THÖRESS Full Function Preamplifier MKII

SRP: $13999 The THÖRESS Full Function Pre-amplifier (FFPre) is a versatile vacuum tube device incorporating a state-of-the-art line control amplifier (2x12J5GT tubes) and a ground-breaking phono equalizer (2xPC86 + 2x12JGT tubes) in one case. The phono section is by no means an afterthought or add-on to the line section but a state-ofthe-art apparatus with ultimate sonic capabilities. It provides MC amplification with highly accurate (passively implemented) RIAA de-emphasis and excellent signal-tonoise performance in a purely active operation mode (no step-up transformers involved!). The sonic presentation of the amplifier is of utmost refinement and thus will easily measure up to the highest expectations of every discerning music lover. BUILT The FFPre 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 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. INPUTS The core of the FFPre is a MC gain phono equalizer with three on-the-fly selectable phono inputs P1, P2, P3 (RCA jacks) of equal gain status (65dB@1kHz) yet different cartridge loading characteristics. The phono inputs can be selected on-the-fly with the source dial. Alternatively, the FFPre is available with MM gain phono section (45dB@1kHz). The standard cartridge load pattern on the phono inputs of 3XMC and 3xMM sunits are (P1, P2, P3)=(100, 200, 500),   (P1, P2, P3)=(47K, 47K, 47K) respectively. Other cartridge load values can be easily installed on request. Notably, it is not possible to implement MM and MC phono gain simultaneously for technical reasons! Furthermore, the amplifier offers three line inputs (RCA jacks) with different gain and input impedance characteristics as described below. Medium Line Gain on Input #6 The gain on input #6 is 26dB (20-times). This input has a comparatively high input impedance of 80.000 ohms and is suitable for classic line level program sources such as phono pre-amplifiers, tape machines or tuners. Low Line Gain on Input #4 and #5 Inputs #4 and #5 offer a gain of 18dB (8-times, 18dB=26dB-8dB) and are meant for modern high-output digital sources such as CD/DVD players, DACs and streamers. The input impedance on these inputs is 30.000 ohms. Summarizing, the standard gain pattern on the inputs is (MC, MC, MC; 18, 18; 26) dB,   (MM, MM, MM; 18, 18; 26) dB on 3xMC and 3xMM units respectively. Other gain patterns can be easily implemented on demand. For example (MC, MC, MC; 10, 10; 18) dB, or   (MM, MM, MM; 18; 26, 26) dB. OUTPUTS OUTPUTS The line section of the FFPre terminates in a twin output (2x2 RCA jacks pairwise connected in parallel). It is thus possible to simultaneously drive a power amplifier and an active sub-woofer without further adaptation. The twin output is also useful for proper dual-channel mono playback installation with SINGLE-COIL phono cartridges as described in the user manual. The output impedance of the line section is sufficiently low (300 ohms) to drive long cable runs and an input impedance as low as 10.000 ohms without compromising sound quality. The 3dB-down frequency of the response is still well below the audio band (lower than 5Hz, 3.3MFD output coupling capacitor) under 10.000 ohm loading conditions. The FFPre also comprises a pass-through output (QUELLE) for the activated programm source. If one of the phono inputs is switched active the (amplified and equalized) phono signal is forwarded to the pass-through output. Such the phonosection of the FFPre can be tapped and combined with an external line control amplifier or integrated amplifier! VOLUME CONTROL A pair of high-grade continuously variable potentiometers is employed for separate MANUAL volume control of the channels. These parts are made to our taper specifications (by ALPS in Japan) so as to allow for conveniently fine volume adjustment. Each pair of potentiometers is hand-picked from a larger production batch by careful measurement to ensure matched attenuation characteristics with respect to angle of rotation. Consequently the volume knob scales are a reliable reference for channel balance adjustment. Notably, it is not possible to install remote volume control on the FFPre! Music lovers who consider remote volume control as an indispensable feature are encouraged to take a look at our Dual Function Amplifier or the EHT Integrated. MAINS TRANSFORMER The FFPre is equipped with a proprietary mains transformer produced in-house to ensure the highest possible quality. This part has been specifically designed 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 for 100Vac (Japan), 220Vac (South-Korea, China, Thailand, Indonesia) or 245Vac (Australia). FEATURE OVERVIEW                 Reference grade vacuum tube line control amplifier and state-of-the-art vacuum tube phono equalizer within one chassis. Purely active MC gain phono section (65dB@1KHz) with excellent signal-to-noise performance (no built-in step-up transformers). Alternatively, MM gain (45dB@1KHz)  can be installed in the phono section on request. Highly accurate RIAA equalization (passive de-emphasis implementation). Minimalist single-ended zero-feedback schematics throughout. Six inputs (3xphono + 3xline) with gain pattern (MC, MC, MC; 18, 18; 26) dB. Channel-separate manual volume control via high-grade continuously-variable rotary potentiometers with low angle sensitivity (conveniently fine volume adjustment). 2x line outputs with low output impedance. Pass-through output for the active input. Ultra low noise and 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. Nonmagnetic aluminum casework, anodized printing on front and rear panel, powder-coated lids. Dimensions: 434x434x154 mm, 154=134+20 (feet). Dimensions of the shipping box:  650x650x350 mm, weight 11.5 Kg.