@lewm : It's way " pity " ( for say the least ) that all the other owners that already posted in this thread just let you ALONE in the discussion.
My take for that is that all them do not care if the design is totally wrong but that they like it as you but exist a " but ": the difference between you and all them is that you are the only that like it but even that you are looking why a wrong design like it. Yoi are chasing " explanations " as the ones you posted and that rpoves nothing in favor of what you are looking for.
Again, instead to " lost " some timie posting here use that time to develop a sure/true test overall proccess as I did it 20+ years ago
Lew, how can you explain it that two audiophiles as José and I could designed the Essential 3150 unit is high quality reproduction levels with out resources as true audio electronics manufacturers. Because José and I are only two people appasinated with MUSIC and MUSIC reproduction at home and not in the audio market, this was at " random "?
Yes, technically José is very good but it's not enough to make the design because that design must be voiced in high resolution rooms/systems and that voicing mainly belongs to me.
The developed tests proccess permited us to choose between diferent manufacturer transistor models/resistors/capacitors/ and the like ( obviously that were several kind of measurements on all those ) and after test the " rigth " parts the need it to beeen assembled on the boards and after that to make " thousands " of listening tests in different room/systems. With out that proccess we just can't made it with that quality levels.
But after the Essential 3150 came the Essential 3160 that you own ( so you know exactly what I'm talking about. ) and rigth now ( with out be conceited ) the Essential 3180 that beats the 3160 and almost other unit in the today phonolinepreamp market and a serious challenge for any today market unit. You name it and can be sure that overall can't beats the Essential 3180.
That's why I insiste in your proccess developing with or with out the VIV subject.
R.