Mixed driver tube for Mcintosh MC275


I just wonder if anybody know which sections of Mcintosh MC275's driver tube are most crucial? Is it all sections of equipment are the same in terms of the importance of the driver tubes. Another thing, is it using a tube that has a sonic trait that is different than another like combining a thinner more detailed tube like a Telefunken can actually work very well with a warmer tube like a Mullard?
yewhlock
Tzh21y -- if you go to the Cardas website >> products >> speaker cables >> Golden Presence, you will see that speaker cable has a capacitance of 168 picofarads/foot. Just as a reference, the maximum suggested capacitance for electrostats is around 20 pf/ft. Which shouldn't be a big factor with your Merlins, which use Israeli Morel cones/domes anyway. However, most Cardas speaker cable is 350-450 pf/ft, and because I personally believe this is, well, not a 'good' thing (and is pretty much a uniquely "Cardas" characteristic) I always recommend to people using Cardas speaker cables that they experiment inexpensively by picking up some insulated solid copper 10AWG wire at Home Depot (poor man's Anti Cables, and just the opposite characteristics of Cardas!) and doing an A-B. You might be very surprised, and it will only cost you a couple dollars and a little time. If I were you I'd do this speaker cable experiment first, and hang on to the Cardas IC for now. If you like what the Home Depot wire does, you can get some Speltz Anti-Cable speaker cable (but mid-priced Virtual Dynamics solid core would be better ;--)

The RCA 17mm longplate, blackplate 12AX7's are one of my favorite 12AX7's They have a lot of balls, and if you use them in the V-2, V-5 spots, you don't want anything too strong in the 12AT7 spots or the sound will be in your face! Tellies and/or Mullies would be fine for the 12AT7's.

For phono stages, unless you're using a very low output MC (like .2mV), my favorite 12AX7 is either a Sylvania or RCA triple-mica blackplate 5751. Very quiet and SMOOTH sound (no rough edges like almost ALL 12AX7's ;--) and they always seem to have closely matched triodes right out of the box. Of course they'll cost between $150 and $225 a pair these days! I have some of those too ;--)
Maybe I will try the RCA's in the phono section. The tellies are quite good and very neutral.
In simple audio language, the more expensive tube is usually the better tube. If you have a Ferrari, use the best tires you can afford. Same for a McIntosh MC-275... 
Hi, I have a similar question.  I have a pair of Telefunken 12AT7 and a pair of Mullard 12AT7, where should I put them?  In the first response, it seems to suggest V3,V4 should match and V6,V7 should match.  However, from other places, I read that V3, V6 are output drivers, one for each channel.  V4, V7 are cathode followers, one for each channel.

In order to balance left and right channel, does that mean, I should put one matched pair In same brand in V3, V6; another matched pair in same brand in V4, V7?