OVERVIEW
The circuit design is referenced to Grounded Ground preamplifier which can be found in earlier wireless radio applications which requirie to meet high signal-to-noise ratio (SNR) and wide bandwidth requirements. For audio application, it is capable of creating high dynamic responses and quiet background which perserves the originality of the beauty of audio signals with neglectable distortion due to the simplicity of the circuits. Also, thanks to the differential pairs of the input stages, it rejects most of common-mode noise and has high PSRR. This grounded grid (GG) preamplifier will not make any artifacts to the sound and play 100% originally and naturally.
2. Three vacuum tube 12AU7 for amplification.
3. Use of Solen / WIMA MPK10 capacitors, Nichicon FW capacitors, Philips/BHC Averox capacitors, and Dale resistors.
4. Built-in rectification and regulation circuit.
5. Dedicated power and ground rails for tube power and tube filaments.
6. Symmetry in layout design for both channels.
7. Power requirement: one 200V AC(100mA) and one 12.6V AC (1A).
8. PCB dimension: 111mm x 220mm, thickness 2.5mm and 2oz copper, two layers.