You might be getting that result, but it's not the 275's fault. More info is needed -- preamp? speakers?
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mcintosh products are not lush.
i just finished an audition of the c 220 (tube) preamp and i own the 275. if you contact the company they will tell you that the design goal is one of neutrality.
it is possible that the probablem you are having with the 275 is the stock tubes. they are horrendous.
i would like to replace the kt88,s, but am not sure what to replace them with. get rid of the 12ax7 tubes and 12at7 tubes, and experiment with nos tubes.
Lovepianos, Tennis is quite right about the stock tubes (horrendous ;--) But they're not so bad you couldn't enjoy the amp's wonderful attributes. If your result is missing both image (higher freq) and bass, I'm inclined to believe there might be an impedance mis-match between the Rotel and the 275. That said, the 275 has a fairly high input impedance (I think! It doesn't say in the manual) and should accept most preamps.
If you want to try other tubes, see my report on tube rolling w/ the MC275 at:
you have more experience with this amp than i do. i have about 25 hours of use. how does the amp change, sonically, over time ?, after 300 hours, does the amp sound more robust, with less treble emphasis.
what about the tubes, you mentioned a bunch of 12 volt tubes, without specifying what you or your friend's experienced with each tube.
i would like to reduce the treble energy and get more emphasis upon the upper bass and lower midrange, as well as create a more distant presentation. any ideas ?
Tennis, the most sonic bang for the buck is replacing the 12AX7's -- V-1,2,5. (If you run balanced, V-1 is out of the signal path, that's why I asked ;--) For a beautiful, well rounded sound with air, sparkle and detail, I'd recommend Telefunkens. If you want a little more dynamic, muscular sound (but still refined) I suggest the RCA blackplate-longplates.
If you want to change the 12AT7's V-3,4,6,7, I'd suggest Telefunkens (RCA's there are a bit too much of a good thing.) If you want to change the power tubes, the KT88's, either the Penta KT88SC's or the Russian re-issue Gold Lions seem to be the most popular. Both provide a little more power and dynamics. I prefer the Pentas.
i am not looking for more dynamics, detail or sparkle. i am looking for a more euphonic sound--laid back, attenuated on the top and a peak in the upper bass/lower midrange. think slow and syrupy.
i bought the amp because i need power. however, it seems to be too "neutral" for my taste. is there another set of kt88s i could use ?
Tennis, I'd leave any KT88 changes for last (if at all). Now if what you're after is slow and syrupy (we say 'schmaltzy' in my neighboorhood ;--) I think you can't do better than NOS Mullard 12AX7's (the UK ones, not the Holland ones). And if you like what they do in the AX spots, and I think you will, I have 2 matched pair of Mullard 12AT7's I'd be willing to offer you. I don't have any Mullard 12AX7's unfortunately, or I'd let you try a set.