It is my DIY PEN45 amplifier in PP operation.

Driver and phase invert : 6SN7 in long tail  pair (one 6S/N7 is good enough for inverting phase and driving PEN45)

Power tube: PEN45 x 4

Rectifier: UU8 x 2

Voltage regulator: 6G6G and VR150

Output transformer ratio: 6K : 16

Negative global feedback: 2%

Amplification class: A

Bandwidth: 20 Hz to 20kHz, +/-2 dB

Power: 2 x 10 watts RMS at 16 Ω

Input level: <= 1V RMS

Input impedance: 100k Ohms

Signal-to-noise: 50 dB

Noise when no signal: 1mV