1. Circuit design is modified based on the classical Marantz 7C, component values are optimized.
2. Three 12AX7B vacuum tubes.
3. Use of WIMA / Solen MPK film capacitors, Nichicon Audio capacitors, BHC Averox capacitors, and Dale resistors. 4. Low voltage dropout regulator LT1085 is employed in regulating power supply for tubes filament, which gives a maximum output driving current of the IC is 3A which is far enough for filament power supply.
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: 110mmx200mm, thickness 2.5mm and 2oz copper, two layers.