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atelier 13 audio

THÖRESS SE-845 Monoblock

"Reinhard Thöress set out to exalt the treasures contained in the Triode tube, through a classic approach that has proven itself and a deliciously Retro look, a sound result unlike any other in its density, its presence, its energy and its realistic spatial presentation, serving all the emotion contained in each recording. Those who are connoisseurs of Valve-halla will be delighted by the Thöress amplifiers and their rare musicality"

A Tribute to Professional Audio Components from the Golden Age of the Vacuum Tube! 

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texturally rich ... emotionally intense !




845 Single-Ended Triode Mono Power Amplifier

The SE845 Mono Amplifier is an all-tube power amplifier employing the famous 845 filamentary power triode in single-ended (Class-A) operation mode for an output power of up to 20 watts into a 4, 8 or 16 ohm loudspeaker load. It is the flagship of our all-tube power amplifier line.


The amplifier is entirely based on SINGLE-ENDED ZERO-FEEDBACK schematics. Decidedly ignoring the fact that many music lovers persistently believe in the myth that balanced technology (and the associated cable configuration with XLR connectors) is generally superior over single-ended concepts. Readers who want to learn more about our view on balanced techniques and our general design approach are encouraged to read the paper (THÖRESS - Behind the Curtain) available on request.


The 845 is a brightly glowing filamentary tube which requires around 300V peak-to-peak voltage swing at the control grid for full excitation while presenting a critically high internal impedance of about 2000 ohms to the output transformer (OPT). Designing a driver stage and an OPT which allow to fully exploit the enormous sonic capabilities of the 845 triode are therefore highly challenging tasks. In our SE845 monoblock the power tube is driven by an extraordinary single-stage arrangement employing two EL822 power pentodes operated in triode mode with high idle current. The driver is so powerful that it could (theoretically) drive a loudspeaker load with very low distortion on its own.


Furthermore, the proprietary output transformer (OPT) is made in-house and features a highly elaborated dual-coil winding over a large tape-wound cut core (C-core) to ensure very low transformer distortion and ultimate frequency response. (The OPT allows for precise matching of a 4, 8 or 16 ohm loudspeaker load to the power tube by way of jumpers soldered to the secondary terminals.) These design choices are to a large extent responsible for the richly textured, clear, warm and dynamic sonic presentation of the SE845 monoblock, particularly when combined wiuth high sensitivity loudspeakers, or with our 2CD12 or 1D66 loudspeaker.


The SE845 amplifier is built with meticulous hand construction using our proven point-to-point wiring techniques. 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.

The SE845 Mono Amplifier is an ultimate component and as such a worthy complement to our Dual Function Amplifier or Full Function Preamplifier. It easily outperforms competitive products regardless of price and certainly measures up to the expectations of even the most critical and experienced music lover.



Specific design choices guarantee low noise operation even when the SE845 monoblock is combined with a highly efficient loudspeaker such as our 2CD12 model or even a more efficient horn component.

  • Firstly, the 845 tube is DC heated whereas the cathode point of each individual tube can be balanced with respect to its filament by means of a control knob (rotary potentiometer) on the rear panel. Once the balance adjustment has been carried out the signal current is distributed uniformly over both ends of the 845 filament and residual hum due to ripple of the heater supply voltage vanishes (reaches a minimum).

  • Secondly, our mono block has been specifically designed to have a moderate gain (low input sensitivity). This ensures that the idle noise of the line device remains inaudible in all possible scenarios. Notably, this design choice also ensures conveniently fine volume adjustment.





The SE845 mono amplifier is equipped with a proprietary mains transformer produced in-house to ensure the highest possible quality and reliability. This part has been optimized for low body noise emission and low leakage. Nevertheless, it is mounted to the chassis via isolation elements in order to eliminate even the slightest interference of residual transformer vibrations with the circuit.


Since the mains transformer is produced in-house we can easily built transformers for all kinds of mains voltages on demand, for example 100Vac (Japan), 120Vac (USA, Canada), 220Vac (South Korea, China, Thailand, Indonesia), 240Vac (UK) or 245 Vac (Australia).

F E A T U R E  O V E R V I E W

  • All-Tube Mono Power Amplifier utilizing the famous filamentary 845 power triode in single-ended operation mode​

  • 2x20 watts of output power

  • Minimalist (pure class-A) zero-feedback schematic

  • Powerful single-stage driver utilizing two CV2382 (EL822) power pentodes operated in triode mode at high idle current


  • High grade electrolytic capacitors (made in Germany) in the power supply

  • On-the-fly selectable gain via 6-position rotary switch on the rear panel, 2 of which positions are assigned with subtle bass boost presets

  • C-core filter choke made in-house


  • Ultimate tape wound cut core (C-core) output transformer with dual-coil winding manufactured in-house

  • Precise 4, 8 and 16 ohm loudspeaker load matching via jumpers soldered setting to the secondary terminals of output transformer


  • Low noise low leakage mains transformer produced in-house for 230Vac (115Vac via jumper setting). 100Vac (Japan), 120Vac (USA, Canada), 220Vac (South Korea, China, Thailand, Indonesia), 240Vac (UK) or 245 Vac (Australia)

  • Full hand construction, point-to-point wiring throughout

  • Non-magnetic case (aluminum throughout

    • Anodized printing on front and rear panel

    • Powder-coated chassis and lids


  • Dimensions - mm : 

    • 150 W x 595 D x 330 H 

    • H / 330mm = 20mm (feet) + 210mm + 100mm (tubes over case)

    • D / 595mm = 575mm + 20mm (speaker binding posts)

    • Dimensions of the shipping crate - mm:

    • 950 D x 400 W x 460 H

    • Shipping weight : 18Kg each



Individually Made in Germany

MSRP   $ 13,000

MSRP   $ 16,50ELROG 845

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Show & User-System Coverage

Courtesy of Kwangho Kim’s Hi-Fi 

Please Listen with Quality Headphones at Youtube Hi Res Settings

What the say ...


Wojciech Pacuła |  Nov 1, 2017  

Think of the German system as a carrier of emotion. It's an amplifier that will not leave you indifferent to the music, that will engage you, pull you in, attract attention, but it will also calm you down. It delivers an extremely full, rich sound, as if the purpose is to prove that only SET amplifier can perform in this way.


The emphasis is on the lower midrange, but there is also a low bass and a nice top. It presents a great space, building it in the form of a "bubble", also around us. It energizes the air in the room with ease, including it in the created musical world. It offers enough power to drive even large speakers, but you should not exaggerate the size of the room it will play in.


It's a masterful and beautiful amplifier ! ... and the DFPre is an even better headphone amplifier !

Haute Fidélité

Bruno Castelluzzo  |  July, 2022  



Despite our fears given the 20 watts announced, the SE-845 Monoblocks performed very well on our PMC MB2 Se speakers ... with a sensitivity of 90 dB/W/m (8 ohms) ... and preceded by the DFPre preamplifier. This, even if loudspeakers with higher sensitivity would have been a preferred match ... such as the Thöress 2CD12 or Thöress 1D66.


Nonetheless, the incomparable qualities of these 845 triodes "stand out" through their ability to express an extreme fluidity of the sound message, a harmonic richness unlike any other, and a sense of incredible naturalness ... without any electronic artifacts ... Quite to contrary, they are imbued with a fullness of sound and a musical "breath" that only well-implemented directly heated triodes are ultimately capable of offering.


The declared power belies the dynamic ease that we experienced ... which is, after all, the prerogative of large triodes like the 845, where the bass goes down deep with all the textural heft. The intricate nuances are expressed with total freedom, without restraint, because no negative feedback is used to stabilize the circuit. Such feedback often limits the natural dynamics of a tube biased in pure class A.

The rhythmic pace, harmonic foundations, and the tonal substance are expressed masterfully on the Synchro System album [ Adé & His African Beats ], where the many percussive instruments such as maracas, congas or shekere convey a formidable realism, and a superbly refined textural grain.


What momentum ! ... and what communicative swing ! Nothing is filtered ..which gives free rein to the dynamics of the SE845. These captivate with their warm and richly textured sound presentation.


The quality of the mid-treble is divine, and retains all the characteristic sweetness of the tubes which have a beautiful harmonic gradient. Moreover, the extreme silky treble is never exaggerated, and integrates into the rest of the spectrum naturally.


The tonal balance here is perfectly homogeneous, coherent at any sound level. The volume level can be raised without giving the impression of being at the limit, thanks to the powerful driver stage that fully modulates the 845.


With the orchestra of Lalo Schifrin, accompanying Jimmy Smith's organ, on “The Cat” (Verve), we are rewarded with an explosion of dynamics, an unleashing of perfectly readable and differentiated sound colors. The modulation of the Hammond B-3 organ is magnificent in its realism and life, provoking a blissful smile on our faces ... a sure sign that musical pleasure is omnipresent !



The Thöress SE845 are not ordinary amplifiers. Their unique and seductive personality will pair well with speakers of good sensitivity, to reveal their magnificent nature.


The SE-845 Mono will meet the expectations of the most critical and difficult music lovers, by distilling a rare sonic beauty, the prerogative of triodes with very low distortion and a smoothly graduated harmonics.


These are true sonic marvels, full of delicacy ... with the antediluvian aesthetics of an industrial machine, but exude a refinement that is ultimately very desirable ... and they are not really "inaccessible".


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