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Preamplifier + power amplifier

Trilogy Audio
903 + 993

Price (in Poland):
• 903 – 33 990 PLN
• 993 – 33 990 PLN

PO Box 56402
London | SE3 7WQ


Provided for test by: MOJE AUDIO

ic Poulsen seems to be a man in no hurry - this conclusion can be drawn by observing the time line associated with his products. The 925 integrated amplifier tested by us in 2015 was the result of several years of preparation (51.990 PLN with PRC remote). After re-starting the company in 2008, it took him two years to prepare its first product, the 907 phonostage (2010, 13.690 PLN), five years passed before the 933 headphone amplifier (2012, 12.990 PLN) was released and another year for the first "big" product, the above mentioned 925 amp. It's already a second half of the 2017, and only now the 903 preamplifier and 933 power amplifier derived from the integrated arrived on the market. The prototypes were shown last year at the High End Show in Munich.

Back then Nic told us that he'd chosen an integrated amplifier, because this design has many advantages for the designer: the signal path is short and he can control the current loops – mind you, not the feedback loop as Nic does not use it. As he said, zero-feedback amplifiers offer better flow of music and one can use them for hours as there is no listening fatigue because the structure of harmonic does not change much under different operating conditions, conditioned by the requirements of the music played. It was also important for him that he could use one less gain stage. However, he did not hide the limitations, mainly regarding the maximum power, resulting from the device's dimensions.

The integrated amplifier, same as integrated digital sources, ie CD players and music files players, have many advantages - see above. At some point, however, the designers are faced with a choice between different features and, for example, to gain higher power, to reduce the impact that the power amplifier exerts on the preamplifier, they have to think about separate devices. The result is the 903 preamplifier (33 990 PLN) and the 933 stereo power amplifier (33 990 PLN) created as a development of ideas from 925.

The output power of the 903 suggests that it was more about better control of the gain stages, more advance power supply, etc., because at 8 Ω it is capable of delivering 2 x 125 W, while the 925 integrated amplifier offered 2 x 135 W. Additionally this is not a balanced designed as opposed to the integrated. As I say – we get something at the cost of something else.

Trilogy, ISOL-8 | CEO

WOJCIECH PACUŁA: Could you tell me what was the goal of creating a pre+amp combo?
NIC POULSEN: Trilogy has become known for highly musical and involving sound. The goal, as always, is not to sacrifice this whilst pushing for greater resolution.

Could you describe (shortly) technical highlights?
One aspect we have always had in place with our power amplifiers where ever possible, is to have a true “Choke input” power supply for the heavy-current solid state output stage. I know of only one other high-end company that does this. It is very expensive to do and requires a lot of physical space and good design to get it right. However, the results help us achieve our goal.

The 993 also has a superior valve gain stage than its predecessor. But for a product to be highly involving and musical, the whole product needs to be balanced (I am not talking electrically here) as a whole. No one single thing is responsible. All technologies, parts and their implementation need to be consonant.

What music medium did you use while working on this project – LP, CD, or music files? And why?
I have always known how a product will sound as I am designing the circuit. It's intuitive for me. The final listening tests normally end up as just confirmation for me and maybe some minor alterations to the circuit or equally important, the circuit layout are made.

We use both CD and vinyl. There is no doubt that vinyl is the best but in our listening tests I have always judged a product over many days or even weeks, never “A-B” tests. This way you can rule out personal biases or moods, temperature and weather (pressure and humidity) variations, mains electricity variations, so CD tends to be favoured here.


It seems safe to assume that the separate system derived from the hybrid 925 integrated amplifier. The 903 tube preamplifier looks almost identical to the integrated, and is only slightly lower. Among its characteristic features there is a large, easily readable (hurrah!) display and a large volume knob. There are only three push-buttons on the front which could suggest little functionality.

Actually, the preamplifier's functionality is quite impressive. As it reads in manual, the device features an advanced control system that allows user to adapt the device to his needs and requirements. One can name inputs, determine their sensitivity, integrate the whole system via TAS link, use the internal clock to turn on/off the system, etc. One of additional options is also an extremely advanced phonostage with a whole palette of settings: gain, load impedance and capacity (7990 PLN).

The device's make and finish is perfect. Its chassis consists of aluminum plates. It features six line inputs, optional, Class A, phonostage module (MM / MC) and three line outputs. User can check out the total operation time of tubes, set the turn-on and turn-off time for the following days of the week, set the volume level at power up and maximum volume, and set gain for the home theater system ("unity gain"). The amplifier is equipped with three outputs - two main ones to connect power amplifiers and the "Send" output. The latter is a tape-out and it remains active also when the preamplifier is turned off.

The gain stage uses the 6H6П tubes in a grounded grid configuration that allows them to operate in pure Class A with the highest linearity and the lowest distortion. The output impedance is low for excellent drive capability. The volume is available in 1 dB steps. The preamplifier is supplied with a small plastic remote control RC-B, but a very nice PRC Personal Remote Control (2190 PLN) is also available.

One more interesting feature – the preamplifier requires user to input using the knob and display an individual PIN code delivered with each unit. Without it one won't be able to use the device


The power amplifier reminded me somewhat Burmester designs, due to the CNC machined radiator, which is also the front wall of the device. This is the only similarity though. The 933 Model is a hybrid power amp using 6H6П tubes, same as the preamplifier, in the input (voltage section) and the transistors in the output (current section). Also here the tube and the first transistor stage operate in class A - a lamp in a grounded grid with zero negative feedback. The power supply of this stage is fully discrete.

As Nic said, one of the most interesting features of this design is the application of a choke input power supply for the output stage. The choke is almost as large as a toroidal mains transformer, so it can easily be mistaken for it. Nic explains his choice as a way to eliminate current spikes and much more linear current draw, which reduces noise.

Several small FET transistors are used in the output stage, because the owner of Trilogy believes that the first watt of output power is the most important one and he decided to use these transistors for that purpose. When more current is needed large bipolar transistors step in. The amplifier has zero global negative feedback. Same as for the preamplifier, also here high-end components such as Welwyn resistors, custom Mundorf capacitors and copper (gold-plated) speaker terminals were used.

Trilogy devices are designed and handcrafted in the UK. Prior to shipment to the distributors, they undergo a 48- hour check procedure. They are delivered with a detailed, very nicely done user manual with Nic Poulsen's handwritten signature. Every element of this project seems well thought-through and refined – a classy product!

TRILOGY in “High Fidelity”
  • AWARD: BEST SOUND 2015 | Trilogy 925 - integrated amplifier
  • TEST: Trilogy 925 - integrated amplifier

  • Recordings used for the test (a selec- tion)

    • Czesław Bartkowski, Drums Dream, Polskie Nagrania „Muza”/Warner Music Poland 95843571, „Polish Jazz | vol. 50”, Remaster 2017, CD (1976/2017)
    • Dean Martin, Dean Martin, Capitol D 162295, „The Capitol Collector’s Series”, CD (1989)
    • Duda, Kanaan, Rudź, 3C, Soliton SL 719-2, 2 x Master CD-R (2017)
    • Ferit Odman, Dameronia with Strings, Equinox Music & Entertainment/Master Music XRCD24-NT019, XRCD24 (2015/2016)
    • Schubert, Lieder, wyk. Dietrich Fischer-Dieskau, dyr. Gerald Moore, EMI 55962 2, „Signature Collection", 4 x SACD/CD (1955, 1957, 1958,1959/2012)
    • Schubert, Song Cycles, wyk. Nathalie Stutzmann, Inger Södergren, Erato/Warner Classics 4623701, 3 x CD (2014)
    • Suzanne Vega, Close-Up. Vol.1, Love Songs, Amanuensis Productions | Cooking Vinyl COCKCD521, CD (2014)
    • Takeshi Inomata, The Dialogue, Audio Lab. Record/Octavia Records OVXA-00008, SACD/CD (1977/2001)
    • The Beatles, Sgt. Pepper’s Lonely Hearts Club Band, Apple/Universal Music Group 5745530, „50th Anniversary Edition”, CD (1967/2017)

    Japanese issues available at

    I have read recently in some article that women are in commend of many European armies. It stated that they are better prepared for conflict resolution and that they do not take risks without actual need, thus giving more guarantee for peace (and peace of mind). This type of "soft power" was defined by Joseph Nye, an American political scientist and is part of a dichotomous description of two types of state's power: "hard power" and "soft power." The latter is characterized by ability to gain allies and influence through the attractiveness of own culture, politics and ideology.

    I have the impression that the Trilogy products are exactly like that - as they used to say - a fist in a glove (or maybe in silk). The sound of the reviewed system at first seems very warm, “friendly” and devoid of sharp edges. For a long time it also feels delicate. These are features stayed with me until the very end of my listening session, and they are exactly what so many people look for and can't find in most systems. But over time I redefined a portion of these initial observations, getting to a slightly different place than the "warm" and "sweet" one I thought it was.

    Trilogy is incredibly dynamic. This is something that is not does not catch the attention at first, unless one knows what to look for. I started listening with two albums where drums played a key role, ie latest remaster of the Drums Dream by Czeslaw Bartkowski (Polish Jazz vol. 50) and The Dialogue by Takeshi Inomaty. They both sounded great, because I got the “meat”, slam, mass, but also very quick attack of sticks and impressive decay. The latter was not over-extended, nor did it have a clearly marked finishing line, and probably these elements were decisive for my first impression. Time spent listening to these albums was enough to understand that this is simply very natural, very "physiological" sound, that better describes the sound of drums, the combination of dynamics and velvetness than a precise slam.

    As I said, I started listening from these two albums. Each such test relays on a comparison between my reference device and the one under review. During the first phase I listen to one or two tracks using one and then switch to another, listens to the same tracks and then I repeat the whole procedure. And I do that many times until I am sure I have captured the most important features. Then I listen to longer fragments, often whole albums, so that these observations marshaled. It's a proven way that really works.

    This Trilogy setup did not allow me to focus on such a systematic comparison. I had to make some trips to pick up CDs that I did not use in my comparison. Its sound is so interesting, so addictive and absorbing that when I caught some theme I had to explore it and then move to another one. For me, just after the show of dynamic capabilities of this set, which was more impressive than what many more expensive amps had delivered before, I felt an urge to listen to some vocals appeared. Because everything I'm talking about revolves around the middle part of the band. Not because there is no treble or bass, but because all this softness and power forces everything into its place and listener tends to focus on what is most important to us, as human beings - on human voice.

    Nic Poulsen's amplifier has mastered the ability to deliver a large volume sound, a warm midrange, and yet the tonal balance is shifted to way down. In Ayon Audio preamplifier and Soulution power amp set the tonal balance is surely set lower! It became clear to me when I listened to something that required a lot of focus, like the old recordings of the 1930s and 40s. The type of amplifier that deliver warm sound make such tracks sound similar to each other and too “polite". In turn, these brightened top have a problem with the upper midrange, because that's where the most energy of the sound is placed.

    The Trilogy is not as stunningly resolving as my system, which somehow confirms the price difference. The Siltech interconnect which I used to connect the preamplifier and the amplifier from UK cost more than these two combined plus the optional remote control. For their price, however, are delightfully resolving. That is not what their magic is about, though, but rather playing everything with a single stroke in - at last I can say it - a beautiful, stylish way. It is this type of performance, i.e. cultural, but it's a cultural presentation backed with a huge power.

    Placing this set in a wider perspective, I'd put it in a collection with Kondo OnGaku in the center. The Trilogy would be placed quite close to this center, but in terms of dynamics and power it would be closer to Naim Statement than to Kondo or Vitus Audio. This is an extremely interesting combination of striving for smoothness and the need for slam, speed.

    This creates a very involving and emotionally engaging sound. It is not possible to listen to this system indifferently, despite the fact that it performs very well used in the background, playing quietly when one does something else. It shares many sonic features with live sound when even a poor wedding band or a firefighter's orchestra playing without any amplification, catches the ear even when one is just walking in the street nearby. This system offers something like that, but it lures with something else. A live sound is very open and bright but never too bright. The Trilogy darkens and warms up this sound – yes, it does that a bit – attracting to its performance with this unbelievable fluidity and naturalness, while capturing attention with dynamics at its best. Although it shows differences, it does not make everything sound just nice, it does so unobtrusively, delivering all details as something less important than the presentation as a whole.


    Because it's simply a beautiful sound - a little sweet, a bit warm and dense, but above all, naturally soft. These are elements one should realize from the start. But they are actually deceiving listener because it is a system with powerful dynamics and rich, always active bass, which what very clear when I listened to eg the new album by Duda, Kanaan and Rudź Trio 3C. I did not mention the sound stage because it, in a way, "transparent". It means it is always accurate and in the service of tonal balance. It is large, spacious, also out-of-phase micro information are presented accurately. Yet, it never draws attention to itself which could distract listener from what is most important – the music itself.

    That's what this system is, extremely cultural and polite. The Japanese release of Vader's new album (with additional EP!) will remain unopened for some time. In turn, all jazz, classic, even large orchestral albums, everything that included vocals or guitars was during this test in continuous rotation. It's an amplifier that makes us believe in audio again - if we lost this faith - or confirm it for us.

    Both Trilogy devices look fantastic! First of all due to the excellent make and finish, but also thanks to a great looking design. Both chassis are made of aluminum, and the radiator on the front of the power amplifier is machined CNC of solid aluminum block. The chassis surface is sanded and anodized. Thanks to the contouring of the fronts by light cuts from the top and the bottom, the devices gain some “lightness”. Not that they look heavy - their dimensions are (H x W x D): 465 x 312 x 106 mm for the preamplifier and 465 x 346 x 106 mm for the power amp. Due to these minor detail, however, they are not just another anonymous products but have a distinctive look. Let me add that the covers in both cases were damped with bituminous mats, and both stand on four small, rubber feet.


    Front and back

    The preamplifier captivates with a great, large and clear display – this type of displays should be an audio industry standard, rather than an exception. It is red and is composed of small LED "dots". It delivers information on volume level, and after entering the menu also other information. Next to it there is a large, easy-to-use volume knob, which is also used when navigating the menu. Next to it there are three small buttons – for a device with such advanced functionality their number is surprisingly small. On the side, in the milled cut-out there is a red power LED.

    The rear looks very nice, due to the robust, high quality RCA jacks. Because this is not a balanced design there are no XLR sockets. User has one phono and fine line inputs at his disposal, one of which can be converted into an “unity gain” input. When the preamplifier is not equipped with optional phono module the first input works as linear one. However, because the signal runs there using additional short wires, I would treat this one only as auxiliary.

    There are also three pairs of outputs - two with adjustable signal level for connection with power amplifiers and one with fixed signal for recording. The latter is also active when the preamplifier is turned off, which makes it easy to use with an external headphone amplifier.

    Next to the IEC socket, there is a mechanical on/off switch and six LEDs underneath that indicate the status of the unit. There are also TAS Link (RJ-45) sockets, designed for connection between different devices of this manufacturer. They allow you to turn them on with one button, but also to find out for how long have the tubes been already used in the amplifier, etc. This information is shown on the preamplifier's display.


    The interior is divided into two parts with a metal shield between them. One hosts a power supply and the control circuits, and the other all audio circuits. The power supply features three toroidal transformers with multiple regulators. Each section has its own power supply - the tube's power supply has been placed on the PCB along with it. In the heart of the preamplifier works a single tube, Russian 6N6П double triode NOS. The volume control is executed in the integrated resistor ladder and the inputs are switched using relays. The signal path is very short, most of the PCB is actually occupied by control circuits and power supply.


    Front and back

    The front of the power amplifier is made of milled aluminum. On the side there is a microLED, same as in the preamplifier. On the back there is a power switch, but the standby switch is placed underneath - it's a tiny bulge next to the front foot.
    The inputs feature the same RCA jacks as the preamplifier - the power amplifier is also not a balanced device. On sides manufacturer placed solid speaker connectors from Mundorf. Their metal parts are made not of brass but gold-plated copper. There is also an IEC power socket and a mechanical breaker as well as two RJ-45 communication sockets for the TAS system.


    The layout of the sections inside the amplifier is quite untypical. The whole amplifier section is placed on a single PCB bolted to the heat-sink. The rest (which is most) of the space is occupied by an extensive power supply. Its= is built around a very large toroidal transformer and equally large choke. They cooperate with a bank of small capacitors in the input and two large capacitors (per channel) on the PCB with output stages. These are excellent Mundorf M-Lytic capacitors. A separate power supply is provided for the tube – it includes fast Schottky diodes.

    The signal from the inputs is sent with long interconnects to the front, to a single 6N6П tube, the same as used in the preamplifier. At low power signal is amplified in small FET transistor operating in class A, and with higher current demand, four pairs per channel of Toshiba's bipolar transistors switch on. These in turn work in the AB class in push-pull mode.

    Remote control

    The RC-B remote control is small, plastic, not very nice unit. But it works and it's almost identical, but with other buttons, than the one Chord supplies it Blu Mk 2 transport with. With the remote control you change the volume and enter the menu. The optional PRC Personal Remote Control on the other hand is very nice and functional. Although it costs 2190 PLN I would suggest buying it right away.

    Specifications (according to manufacturer)

    Input impedance: 50 kΩ
    Output impedance: < 200 Ω
    Frequency range: 2 Hz-50 kHz +(/- 0.5 dB)
    Gain (input to main outputs): 14 dB (+/- 0.5 dB)
    Film Gain (input to main outputs): 0 dB (+/- 1 dB)
    THD: 0,05% (A-weighted, at 1 V)
    Phase: Phase correct (non inverting)
    Power consumption (max): 40 W
    Dimensions (HxWxD): 465 x 312 x 106 mm
    Weight: 10 kg

    Rated power (8 Ω): 2 x 125 W
    Rated power (4 Ω): 2 x 200 W
    Input impedance: 400 kΩ
    Distortion: Less than 1% A weighted at rated output
    Frequency range: 10 Hz-50 kHz (+/- 0.5 dB)
    Input sensitivity: 2 V RMS (@ full power)
    Standby power consumption: < 1 W
    Idle power consumption: < 50 W
    Power consumption (max): 700 W
    Dimensions (HxWxD): 465 x 346 x 106 mm
    Weight: 19 kg



    - Turntable: AVID HIFI Acutus SP [Custom Version]
    - Cartridges: Miyajima Laboratory KANSUI, review HERE | Miyajima Laboratory SHILABE, review HERE | Miyajima Laboratory ZERO (mono) | Denon DL-103SA, review HERE
    - Phono stage: RCM Audio Sensor Prelude IC, review HERE

    - Compact Disc Player: Ancient Audio AIR V-edition, review HERE

    - Line Preamplifier: Polaris III [Custom Version] + AC Regenerator, regular version review (in Polish) HERE
    - Power amplifier: Soulution 710
    - Integrated Amplifier: Leben CS300XS Custom Version, review HERE

    - Stand mount Loudspeakers: Harbeth M40.1 Domestic, review HERE
    - Stands for Harbeths: Acoustic Revive Custom Series Loudspeaker Stands
    - Real-Sound Processor: SPEC RSP-101/GL
    - Integrated Amplifier/Headphone amplifier: Leben CS300XS Custom Version, review HERE
    - Headphones: HIFIMAN HE-6, review HERE | HIFIMAN HE-500, review HERE | HIFIMAN HE-300, review HERE | Sennheiser HD800 | AKG K701, review (in Polish) HERE | Ultrasone PROLine 2500, Beyerdynamic DT-990 Pro, version 600 - reviews (in Polish): HERE, HERE, HERE
    - Headphone Stands: Klutz Design CanCans (x 3), review (in Polish) HERE
    - Headphone Cables: Entreq Konstantin 2010/Sennheiser HD800/HIFIMAN HE-500, review HERE

    - Portable Player: HIFIMAN HM-801
    - USB Cables: Acoustic Revive USB-1.0SP (1 m) | Acoustic Revive USB-5.0PL (5 m), review HERE
    - LAN Cables: Acoustic Revive LAN-1.0 PA (kable ) | RLI-1 (filtry), review HERE
    - Router: Liksys WAG320N
    - NAS: Synology DS410j/8 TB
    System I
    - Interconnects: Acrolink Mexcel 7N-DA6300, review HERE | preamplifier-power amplifier: Acrolink 8N-A2080III Evo, review HERE
    - Loudspeaker Cables: Tara Labs Omega Onyx, review (in Polish) HERE
    System II
    - Interconnects: Acoustic Revive RCA-1.0PA | XLR-1.0PA II
    - Loudspeaker Cables: Acoustic Revive SPC-PA

    System I
    - Power Cables: Acrolink Mexcel 7N-PC9300, all system, review HERE
    - Power Distributor: Acoustic Revive RTP-4eu Ultimate, review HERE
    - Power Line: power cable Oyaide Tunami Nigo (6m); wall sockets 3 x Furutech FT-SWS (R)
    System II
    - Power Cables: Harmonix X-DC350M2R Improved-Version, review (in Polish) HERE | Oyaide GPX-R (x 4 ), review HERE
    - Power Distributor: Oyaide MTS-4e, review HERE
    - Stolik: SolidBase IV Custom, read HERE/all system
    - Anti-vibration Platforms: Acoustic Revive RAF-48H, review HERE/digital sources | Pro Audio Bono [Custom Version]/headphone amplifier/integrated amplifier, review HERE | Acoustic Revive RST-38H/loudspeakers under review/stands for loudspeakers under review
    - Anti-vibration Feets: Franc Audio Accessories Ceramic Disc/ CD Player/Ayon Polaris II Power Supply /products under review, review HERE | Finite Elemente CeraPuc/ products under review, review HERE | Audio Replas OPT-30HG-SC/PL HR Quartz, review HERE
    - Anti-vibration accsories: Audio Replas CNS-7000SZ/power cable, review HERE
    - Quartz Isolators: Acoustic Revive RIQ-5010/CP-4

    - FM Radio: Tivoli Audio Model One