THÖRESS SE-300B Monoblock

HIGH FILDELITY

Wojciech Pacuła |  Sep 1, 2023  

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The SE300B is THÖRESS' latest product. It's a single-ended, triode (SET) power amplifier based on the 300B tube, a direct heated 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. 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.

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INTENTIONAL LAYOUT

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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. 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.

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.

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THE SOUND

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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.

The special feature of the Thöress amplifier is -- right after the aforementioned ability to get to the heart of the music being played -- a very rarely experienced 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 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. 

The HARRY JAMES' explosive Caribiribin - Trumpet Blues ... and COUNT BASIE's Jumpin' At The Woodside, that we played immediately afterward, 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 it has a very low, electronically generated bass, playing with the phase on the guitar and vocals, with a motoric tempo, etc.

None of the aforementioned elements can be weaker than the other, because if just one does momentarily get weaker, everything "falls apart". The amplifier from Aachen showed all this effortlessly. It played a very big sound with strong and low bass. The latter is not super-selective, it's not that type, but it keeps everything in check by controlling the rhythm.

And perhaps all this 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 ! ...

... because -- 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 realize it at the moment - but you haven't heard it yet in a way that Thöress presents it !!

SUMMARY

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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.

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