I have no Dartzeel, Snook2 !
I have just heard it at friend's.
I have the Accuphase P-7000 amp, the Acc C-2400 preamp and the Acc DP-85 CD/SACD.
With Zingali Monitor 215.
I haven't listened to the Dartzel amp with Zingali speakers, but with Avalon.
I too listened to these Avalon with an A-50 Accuphase amp, and I found the sound better : richer and smoother, deeper too I would say.
Question of taste, partly, but we were 3 on 3 people to prefer the A-50.