Introduction The circuit design is modified based on the Matisse Fantasy line stage, comprising of two 12AT7s and two 12AX7s, which, as Matisse points out, breaks no new ground in terms of design innovation. Two amplification stages are configured in common cathode stage with series-shunt feedback. The big improvements come in the choice of component parts and PCB material, circuit layout, and power-supply considerations, all of which are to minimize the influence of RFI.
1. Two 12AX7 and two 12AT7 vacuum tubes.
2.Circuit design with reference to Matisse Fantasy line stage comprising two common cathode stages
with series-shunt feedback.
3. Voltage Gain: 26dB
4. Bandwidth: 1MHz
5. Input impedance: 600kΩ
6. Ouput impedance: 4kΩ
7. Two single-ended inputs and two single-ended outputs.
8. Symmetric layout design and signal paths with minimum parasitic.
9. Dedicated ground and power rails layout design.
10. Two large reservoir decoupling capacitors for power rails.
11. Power requirements: one 420V DC and one 12.6V DC.
12. PCB dimension: 18.6mm (W) x 12.4mm (L)
13. PCB thickness: 2.4mm, double layer, 2oz copper.