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Calling all MC275 MK IV owners..............

I just set up my new MC275 and although the tubes have about 90 minutes on them, I'm blown away by the sound - I wish I discovered tubes 10 years ago.

Anyway, a few questions:

1. What gain level do I set the amp to. I cranked it all the way up but is there an "optimum setting?" I'm running these in stereo mode with unbalanced connections.

2. In a couple of days another MC275 gets delivered and I plan to run them in mono mode also using unbalanced connections. What gain setting is optimal for that configuration?

3. I have the amps on a trigger switch and noticed that on power up the tubes sort of glows a bit brighter for a second then settles back into the normal orange filament glow. is this normal?

4. What is tube rolling?

Thanks for all your help. I really appreciate it. Sorry if these questions are a bit stupid.
pookie10

Showing 2 responses by pookie10

pookie10's avatar
pookie10 OP
41 posts
 
Thanks for your answers. I think I will just relax now. The rest of my system is:

B&W Nautilus 804 (MC275 will drive these), HTM2 center and a pair of SCM1s.
I'm using the MIT Magnum 3 for the fronts and cheapo wire for the rears.
All hooked into a McIntosh MHT20 via Synergistic Reaseach Designer Reference interconnects.

I'm at a crossroads where I have to decide if I'm staying with 5.1 or going back to dedicated 2-channel. If I went back to 2-channel I would get the C2200 pre-amp but I'm concerned that tube on tube might get to sonically hazy or muddy.

To be honest, I'm pleasantly surprised at the MHT200's performance as a stand alone pre-amp. Granted my expectations were low to nil but it would stand up against many dedicated pre-amps.
pookie10's avatar
pookie10 OP
41 posts
 
More tube questions............just received my "back up" set of output tubes. 8 Winged C KT88 tubes. 6 of them have a bias of 45 and 2 have a bias of 44. According to the McIntosh literature, the MC275 is self-biasing. Since I have NO IDEA what ANY of this means, is it a problem that 2 of the tubes are "off" by one unit?

Also, the small output tubes say 12AX7A but all I could find are 12AX7 (no A). What is the difference?

I'm also looking for input tube recommendations. I'm running both in mono using the RCA inputs.

Thank you again for your help.
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