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Thöress F2A Integrated Amplifier



The amplifier can be employed as a stereophonic power amplifier (in combination with a line or full function preamplifier), in which case the volume controls of the amplifier serve as input attenuators to match the gain of the line device to the efficiency of the loudspeaker.
Our All-Tube Integrated entirely relies on minimalist single-ended zero-feedback schematics. Deliberately 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 to single-ended concepts. Readers who want to learn more about our view on balanced techniques and our general design approach and are encouraged to read the article (THÖRESS - Behind the Curtain) available on request.
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. Although reasonably priced, the F2a11 Integrated shares the non-compromise approach with our larger mono amplifier models. It is by no means an entry-level component, but a state-of-the art device which is likely to be sonically superior to any competitive product regardless of price. The sound of our F2a11 amplifier is powerful, warm, clear and natural. Particularly when combined with our highly efficient 2CD12 highly efficient loudspeaker the sonic presentation is of utmost refinement and will easily meet the expectations of even the most critical and experienced music lover.


The amplifier comprises 3 line level inputs (2x3 RCA jacks) with equal gain status selectable via rotary dial located on the rear panel. High-grade continuously variable single-potentiometers are employed for separate (manual) volume control of the channels. These parts are made to our specifictions by ALPS in Japan to allow for conveniently fine volume adjustment (taper with low angle sensitivity). Each pair of
potentiometer is hand-picked from a larger production batch by careful measurement to ensure equal attenuation characteristics with respect to rotational angle (hence the slots surrounding the volume knobs are reliable scales for balance adjustment). Notably, it is not possible to install remote volume control on the F2a11 Integrated. Music lovers who consider remote volume control as an indispensable feature are encouraged to take a closer look at our EHT Integrated Amplifier!


The F2s11 Integrated Amplifier is equipped with proprietary output transformers (OPT) of ultimate quality made in-house. These parts allow 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. Furthermore, the mains transformer is also produced in-house to the highest possible standards. Thus we can easily built transformers for all kinds of mains voltages, for example 120Vac (USA, Canada). Although the mains transformer has been optimized for low leakage and ultra low body noise emission it is mounted to the amplifier chassis via isolation elements in order to eliminate even the slightest interference of residual transformer vibrations with the circuit.

F E A T U R E  O V E R V I E W

- All-Tube Integrated Amplifier with 2x6 watts of output power utilizing the famous
Siemens F2a11 Power Pentode in single-ended triode mode and a highly linear
12SN7GT double-triode in the driver stages.

- Minimalist zero-feedback schematic.

- 3 line level inputs (2x3 RCA jacks) selectable via rotary dial on the rear panel.

- High-grade continuosly variable potentiometers for separate (manual) volume control of the channels.

- Ultimate C-Core output transformers (OPT) produced in-house. Precise 4, 8, and 16 ohm loudspeaker load matching via jumpers soldered to the secondary terminals of the OPT.

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

- Ultra low noise mains transformer made in-house for 230Vac (115Vac via jumper setting), 100Vac (Japan), 220Vac (South-Korea, China, Thailand, Indonesia) or 245Vac (Australia).

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

- Nonmagnetic aluminum casework, anodized printing on front and rear panel, powder-coated chassis and lids.

- Dimensions: 150x595xH330 mm,
330=20 (case feet) +210+100 (power tube over case), 595=575+20 (binding posts). Weight 18 Kg. Dimensions of the shipping crate 400x950xH460 mm.


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


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