I am on board with you 100%. If AVA offered a preamp with HT bypass (like in option number 2) and a subwoofer output and passthrough (bypass), I'd sell my Parasound 2100 right now and buy the AVA. I've always wanted one of Frank's premaps, but the missing features listed above are the only things that held me back.
<sigh> Tell me about it... a little while ago I was all set on getting a subwoofer and crossing over sharply at 80 hz. High and low pass filters at 24 db/octave slopes (or 48 db), options for shaping and gain for each, etc.
But... how to do that and to follow the principle of "don't screw things up"? I tried to go there, but Frank would not go there with me.
If you go to all the trouble of putting tubes on your signal path, and eliminating solid-state transistors, then when you do this crossover thing, they might sneak in there... or maybe you will get a passive crossover, which will lead to the usual problems with adding resistors and capacitors to the good ol' signal that you had become accustomed to.
So it seems that we are asking for more or less the impo$$ible, a crossover that does not muck up what Frank has been working on cleaning up for all these years.
Another holy grail here would be a device that takes in a digital signal and performs a perfect crossover service using some math (i.e. no conversion to analog). Then you could not only biamp, you could biDAC.
It is theoretically possible to do so (I think that Gödel proved this as a lemma to one of his big theorems), but as to who has actually done it, the problem is getting those that claim to do so to demonstrate that they are not just marketing BS. There is a famou$$$ preamp that claims to do this very thing, but none of my emails to its manufacturers asking to explain anything about what they are doing has ever received a useful reply. In general, the party line is that such knowledge is what gives them an edge in the market, which of course does not differ from the kind of explanation that a mountebank would give you. Sometimes, Frank will also give such an answer but of course in his case you know he is no mountebank!
