Ok so after a fresh set of ears there is no difference between .2, .6, 2 or 6V with corresponding increases in preamp volume levels.
Not sure why I’m having a little struggle bonding with my Apex.
Some likely post Covid congestion but also definitely a weeding of listening candidates- which is a good thing. What I’m describing is that incremental improvements in my system has had the effect of laying bare poor recordings. This Apex step has made another swath of recordings dull. The clear and strong recordings shine. A few favorite recordings from previous system are disappointing. This is adjustment is taking some time to cope with.