martyo,
when i was reading your excellent posting, i felt complete empathy and very strong memories coming back. i went through a very, very similar quest that you did with vmps speakers (rm-40) that i had purchased some years back when vmps was getting a lot of praise and notoriety here on audiocircle. i did purchase them secondhand, but they were mint and there was no evidence of damage or tampering.
specifically, the ribbons were crystal clear, and the midrange was utterly transparent, but i just couldn't seem to have warmth and life into the music that i loved so much. truthful to the recording or not, i still needed to be able to love the music and feel that connection.
and like you've done with the ava / salk reported synergy, so did i start with vmps and the spectron musician iii. i was underwhelmed to say the least. i think the best analogy i can make is that of older hardened glass...clear, but very brittle. at the time i had a wadia 861 se -> spectron musican iii -> vmps rm40, with nordost wiring, bpt 3.5 signature power supply etc...everything that is considered state of the art and neutral.
at that point i realized i could hang up my ego and admit that i do not need a 100% accurately, neutral, system...i just wanted the music to sound so damn good i'd want to keep listening (sober!). i enjoy some bass bloom, and some warmth, and i'll be damned if keeping true to audiophilisms was going to ruin music for me.
so i got rid of my wadia cd player, popped in a modwright tubed output, added a dehavilland preamplifier.
one day, on a whim, i passively biamped my speakers with a gryphon callisto integrated for the bass, since i was missing the warmth and richness from the bottom.
BAM!
the integrated did it. i had excellent warmth and bloom in my room, the dehavilland and modwright tubes did wonders, and steve nugents cables cured any previous hyper-sensitivity i had to the air ribbon tweeter. i was in heaven. my system now measured noticably worse (+/- 12db range in my room, versus +/- d6b before), but now i could fall into radiohead albums, miles davis, and my favorite yo-yo ma bach cello suites once again. i could close my eyes and fall in love with shirley horn, portishead, and yes the greatful dead.
i wouldn't give up on the speakers...the potential is probably there. but i think you had a great idea when you started fooling with the ava gear...maybe you can try biamping passively with an integrated amplifier, so you can adjust the lower frequency response? i think i am fortunate the vmps crossover was at 166hz, so i could really make use of that volume knob on the integrated. i believe the salk crosses over at a fairly low octave as well.
good luck...i'm sure you'll get there.
best,
jp