Mesa tube color grading...

What is the succession of colors from lowest (early breakup) to highest(late breakup) ?
Just a wonderin'....
ax. 8)

Red = 4
Yellow =4
Green =5
Gray =5
Blue =6
White =6

numbers represent GT scale. 1=earliest;10=latest (breakup)
Mesa considers 4 to 6 safe (but not covered under warranty) on the GT scale.

I'm fairly new to mesa's (I've had an LSS for about a year). My tubes don't have any color on them. The lettering is in black. Is the color coding just for 6L6's?

i believe the colour is actually written out..."red", rather than printed in any colour.

I'm guessing that EL-84's are not color coded--there are no colors or words to that effect on any of the EL-84's I have.

All they have on them is "6BQ5" "Mesa Engineering" and "EL-84"

you are correct there. the colour codes are on the black base of the big bottle tubes. since el84's are cathode biased in all mesa amps, there is no need for a rating system.

here is an example of a mesa tube. the colour coding is on the silver ring of the black base.

http://us.st11.yimg.com/store1.yimg.com/I/mesa_1880_277635

MesaDCLP said:

Red = 4
Yellow =4
Green =5
Gray =5
Blue =6
White =6

numbers represent GT scale. 1=earliest;10=latest (breakup)
Mesa considers 4 to 6 safe (but not covered under warranty) on the GT scale.

Click to expand...

I have a Messa Boogie MKIIb that I've owned for number of years, & am getting back into playing more seriously after a long hiatus. This amp kind of always sounded a little odd, but after reading this post I thought I'd check the output tubes. It had a pair of Groove tubes marked "H1"!

I guess I am to assume that....

A: The last person who put output tubes in this amp (before I owned it) was a jackass, and thought any tube would work...

B: Actually prefered the sound of having ouptut tubes that were out of Mesa's specific voltage range....

or

C: This amp was modified by having adjustable bias pot (which, being a layman on tube electronics, would be very difficult for me to check if that was done.)

I'm hoping the case was either A or B. Assumeing that the original fixed bias is still intact on this amp, could there be any damage done as a result of having these tubes in there?

I'm really glad I found this message board, I think it should be required viewing for all Mesa/Boggie owners