Responses from triode

Avantgarde Uno/Duo
Whart and Inman29 have pretty much nailed it, but with proper setup (including minimum 12' distance from listening seat to drivers) the integration is a non-issue (I have Duos which I upgraded to Duo Omegas) and the active woofers have level and x... 
Budget Pre with 2outputs, rectifier tube and.....
Tube rectification RULES. 
Best 845 SET mono amps?
I once heard some spectacular 845 monos designed by Yori Komuro, who now does the amp design work for Absolare. Have not heard them, but the word from shows and reviews seems uniformly promising.Other options are Cary, Mastersound. 
Suggestions? Tubed linestage pre-amp??
I second the Cary SLP-98! 
Looking for Help - LS27 or SLP-05
My SLP-05 is a treasure. It uses 6SN7s (I imagine the ARC uses 6922s or 6H30s),which to my ears is generally a "ballsier", richer, bigger sounding tube - particularly in this circuit, but without sacrificing air or detail. It sounds as if this may... 
Looking to re-build my system.... Cary SLP 05
I love my '05 with NOS Sylvania 6SN7s and NOS Philips Holland metal base 5AR4. I run mine single-ended so only need 4 premium 6SN7s, just left the stock EH tubes in the balanced output and headphone amp positions. 
Pass Labs amps and Avantgarde speakers
To say that one needs 20 wpc on 107dB sensitive Duos is...misinformed. I can run mine on 3.5 wpc 2A3 amps with plenty of headroom; it's just that qualitatively the Lamms are the best I've heard to date, at 18 wpc. 
Ssssh, is your tube preamp really that quiet?
Cary SLP-05 is dead quiet through my 107dB sensitive horns (via Lamm ML2). 
Of all your gear, what piece impresses you most?
I have to cop out a bit here, and declare a tie between my Avantgarde Duo Omegas and my Lamm ML2s - the synergy between these components is priceless.Not so far behind: the AMR CD-77.1 CD player, and the Cary SLP-05 linestage. 
Pass Labs amps and Avantgarde speakers
I've tried 300B and 2A3 amps with my Duo Omegas - both far outclassed by the Lamm ML2. Even at 107dB sensitivity and with powered subs, the Lamms make a huge difference in bass performance (taken at speaker level, not line level), musical flow, de... 
Avantgarde Duo Omega
Mine are in a 14 x 17 room, which I agree is an approximate minimum. You want to sit 12' or more from the drivers for proper integration. Mine are best with 10' between the tweeters at a listening distance of 12'. 
Preamp Noise with High-Efficiency Speakers
I too have super sensitive Avantgardes (107 dB Duo Omegas) and run a tube pre and tube amps (as well as an AMR tube CD player, and analog with tube phono stage) with virtually zero noise - one must put their ear right up to the tweeter horn to hea... 
Need help with a Tube PREAMP.
Given the input impedance of your amp, a tube pre with balanced output capability is probably your best bet. Definitely check out the Cary SLP-05 if in your price range. 
High powered amps for low sensitivity
This is a perverse quest. High sensitivity/low power is the goods - do you have a friend who can let you hear such a rig - you may never go back... 
Avantgarde Duos: Omega or Mezzo?
I second Maril555's recommendation of the Lamm ML2; magic combination with my Duo Omegas!