Description

Valve Pre-amplifier for audiophiles. The idea of circuit topology is based on a so called "CAT SL-1" . However, what we have made is not a clone ! Improvement and changes in circuit have been made in order to achieve much better result in sound. All stages have been re-designed and components values including valves have been re-chosen for more adequate uses. All changes were carried out with the aid of LTspice simulation. The preamp uses one dedicated transformer for high voltage supply and another one just for filament only. High voltage B+ is regulated by a discrete shunt regulator. On the power board, 1X 6X4 NOS Sylvania tube rectifier is used, followed by the shunt regulator providing B+ with very low ripples and impedance across and exceeding entire audio frequency range. Two more separate sets of regulator are also on the same board supplying superior DC voltages for all filament needs. The use of tube rectifier in a full wave configuration produces a feeling of musicality to some extent. Parts used are quality ones like Dale resistors , Solen, GAD-viva, Wima film caps, ALPS potentiometer, Takamisawa relays, and PCB's are 2 mm thickness with 2 OZ copper. All effort in design and construction is to ensure great sound quality and stability. Also added some photos for the reality measurement, showing that, at -3db output, the second harmonic distortion is below -80db, and the rest of are all below -100db . Lower third and odd number harmonic distortion means natural sound without harsh. Valve Tubes: 3X JJ ECC802S New production 1X Beijing 6N11 NOS 1X Sylvania 6X4 black plate NOS Filament : 6.3V DC , 12.6V DC all regulated except for 6X4 Input: 3 sets of RCA input selectable via front knob Output: 1 set of RCA with approx. 100 seconds delay on start up or manual mute via front push button Gain: 16.9db THD+N: 0.019 % THD < 0.016% @ 2.4V RMS Frequency Response: 23.44Hz- 20KHz 0db Power input: AC 230V - 240V Power consumption: 45W approx. Packaging size : 450mm X 390mm X 250mm Unit size: 340mm X 280mm X 140mm Gross weight : 10kg Net weight: 8kg Warranty: 3 years except tubes. 7 Days Trial is available for customers in Australia , Please contact via Ebay message for an arrangement and details.