Leben CS600 vs McIntosh MC275

Just to let you guys know that I have tried Sovtek 6L6WGC, new reissue Mullard EL34, 6P3S-E, JJ E34L and EH KT90 tubes in the CS600. In my system, the KT90 sounded the best and most balance among all these tubes. The warmness of KT90 complements the natural and neutral sounding M30.1 speakers. The KT90's bass is extended, solid and fast but not too strong. Female vocals sounded sweet. The KT90's high is just right, not too extended, smooth and never fatiguing. No wonder Jeff Day likes the KT90 (http://jeffsplace.me/wordpress/?p=1866). I am very happy with how my system in sounding right now. Not thinking of changing anything for now, at least for a while. One small downside – I wish KT90 has more vocal's baritone. If you know any tubes which sounds similar to KT90 but has more vocal's baritone, please chime in. Probably, I’ll try the KT120 in the future and tube rolls the smaller tubes.

Going on measurements, if the CS600 is anything like the CS300, I would opt for the MC275, it has the far better looking measurements re FR flatness and square wave ringing responses.
The Leben rings like a bell with the square waves and is also shown by it's response which climbs like Everest after 10khz.

http://www.stereophile.com/content/leben-cs300-integrated-amplifier-measurements

http://www.stereophile.com/content/mcintosh-mc275-power-amplifier-measurements

Cheers George

Just purchased a new Mark VI from my friends at Stereo Exchange in NYC. I'm driving a pair of Von Schweikert VR2 loudspeakers through an all solid state Audio Research LS-3 preamp. Pretty sweet. The preamp really made a difference in sounding this amp out.