I have an ARC SP14 also and really like it, but remember it is a hybrid and the only tube is in the phono stage. So when your line stage is activated, you are solid state all the way. Move the Logans out into the room as far as you can and away from the side walls. If you can, use spikes to couple the speakers to the floor. Also experiment with toe-in and tilt back. Martin Logans are a pain sometimes to position correctly and suffer from the "venetion blind effect" to a certain degree.
I promised myself I'd never do this
You know the threads, where people ask for help matching this speaker to that amplifier (s)? Always seemed like wasted space in a lot of ways to me, but here I find myself pondering which way to go with my system. So, I break my own golden rule, and ask for your advice. The system: Oracle Delphi IV/SME345/Grado Reference, Magnum Dynalab Tuner, YBA CD Integre CD player, Audio Research SP14 Preamp, (2) Classe Audio DR8 amplifiers in bridged mode, Martin Logan Quest Z speakers bi-wired. Various quality IC's and power cords. I'm considering changing the amps, primarily due to a "live" listening room that would benefit from a more mellow sound, and the amps have more power than I'll ever need. Treating the room is out of the question, lawyers cost more than my rig. Naturally tubes come to mind, but the care and feeding of tube amps can be significant, solid state are plug and play and forget about 'em. I'd likely be looking to spend around $3k for a used amp, any suggestions on where to begin? Thanks in advance to any of you who take the time to respond, Jeff