⌈ REINHARD THÖRESS founded the company under his name around 2000, shortly after graduating from college. He majored in mathematics, and was a university teacher for a while. He received his degree from RWTH University in Aachen, a border town near where German, Belgian and Dutch territories meet; it is still where the company is headquartered today. It specializes in building high-performance loudspeakers and tube amplifiers that look like they came straight out of the 1950s. We test its latest amplifier, the SE300B monoblocks. ⌋

OT ONLY THE DEVICES of this German company, but also the full name - THÖRESS. Puristic. Audio. Apparatus - are far from standard ones. And that's because their construction and design are styled in the 1950s fashion. Reinhard Thöress, founder, owner and designer in one person, assumes that those were the golden years in audio, when it was not the accountant who counted in the company, but the engineer.

In a document titled Thöress. Behind The Curtain, posted on the manufacturer's website, we read:

In case of amplification, I strongly believe in the supremacy of MINIMALISTIC, SINGLE-ENDED, ZERO-FEEDBACK, VACUUM TUBE TOPOLOGIES while strictly avoiding balanced schematics, push-pull operation in particular. My Parametric Phono Equalizer (Phono Enhancer), for example, offers purely active MC amplification with excellent signal-to-noise performance by solely employing two single triodes (per channel) operated in single-ended mode with HIGH IDLE CURRENT.

So these are, roughly speaking, the basic principles guiding him. What’s curious, is the strong emphasis placed on minimizing noise and avoiding balanced circuits. The former is based on the selection of appropriate techniques, and the latter comes from experience - let's add: exactly the same as mine. Although engineers and people associated with the recording studio are ardent supporters of balanced circuits, listening experience tells us that it is impossible to make a device with a perfectly symmetrical layout. And only then are distortions canceled out.

Being a tube lover, however, Mr. Thöress doesn't shy away from modern solutions, reaching for non-magnetic materials for chassis and for transistors, which he uses in some amplifiers (→ EHT MONO). Also, the power supplies work with silicon diodes rather than tubes. The enclosures are made of aluminum, rather than steel or cast iron, as used to be the case, since aluminum has been proven to have less impact on the audio signal.

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| A few simple words…

REINHARD THÖRESS
owner, designer

⸜ Company Thöress makes all inductive components in-house

THE 300B MONO BLOCK was the first products I have designed and built in small series, an ancestral form of the actual SE-300B amplifier so to speak. The SE300B mono amp has reached its evolutionary dead-end a decade ago or so. Nowadays the THÖRESS product line consist of 10 amplifier and loudspeaker products (Puristic Audio Apparatus, as I call them) which have been primarily and initially developed to serve my own needs as a music lover.

When I got started with tube based audio electronics acquiring decent output transformers was a big and bank breaking deal. These crucial parts had to be imported from Japan where (much in contrary to the situation in Europe) single-ended triode amplifiers enjoyed vivid popularity among audiophiles. So I was condemned to dive deeply into audio transformer design and make my own inductive parts in order to realize my projects.

Over the years I have designed and manufactured almost any kind of inductive part one can think of...output, interstage, MC step-up transformers, anode and filter chokes and all kinds of mains transformers. So it is no wonder that the SE300B mono amplifier excels with a perfectly flat frequency response with 3dB down points at about about 5Hz and 100 kHz! Without any transformer resonance peaks above the pass band, I should add!

⸜ Thöress winder for transformers and chokes

At a rather early stage of my career it became evident to me that I had to fuse the ancient vacuum technology with the capabilities of contemporary solid state technology in order to reach ultimate sonics. Accordingly, I freely dispose of the whole palette of ingredients and spices the universe of electronics offers to me. As a matter of consequence, in my circuits vacuum tubes are often complemented by solid state devices like light emission diodes, MOSFETs or bipolar transistors as side elements in order to create optimal high current operation conditions for the tubes, aiming at the lowest possible distortion figures and in-harmonicity in complete absence of negative feedback correction.

The more or less subtle retro touch my products emanate are understood as a homage and tribute to the tradition of professional audio components from the early times of HiFi which I consider as a major root and inspiration of my own design philosophy. RT

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▌ SE300B

THE SE300B IS THÖRESS' latest product. It's a single-ended, triode (SET) power amplifier based on the 300B tube, a direct glow triode. In this circuit, it guarantees 10 watts of output power (which is quite a lot), although the manufacturer does not specify at what distortion. In general, we won't learn much about how this device measures.

The output tube is the most important element that distinguishes this amplifier from the 845 Mono (test → HERE). The appearance of the device, the layout of the components inside, the transformers, and finally the input layout, are very similar. The device was conceived as a "functional machine". It takes the form of a long, rather tall, though narrow cuboid facing forward with a narrow wall. The sides are painted in a distinctive dark green color referring to the color scheme of the mid-20th century.

I am talking about „function” for a reason. If you have a moment to close your eyes, please do, and imagine that the amplifier is facing the side towards us. What do you see? In my case, it's a slightly modified version of QUAD's iconic amplifier, the 'II' model, and to some extent the McIntosh MC275 (more → HERE). Now imagine the back of the SE300B up front. What has just appeared on the screens of our eyelids? - Well, I assume, a device similar to the Kondo OnGaku, only with the input on the front instead of the side (more → HERE ⸜ PL and → HERE).

This layout of inputs, outputs, transformers and amplification elements is intentional. When perfectionist audio was born, the biggest issue was significant hum, and one of its sources was the proximity of these sections. Before we get to that, let's say that it's not the only one. The issue in amplifiers with 300B in the output was that the heater voltage (5 V) was an AC voltage, and the filament and anode in it are powered from the same point. This problem is solved by rectifying the supply voltage, but you also need to determine it precisely - this is what the "Symmetry" knob is used for in the tested amplifier. It is not a perfect solution, which we will discuss at another time, but we get low hum thanks to it.

The second way to reduce interference from the power supply is to physically separate the input and output tubes, and the transformers from all of them. And that's why the German amplifier looks the way it does. The line inputs and input tubes are placed in it at the back, far from the power section. Nota bene - the tubes are the magnificent CV2382/EL822 (V2382KB/QDD) NOS-type power pentodes, somewhat similar to the EL84, operating here in a triode arrangement. This section was designed for earlier equipment from this company including the - mentioned - 845 Mono model.

From the CV2382 tubes, the signal runs forward to the slightly distant end tube. It's underneath it, slightly in front, that the large output transformer, with classic EI plates, was located. It's far enough away from both the 300B and the input that it doesn't interfere with them, and close enough to the output tube that the connections between them are short. The signal to the speakers has a high level, so it is less susceptible to interference. The output terminals are single, but you can adjust the output impedance for your own speakers - just solder (or order soldered) outputs on the transformer.

The power supply transformer and choke is a beautiful-looking "double C". The manufacturer says that it is a ribbon transformer, not a wire transformer, with an air gap in the core ("cut-core"). All of these, including the choke, are made in-house by Thöress. The power supply was placed sideways to the gain circuit, which also reduces interference. And the tubes on top are quite high - this is why the amplifier itself has a high chassis. The circuit uses very good components, such as Vishay capacitors and resistors, oil filter capacitors for the anode voltage, etc. The circuit is assembled by hand using the point-to-point technique.

It's a circuit that looks simple, but has been thoroughly thought out and optimized for the best possible power energy transfer with the lowest possible distortion. The manufacturer says about it:

The amplifier is built with meticulous hand construction using our proven point-to-point wiring techniques whereas much care has been taken in arranging each aspect of the internal construction to ensure low noise performance, ease of service and the highest reliability for many years to come.

To paraphrase a classic I will say: simple, yet beautiful.

▌ SOUND

˻ HOW WE LISTENED ˺ Thöress SE300B monoblocks were compared to my reference, Soulution 710 transistor power amplifier, and drove Harbeth M40.1 speakers. The initial amplification was handled by the Ayon Audio Spheris III tube preamplifier, but it's worth mentioning that the manufacturer offers its own very interesting FF Pre.

The signal between the preamplifier and power amplifiers in both cases was carried by an Acrolink 8N-A2080III EVO interconnect. The amplifiers were powered by Acoustic Revive Absolute Power cables, and the signal to the speakers was carried by Crystal Cable Da Vinci speaker cable (more → HERE). The signal source was an Ayon Audio CD-35 HF Edition SACD player.

Thöress amplifiers are large enough so that they do not fit on the top shelf of the Finite Elemente rack I use. So I placed them on the floor, but on Acoustic Revive RST-38H platforms and RKI-5005 pads from the same company.

» RECORDINGS USED FOR THE TEST ⸜ a selection

⸜ A Day at Jazz Spot 'Basie'. Selected by Shoji "Swifty" Sugawara, Stereo Sound Reference Record SSRR6-7, 2 x SACD/CD (2011).
⸜ TADEUSZ NALEPA, To mój blues, Polskie Nagrania „Muza” | Universal Music Poland/Tidal Master, FLAC MQA 24/44,1 (2020).
⸜ POLYPHIA, Remember That You Will Die, Rise Records/Tidal Master, FLAC MQA Studio 16/44,1 (2022).
⸜ TWO FEET, Pink, Republic Records/Tidal Master, FLAC MQA 24/44,1 (2020).
⸜ SPACE, The Best of…, Virgin | La Si Belle Musique/Tidal, FLAC 16/44,1 (1998).
⸜ AURORA, All My Demons Greeting Me As A Fiend, Decca/Tidal, FLAC 16/44,1 (2016).

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THERE IS SOMETHING ABOUT THE SO-CALLED "MAGIC of the first sentence." When Joanna Nowakowska of Media Rodzina Publishing says that when searching for new authors on Wattpad she pays attention to the first sentence of a story, she immediately adds that it determines the energy in the entire work (Magdalena Piekarska, Tam, gdzie żyją opowieści, "Press", 07-08/2023, p. 47). It had a similar significance for many authors, such as John Irving, author of The World According to Garp, for whom it is a key, almost sacred thing. So they all grind long on this opening sentence, because they believe it is in a way a novel in a nutshell.

Every now and then, maybe even more often, it also happens when I listen to an audio component - the first album, the first track, and even the first seconds "set" the perception of the whole thing. So when I heard how the Thöress monoblocks played JOHN COLTRANE's Crescent I already knew what to expect. And they played it beautifully, oh - how beautifully! Soft, resolving, warm, dense, in an open way - all at once.

There was not a hint of mechanics in this presentation, as if the amplifiers were transforming the signal to convey every detail as accurately as possible, but as it was played, not recorded. It's a sort of "leap" over the entire recording and playback process directly to the moment when the music and sound were born. That's why the leader's saxophone was so compellingly "present," and ERIC DOLPHY's baritone saxophone, played immediately afterwards in God Bless The Child, had an incredibly natural descent and was big, present, tangible.

I played both tracks from an SACD prepared by Shoji "Swifty" Sugawara, a hugely important figure for Japanese jazz, whose club Count Basie once played in, and where you can listen to music every day through a top-of-the-line, vintage JBL system. He has impeccable taste, as demonstrated by this very two-disc album. Nowhere else would tracks as disparate as the previous two and the LOUIS ARMSTRONG's live recording On The Sunny Side Of The Street, recorded in 1947 and "copied" from slightly crackling acetal, would sound so coherent.

For the special feature of the tested Thöress amplifier is, right after the aforementioned ability to get to the heart of the music being played, very rarely seen energy transfer. When a sound wave reaches the microphone diaphragm, most of its energy is converted into current, but some is irretrievably lost. The same happens at every stage of recording and later playback. The extinct elements of the original sound are usually low-level signals, responsible for whether or not the presentation is believable, for phase shifts, soundstage, etc.

And that's where the amps we're testing this time truly shine. Because it seems as if all those details that came to them are reproduced without any modifications. That's why the sound is so remarkably natural and tangible. The device differentiates recordings, that's clear, after all, HARRY JAMES' explosive Caribiribin - Trumpet Blues and COUNT BASIE's Jumpin' At The Woodside played immediately afterwards sounded completely different. The former open at the top of the band, accurate, with precise attack and very well captured dynamics, while the latter at one dynamic level and with limited frequency response.

What they had in common was the saturation of the midrange, the fantastic shaping of the sound attack and the ability to sustain it in such a way that everything came together, was "sticky" in a way. At the same time, this viscosity describes the timbre, not the dynamics, because the latter was above average, but without falling into hyper-literality. Thus, if one were to describe the timbre of this device in isolation from other features one would have to say that it is warm. Those of you looking for aggressiveness in the sound will not be thrilled.

But those looking for energy in this presentation will find more than enough of it. Even in the rather compressed, slightly rumbling Pozwól mi być z tobą tu by TADEUSZ NALEPA. Positioned by the producer in the right channel, the two electric guitars are not far apart - the rhythm guitar a little further to the right, and the solo leader a little closer to the center. But they're close enough to each other that it's easy to fuse them into one sound. And Thöress distinguished them not only timbrally, but also rhythmically. There was no doubt that they have a different place on stage, emphasized, moreover, by the longer reverb on Nalepa's guitar.

I loved it how it came out in the intro to the Ego Death track by PYLYPHIA, featuring Steve Vai on guitar. Just as before in Nalepa's song, the sound was big, had a strong punch and very, really good bass. The thing with 300B tubes is debatable, because to generate low, well-controlled bass, after all, you need a lot of current, and not many designers know how to ensure such capability. Here there were no major problems with it, except perhaps at the lowest end of the band.

The low tones are generated strongly, unambiguously by the SE300B, with great dynamics and no audible distortion. Even with speakers as difficult to control as the Harbeth 40.1. As I've written several times before, many, even powerful amplifiers don't handle them very well. But all it takes is an amplifier with a stable power supply and high peak current capabilities for them to "sing". And it doesn't matter whether it's a 100-watt transistor or a 10-watt tube, as in this case. The only difference is in the maximum sound pressure level (SPL) they manage to generate. In my case, at a distance of two meters from the speakers, it didn't matter much.

Even with such difficult material as the BBY track by TWO FEET. Difficult, because with a very low, electronically generated bass, playing with the phase on the guitar and vocals, with a motoric tempo, etc. None of these elements can be weaker, because if just one does momentarily everything "falls apart". The amplifier from Aachen showed all this effortlessly. It played a very big sound with strong and low bass. This latter is not super-selective, it's not that type, but it keeps everything in check by controlling the rhythm.

And perhaps all that does not matter? Because it may happen that it is listened to by someone who doesn't know it, doesn't want to know it and doesn’t give a s...t. Good!, for someone like that, the most important thing will be that Thöress will play almost any music as if it were at that moment the most important thing in its life. Whether it's effing jazz classics, or music born in the guts of a computer, or even older pieces that usually sound light and "thin," like Magic Fly by SPACE. You know this track, even if you don't associate it at the moment - but you haven't heard it yet in a way that Thöress presents it.

▌ Summary

THE SOUND of the tested amplifier is super-pure. I didn't mention it in the test, because it's a basic thing, it's what everything comes from, but which, it seems to me, is often misinterpreted. Purity in this case is the absence of coloration, but not only that no coloration is added, but also that nothing is „deducted”. Purity only with the former kills the music, and that is bad purity.

Thöress plays everything with graceful, effortless ease. And although in dense recordings like AURORA's Home from her excellent album All My Demons Greeting Me As A Fiend, when I cranked up as much as I could, the sound was slightly overdriven, I was way out of my comfort zone at the time. At normal volume in conditions such as those in the High Fidelity listening room, you can play music loudly and it will be full scale, clean, immersive and extremely dynamic. It is truly a beautiful sound.

▌ DESIGN

The SE300B from Thöress are tube monaural amplifiers with solid-state power supply section. They use a directly glowing 300B single-ended triode and two CV2382/EL822 triode pentodes; they work as input buffer and 300B driver. The amplifier operates without global feedback.

The SE300B shares a chassis and design with another amplifier from the company, the 845 Mono model. Their distinctive feature is that they are very long and narrow. This is an example of the application of the "form follows function" strategy, mainly in turn-of-the-century architecture, in which the appearance a product takes on is dictated by the function it serves. Here, the idea was to keep the output transformer and the tubes and input circuitry as separate as possible. That's why the inputs are at the back, right next to the small tubes, and the output circuit at the front far from them.

On the front panel, there are only holes arranged in the letter "T" and an orange light indicating power on status. On the back, in turn, there is a pair of gold-plated speaker sockets, an RCA input and a knob which is part of the output tube's heater circuit; with its help we can reduce hum. As with previously tested amplifiers from this company, it was audible in my system only when I put my ear to the woofer, and only minimally.

The tubes are located on the top panel. In the input and control section, there are two CV2382/EL822 (V2382KB/QDD) NOS-type power pentodes, somewhat similar to the EL84. Invented in the 1960s, these were used to amplify video signals. They work in parallel and were connected via a capacitor to the output tube, 300B triode from JJ Electronics, operating in A Class. So the Thöress amplifier does not use Chinese or, more importantly, Russian tubes. This is important.

The electrical circuit is spatially assembled, using mounting rails. The powerful output transformer of the - surprise, surprise - "double C" type. The manufacturer writes that it is a ribbon transformer, not a wire transformer, with an air gap in the core ("cut-core"). The chokes in the power supply are made similarly, by the way. Both of these components are made in-house by the company.

The large power transformer is a classic design, based on EI shapes, and has two secondary windings, working with Shottky diodes and a choke for the triode. The anode voltage of the input tubes is stabilized. The voltage for the latter is filtered in six large capacitors from German company ELECTRONICON. They are oil capacitors. The heater voltage for the output tube is rectified, and the aforementioned "Symmetrie" knob on the rear panel is used to establish the lowest possible hum in the speakers. The input and output tubes are connected by an NOS-type capacitor from Rifa. ●

▌ Technical specifications (according to the manufacturer)

Nominal output: 10 W
Power consumption: 75 W
Dimensions (W x H x D): 150 x 330 x 595 mm
Weight: 14 kg/pc.