Well, Dilemma over, I tried the old DAC and it didn't work so all things considered I decided to retire it in favour of the RTZ DAC.
I can't believe how much stuff I'd packed into that case!
All that came out! Pedja Rogic DAC, Hawk Audio class A buffer board, Tent Labs clock, Squeezebox Receiver, many power supplies...
And the almost empty case
End of an era but once I've hoovered the fluff out of it there is plenty of space for the RTZ DAC, power supplies and Lundahl line transformers...
Watch this space!