Tube PCB with 10mm Standoffs (10mm standoffs are required and 10mm clearance must be present below the PCB):
Fixing holes in the four corners on a 71mm X 131mm rectangle. Fixing holes require M3 or equivalent screws.
Fixing with either central M4/M5 bolt or via 4 racetrack shaped 8mm X 5mm Holes centered on a 60mm square.
This means for the mains transformer to fit at least 40mm clearance above it is required, the tube stage needs 45mm.
(example only as will vary by implementation):
measurements Iout DAC Mode (=30db gain)
referenced to 2V RMS, Saratov (Reflector/Sovtek) 6N23 fitted
Measurements vary with different tubes fitted
● S/N- > 100dbA (approx 5nv/hz).
● THD- <0.15% (<0.1% typical); <1%THD (10Vout, 100K load)
● 20Hz – 20KHz (< -0.5db with IHF 10K/1nf load)
● Output Impedance <100 Ohm
● Can use 6cg7, 6N11,ECC 88, 6DJ8, 6922, 6H1 only