MA2275 Issue need some advice

Someone else may want to check this to make sure. When I read a schematic like this (lot of parts) from a pdf reader, I get eye fatigue.

Anyway the way I can see is the V4 and V5 are for the phono. They share the left and right half in each individual tube.

The V6 and V7 (gain tubes) also share a left and right in each individual tube.

So assuming the V4 and V5 was physically swapped left to right side (of amp), the V4 and V5 would have should have replaced the gain tubes V6 and V7. I'm thinking the phono (V4+V5) and gain (V6+V7) shouldn't have a bad section on the same side (half) of two tubes. At least it doesn't seem likely, but strange things can happen. A lot of other parts in there. Possibly a solid state part, or other. You could call MAC to make sure also.

The center tubes (V5 to V7) aren't mirrored on top of the chassis, meaning the two on the left isn't for the one channel, and the two on the right side are not for the right channel only.

All of the other tubes (not center four) are for the side they are on I believe.

Link for schematic for anyone else. [http://www.berners.ch/McIntosh/Downloads/MA2275_ser.pdf]

I hope your using other inputs than phono also. And, if it did the same with other inputs, the above would have worked. Otherwise it could be a bad gain, or phono tube if you just used phono in.

The center tubes (V5 to V7) aren't mirrored on top of the chassis, meaning the two on the left

Correction: Should have wrote (V4 to V7)...

I should clarify. Section B of V4 and V5 tubes are for the left channel. Section A of V4 and V5 are for the right channel in these phono tubes.

Section A of V6 and V7, tubes is for the left channel. Section B of V6 and V7, is for the right channel of these gain tubes.

It would seem odd for two tubes to have a bad side. Those two phono tubes are like a spare pair of used tubes, when using them in the other inputs like CD. It still might be worth trying a couple of new 12AX7s. All the other tubes should change the distortion over to the other channel when you switched them, one would think. Did you swap the CD left and right outputs to the amp to make sure the CD player left channel doesn't have the distortion? Or, use another source, like a spare CD player, DVD player, etc. If you did and no changes, I'm thinking repair time. Don't hold me to this though. Anything is possible...