Tube layout/placement?

[HSL]

I just got a 3-channel dual rec. The manual is confusing.

2.) Slowly bend the spring steel tube clamps on the two (or three) far right (when viewing amp from the rear) tube sockets up so that the tubes will have to push the clamps open slightly as you install the tubes.

The next line says this:

3.) Install 5U4 Rectifier tubes in the far left (when viewing amp from the rear) tube sockets being careful to line up the guide pin on the tubes base with the slot in the respective tube socket. Then gently rock the tube back and forth while pushing downward on the tube until the tubes are seated.

So which one is it? I went against #3 and put two of the 5u4 tubes on the far right when looking at it from behind since that's what I see in pictures on Google. I also noticed that you have to flip the manual to see it right since the text is on the outside of the preamp tubes.

PS: I read somewhere that you need 'matched' tubes, or something. I just popped mine in randomly since they weren't labeled. Do I need to worry about this?

 

[domct203]

When viewing from the rear, the rectifier tubes are on the far right in the amp heads.

Power tubes need to be matched for idle current draw (bias). If you have Mesa branded tubes the matching is done with a color code (YEL, GRN, RED etc) printed on the label on the tube's base. Tubes are matched in pairs, and in the Dual Rectifier it is an outside pair (X) and an inside pair (Y) ie. X-Y-Y-X.

Rectifier tubes (5U4GB) do not need to be matched.

Dom

 

[HSL]

All of the 6L6 tubes I have have GRN printed on them, so that's a total of 4. Is that good or bad? I just popped them in in any order. I'm also guessing this doesn't matter for preamp tubes. Am I right on that?