How Soon Do You Realize You Don't Like a Piece of Gear?

@j-wall Most systems, that have no means of loudness contouring, are going to sound too bright when turned up. This is what a system with a reasonably flat frequency response is going to do. The problem all of us face is that the correct amplitude curve is a moving target. I depends on the volume you are listening at and the volume the source material was mixed at. Many older records sound lifeless until you turn them up, way up like the early Zappa and Funkadelic records. 

I suspect your older unit was rolling off the top end slightly.  Anyway, you have two choices, l listen at a volume the music sounds right to you or get a preamp with digital EQ capability. Digital signal processing is sonically invisible. It is the DAC's that sound. "Active" systems are going to be the norm eventually, but audiophiles are extraordinarily change resistant.  

@mijostyn I think I was tolled the Allnic did roll off upper frequencies and did have a darker sound to it, so it could definitely be the VDH not rolling things off and is causing a more honest and strident sound. My room is very small and I am very near field so it could definitely be because the detail is a lot more there and I'm closer to sources with less coloration. I'm curious to see is cabling will impact the power supply and settle things in, but that is for another day at a later date. 

Pretty much as soon as I start listening.  And I don’t buy the “run-in” argument.  If I don’t like it from the beginning, it never changes significantly.

30 minutes. In that time, I would have fixed anything that might affect it, where I sit, what I play, what I might have missed, crossed connections, etc.

Yeah, I would do at least 200 hours of burn-in but it probably wouldn't change your overall impression. Personally, I no longer even consider transistor equipment, well, except for tape decks.