Mesa Tubes, Colors and Numbers???

[IV]

New to the forum...and what a hell of a forum it is!

I have a Mark IV I have owned 5 years and it came with extra tubes from the previous owner. I have always ran the 6L6s but am experimenting some now with different tubes.

Here's what I have:

6L6GC STR 420s:
-13 NG Yellow (Pair)
-49 TW Gray (Pair)
-21 GR Blue (Pair)

5881-6L6 STR 425s:
-21 MP Green (Pair)

Also have a matched quad of GT EL34s (#2s) I pulled out of my dead Marshall. Lots of distortion from these, which is why I bought them for the Marshall.

Ran the yellow 6L6 Mesas in the inner and the EL34s in the outer (Simul)...a$$load of gain and sounds pretty cool.

My questions:

Sure, the sockets should have matching pairs, but is there a certain configuration we're supposed to run in these amps in regards to color/number?

What do the colors and numbers on the Mesa tubes mean?

Thanks!

 

[Boogiebabies]

They are the natural current draw.

Here is a GT conversion scale from Myles Rose's site.

Mesa scale Groove Tubes scale
Red 4
Yellow 4
Green 5
Gray 5
Blue 6
White 6