This is the Satch DAC assembled with the Universal tube output stage already installed. It includes an Tesla ECC88, silverplated RCA's. the input board is bypassed in this case the op amps mounted on the daughter card are not used. This tube stage is not a buffer or a cathode follower. The output is taken from the anode and is a hybrid anode follower. Output impedance is around 75 ohms with this implementation.

note: tube rings not included