THÖRESS SE 300B Mono Power Amplifier - Pair

SRP: $14999

The SE300B Mono Amplifier is an all-tube power amplifier employing the famous 300B filamentary 300B triode in single-ended (Class-A) operation mode for an output of up to 10 watts into a 4, 8 or 16 ohm loudspeaker load. The power tube is modulated by an extraordinary single-stage taylored around a pair of 2xEL822/CV2382 power tubes operated in triode mode with high idle current. And is combined with a C-core output transformer (OPT) produced in-house to meet the highest possible standards and to perfectly suit the circuit context. These design choices are to a large extent responsible for the richly textured, clear, warm and dynamic sonic presentation of our amplifier.  The SE300B Mono Amplifier is an ultimate component which easily measures up to the highest expectations of even the most critical and experienced music lover. And as such a perfect complement to our DFAmp or FFPre.

BUILT

The amplifier is built with meticulous hand construction using our proven point-topoint 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.

TOPOLOGY

The amplifier is entirely based on SINGLE-ENDED ZERO-FEEDBACK schematics. Decidedly ignoring the fact that many music lovers still 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 are encouraged to read the paper (THÖRESS - Behind the Curtain) downloadable on the ABOUT button of our website.

LOW  NOISE  OPERATION

Specific design choices guarantee low noise operation of the amplifier, even when it is combined with a highly efficient loudspeaker. At first, the 300B triode is DC heated whereas the cathode point of the output circuit can be balanced with respect to the filament of each individual 300B tube by means of a rotary potentiometer. Once the balance adjustment has been made, the signal current is distributed evenly over both ends of the filament and residual hum due to heater voltage ripple vanishes! Secondly, the amplifier has been specifically designed to have a moderate gain (low input sensitivity). This design choice helps to avoid idle noise issues (and ensures conveniently fine volume adjustment) in a wide variety of setup scenarios.

MAINS TRANSFORMERS

The SE300B mono amplifier is equipped with a mains transformer produced inhouse 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 readily customize the amplifier for all kinds of mains voltages, such as 230Vac, 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 classic 300B filamentary power triode in single-ended (class-A) operation mode.
• 2x10 watts of output power.
• Powerful single-stage driver utilizing two EL822/CV2382 pentodes operated in triode mode at high idle current.
• Minimalist (pure class-A) zero-feedback schematic.
• Ultimate tape wound cut core (C-core) output transformer manufactured in-house.
• Precise 4, 8 and 16 ohm loudspeaker load matching via jumpers soldered to the secondary terminals of the output transformer.
• C-core filter choke made in-house.
• High grade foil-in-oil capacitors made in Germany in the power supply.
• Ultra-low noise mains transformer produced in-house for 230Vac, 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 (aluminum) case, anodized printing on front and rear panel, powder-coated chassis and lids.
• Dimensions: 150x595xH330 mm, 330=20/feet+210+100/power tube over case, 595=575+20/speaker binding posts;
• weight: 14 Kg each Mono Block.
• Dimensions of the shipping crate: 950x400xH460 mm.