Behringer Ultramatch Pro SRC2496 adding tube buffer

Professional-wannabe Sample Rate Converter, inner ADC and DAC. Here we are adding tube buffer instead of op-amps after DAC chip and change the original XLR analog output to RCA.
SRC2496 includes good Asahi Kasei AK4393 DAC chip and upsampling 24 bit / 96 kHz function.

This is an older generation SRC2496 model (there excists also at least 2 newer models with different pcb's).
SRPP tube buffer and power supply for tubes has built.
Used tubes: 2x 6H6П
Analog audio signal is taken from DAC chip AK4393 straight to the tube buffer.
On the way of the input digital SPDIF signal all intermediate parts are removed, signal goes straight to the CS8420.
Original XLR Cannon sockets from analog output are removed. Installed RCA sockets (Neutrik).
Thanks for ideas: Lukasz Fikus.
January 2014