$6000 Budget Which used Amp ?

Mp is right. Give your Logans a listen with both solid state and high powered tube amps and hear the difference for yourself. They really open up with tubes. Tube amps are also better able to deal with the sometimes interesting impedance swings that these speakers can produce.

By the way, you didn't mention which Martin Logan speakers you plan on using. Are you driving Statements, Prodigy's, CLS's, etc. -- it will make a difference in recommendations although conceptually I think tubes, (or a combination of tubes and solid state), are still the way to go whatever the model.

Go listen for yourself.Take amps home to listen.

My Quest Z's sound great with my BATVK500, much smoother than with my Classe. I'd suggest a tube preamp and transistor amp, BATVK30 and VK500 are great in my setup. I've stayed away from tube amps, mostly due to the cost of changing tubes. I leave my stuff on all the time, tubes would need replacing fairly often and output tubes aren't cheap.

How about Sonic Frontiers Power 3? I was looking at both the VT200 and the Power 3. I found the Power 3 with a 5-year warranty here on Audiogon (Underwood Wally 770-667-5633, great guy) for a lot less than the VT200 used. The sound is very good with my B&W 801s.

I have Pass Labs X350 driving ML reQuests with MIT 750 Shotgun cables with great success. Very smooth and detail.

I may consider selling my X350 (1 year old in perfect condition) because I move all my equipment to dedicated HT room and will probably go for multichannel amp. I hate to depart with this amp, and may just add another multichannel one to drive other speakers - have not decided yet.
I will decide within a couple of month though.

If you are interested, contact me (732) 617-0927
or email to roman@insightfirst.com

AOB
Roman