. The power
supply has three filtration stages, with no less than 125,600 µF per channel.
It employs capacitors from Elna, Panasonic (silver series), Nichicon Fine Gold
and Wima, all carefully selected through listening tests.
equalization circuit is fully passive. All passive components are
hand-selected, individually for each single unit. The preamplifier has the total
gain of 76 dB and boasts RIAA precision of +/- 0.1 dB (20 Hz to 20 kHz). Input
mode is selectable: balanced or un-balanced. Nominal output level is 2 V (9 V
maximum). Input capacitance is 100 pF. Gain can be adjusted in 8 steps (from 0.2
to 5 mV) and input impedance in 7 steps (from 20 Ohms to 47 kOhms).
When it comes to price – €9800 (incl. VAT)
– its design and finish, we are in the world’s first league. The enclosure
is made of 10 mm and 5 mm black
anodized aluminum plates. The feet are made of stainless steel mounted to the
device in a flexible manner.
The preamp is equipped with the following
· Error (I
assume red; never came up), indicating DC current on input
· Overload (I
assume red; never came up), indicating input overload
(orange), on during system testing
(green), indicating power-on; separate for the left and the right channel.
Looking at the THERIAA and
into its interior, let’s quickly go through some of the objections that
(I think) the audience had when they saw the Sensor. The price and appearance of
the new preamp is, as I said, the absolute top. OK, it still seems to be a
bargain because it doesn’t even come close price-wise to products from
Boulder, Kondo or even Zanden. But, I must admit, it is fairly expensive… The
manufacturer is still tiny and unknown although a lot more people now know it
and know where to find Poland. What remained unchanged is the not quite user
friendly cartridge load selection, at least compared to the Manley (knobs on the
front panel) or e.g. the Array Obsidian PH-2 phono preamp where all cartridge
load settings selectable with the remote control. Array is a manufacturer owned
by two Dutchmen, Chris van Liempde and Willem van der Brug that once
manufactured electronics for Van den Hul.
The main unit is housed in a very solid enclosure made of 5 mm
and 10 mm aluminum plates. The housing is manufactured in Germany by Fischer
Manufacturing to RCM specifications. The finish is professional. Maybe slightly
old-fashioned, alluded to e.g. by the
mounting of LED on the power supply, but nevertheless really classy. The
power supply chassis is more modest, but it is still OK. The top cover of the
main unit is lined with vibration damping
material. Strips of the same material are also on all other panels.
The front panel features eight LEDs in two rows of four,
indicating device’s current status. Two rows since it is a true dual-mono
design and can be viewed as two separate devices in one box.
channel separation is also visible on the rear panel – the inputs, gold-plated
RCAs, and the RCA and XLR outputs are far apart. That shows how far from each
other are each channel PCBs. At one side is a very solid Amphenol bayonet
power connector with gold-plated pins to connect a 2
m long DC power cord from the separate power supply box housing transformers
and rectifiers. There is also a grounding terminal (with which all manufacturers
seem to have problems – it’s either too small or too big, or something else
is not quite right – I honestly don’t know a single well-designed grounding
terminal…). And there are DIP switches to select input impedance, gain,
and balanced or unbalanced input mode. In my case the former always proved
The interior will please the eye of anyone who knows the stuff. It is divided into three chambers – one each for the left and right channels, and a small housing for the power cord. The channels are separated by a 10 mm aluminum plate and one channel is separated from the power cord by an aluminum angle bar.
Each channel is built on two PCBs – one contains voltage regulators and the other is gain stage with RIAA correction. The gain stage is based on ICs, five per channel. At the input we see THAT Corporation 1510, an ultra-low noise wide bandwidth amplifier with high gain. Interestingly, one of its intended applications in addition to audio systems is sonar... Next is a National Semiconductor chip I couldn’t read as it’s covered by a resistor. It’s a part of a protection circuit against DC in the input. The PCB also houses a large TL074 STMicroelectronics chip with JFET input, working as system logic (LEDs, relays, etc.) – it is not in the signal path.
The second gain stage is based on Burr Brown OPA2134 and THAT
1610. The circuit as a whole seems to be balanced despite the fact that there
are no XLR inputs. Passive components are excellent – they are precise
metallized resistors and Wima and EVOX (lots of EVOXs) polypropylene capacitors
as well as Nichicon Fine Gold and Panasonic electrolytic capacitors. DIP
switches are from Omron. The entire
unit is assembled very neatly, there is nothing to hide.
The second PCB in each channel, located closer to the front
panel, is a complex power supply. It contains 18 (per channel) electrolytic
capacitors for voltage filtering and three additional polypropylene capacitors.
Among them we see two (per channel) Linear Technology LT3080 voltage
regulators on heat sinks. Clean, professional design. But what else to
expect – Adam Kubec is a high-class specialist, owner of a company designing
automation systems for large plants such as coal mines. There can be no mistake,
makeshift or bungle. That is coupled with the audiophile experience of Roger
Adamek for whom the point of reference are products from SME, Dynavectora, CEC,
and Vitus that he’s been distributor for years.
the power supply. It is about half the size of the main unit and has a slightly
different chassis. Front and back are made of aluminum plates, while top, bottom
and the sides form a closed profile into which slides the power supply PCB.
Despite being simpler it is still a very solid, rigid design. Only the feet are
rather mundane – rubber hemispheres glued
to the bottom of the chassis.
The front panel sports a LED indicating power-on, the rear
features an IEC mains socket with a fuse and a large, mechanical power switch.
PSU is built on one big PCB. In the input, looking from the front panel (lined
with a dampening mat) we have a large mains filter and two transformers, one for
each channel. Behind them we see bridge rectifiers on heat sinks and quite a lot
filtering capacitors – six per channel. Both channels of the power supply are
separated from each other with a thick aluminum plate that works as shielding.
The rear sports DC power cord with four pairs of twisted copper wires and an
additional ground wire.
It is a very fine piece of manufacturing, showing extremely high theoretical and material design, the result of years of experience in distribution and manufacturing, of being an audiophile and music lover, a perfectionist.
With the THERIAA I did all that but it was subordinate,
derivative - something that would only assure me of the primary
trait of that listening test. That trait was contemplation. No, I don’t
use a rhetorical figure to state the
quality of the product, to "imprint" it in the reader’s mind. It is
obviously one of the tools of the journalist, of doing his job which after all
is to share some TRUTH about the product. This time, it was a total
Let me start with a small confession: I am absolutely,
completely satisfied with the RCM Sensor. I know it well and it’s been a great
reference point for everything I have listened to in my life. It is like a solid
"border post". Nevertheless, from time to time I’d come across a device that
was better in some aspects and once or twice (Manley, CAT, Vitus – OK then,
three times...) I heard or reviewed products that objectively speaking were
better than the Sensor. Period.
However, this time I was listening to a product that was not
just better. That much was "evidently evident", so to speak. Right from the
first album, listened to late at night on headphones, just after the RCM arrived
at my house – the 1987 "Making Music" by ZakirHussain [ECM 1349] – I was
aware I was listening to something from another story altogether. Describing
treble, bass or such like would be pointless since at this price level such
details simply do not apply. Here we listen to something else and something else
we hear. I will therefore use a few key words that will make it for a somewhat
short review but perhaps the densest, most
rich in meaning I have ever written.
is the first characteristic we notice. It seemed to me that the Manley Steelhead
sounds pure and that the Sensor has ultra-pure sound. That’s not true. Almost
all phono preamps I know, perhaps except the Vitus and the CAT, have more "cluttered"
sound. What I mean by that is not hum, interference or something equally banal.
The point is that when we have a dense recording, when we listen
to a poorly produced album, the best preamps such as the THERIAA arrange
and order all sonic aspects so that we can make sense of what’s going on and
easily reach behind the layer of record production flaws, intentional or
accidental deviations from neutrality. It was true with overly bright and
somewhat chaotically produced recordings, e.g. the
compilation "Stars and Topsoil" by Cocteau Twins (4AD, CAD 2K19) released on
white vinyl, but also with the recently released
anniversary version of the album "So" by Peter Gabriel (from
the "25th Anniversary Deluxe Edition Box Set", [Realworld,
PGBOX2]. Such recordings, and we can throw in here the failed
EMI reissues of Sinatra and Queen (digital remasters), sound dry and flat. Latest
vinyl releases from Munich-based
ECM sound even worse, as if ECM experience
All of these albums sound dry and ugly even on the Sensor. The
CAT, owing to its phenomenal saturation, toned down some sharp coloration in the
2-4 kHz range but in general still sounded weak. The THERIAA went deeper. It didn’t
muddle anything up, didn’t pretend that there was no
problem, but by ordering everything and clearing it of "debris" it reached
deeper into music and showed it as a one-time event, not a collection of
separate elements. And even though its treble is better and stronger than all
the above cited devices, it was never loud as it happened from time to time with
Another key word is coherence. It’s a characteristic I was able to experience a few times in my life, e.g. with the top turntables from AVID and SME, with the Transrotor Argos, and with the Air Tight PC-1 Supreme cartridge. Here I had the same thing. It is manifested in the interaction of all sound components and building something more, something beyond "sounds". We don’t feel the need to analyze what we hear but instead simply evaluate it, quite instinctively and naturally. In Hi-Fi analysis almost always precedes evaluation – we ask "what" and "why", "how" and "where". Sometimes also "compared to what". With the preamp from Katowice there is no such need. Everything is in place – there is very well developed treble and deep, meaty bass, there is saturated midrange and great color. Therefore, we accept it as something normal and given. We stop for deeper elements – why such an instrument, how are particular layers in relation to each other, what was the atmosphere at the time of recording. It is audible not only on purist reference recordings from Analogue Productions, Speakers Corner or ORG, but also on records cut from digital masters.
Of course – the closer to analog master tape and the higher
the rotational speed (45 rpm), the closer and more natural presentation. Yet,
the THERIAA doesn’t disqualify inferior pressings and poorly produced album.
It shows the "what" and "how" but
immediately reaches deeper, drawing us into music. As I say, I never liked Peter
Gabriel’s "So" production-wise and I think that there’s "something" that
causes subconscious fatigue, irritation, regardless of pressing, release and
format (incidentally, the worst is hybrid SACD CD remaster...). The reviewed
preamp somehow broke through this layer. Although it shows more detail by being
more selective than any other phono stage I am aware of, its treble seems to be
calmer than the Vitus or Manley preamps. Only the CAT did something similar but
it was through rounding and warming of sound.
And finally the category that is most
difficult to undergo falsification which is – in
my opinion – the basis for any scientific study (and that is what audio
listening tests are, as examination by inspection). I am talking about beauty.
The definition of beauty depends on each one of us; its understanding changed
both historically and geographically, etc. However, I think we can find common
ground for all these views. It is easier in our case, since we live in the same
time and – ultimately – the same place. And we listen to similar music.
And music through the THERIAA is simply more beautiful than
with other preamps. Even though I really appreciate the devices from Manley,
Vitus, CAT, but also from Boulder, Ypsylon, Zanden, Kondo, etc., they all bring
with them a "hump" of added meanings, brand, promotion, advertising,
some sort of "halo" that makes them no longer just "relays" because they affect
the way we "perceive" music conveyed by them. The Polish preamp seems to me
absolutely unpretentious against that background – from its appearance to its
approach to the subject. It sounds equally beautiful as the best phono preamps I
know; it is outstanding at differentiating recordings but does it somewhat
casually, without pomposity.