Tube-I-zator SRPP DAC I/V-Stage circuit discussions

[schubert]

I'd like to use one of these boards in a Sony CDP-710, but I'm having trouble figuring out how to implement it. I'd have to use the V-out version because the separation of the audio signal into right and left channels appears to occur after the DAC in analog by means of a MC74HC4053N chip (see attachment). Therein lies the problem - the MC74HC4053N signals are combined with the signal from the DAC (L+R presumably, since there's only one) after the op-amp, which I think is set up to invert the signals from the multiplexer. It looks to me like L-R and R-L signals are generated in the multiplexer, and the DAC mono signal is subtracted from them to get R & L. Can the SRPP circuit be used in this hodge-podge? If so how would it be connected and which tube would work? I'm rather new at this stuff and so far I just know enough to be dangerous. Any help would be appreciated.