EL34s in Mark IV?/Mesa's Color Coded Tubes

ATTENTION: Tube Gurus!

Issue: I've been wanting to try EL34s in my Mark IV.

Question #1: I'm sure most of you are familiar with the way Mesa assigns a color match group/code to their tubes. Is one color/code better than another? Green, yellow, red, etc.

Question #2: Of all the EL34s that Mesa offers, which STR version would you recommend? Right now I'm juggling the STR-442 Svetlanas, and the STR-447 Sovteks.

I haven't tried EL34s in my Boogie. I'm just too happy with the 5881s.

You other question though...

As I recall, the color is only for matching within a set to make sure that a set of power tubes is all in the same range.

So yellow, goes with yellow, green with green, etc.

Other than that, I haven't changed power tubes through enough different sets to comment on relative virtues of different colors.

The colors probably have a numerical value though...hmm anyone know?

As far as the colors having a meaning....Yes, they do have a numerical value. Here is a little bit of information.

Lower numbers will start to distort at lower volume settings on your amp, and have
more dynamic touch and feel. These are the GT 1-3 range, and the Fender "blue"
painted tubes. Many Jazz or Blues players like this range, and they work well for
recording where levels are going to be lower, or in smaller venues.

Medium numbers are the most versitile, will drop into most amps and be very close to
most factories bias settings, and are the best general choice for most players wanting
a versitile well rounded amp. These are the GT 4-7 range, and the Fender "white"
painted tubes. The range of 4,5,6 are able to be used in Mesa Boogie fixed bias
amps, and on the Mesa scale convert roughly to:

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

High number will have to be driven at higher volume levels to begin to reach output
stage distortion. These are liked by some Jazz players that want a very clean sound.
They are also preferred by some heavy metal folks, who want very clean high
headroom. These folks like to get most of their distortion from front end effects,
pedals, or by running their preamp levels very high. These tubes have the least
dynamic touch and will give the most clean headroom. These are the GT 8-10 range,
and the Fender "red" painted tubes.

With all of that in mind, the tubes Mesa sells run cool to hot in the medium range. The coolest are the Reds and the hottest are the Whites.

Dale

I recently purchased some Svetlana EL34s (rated for Boogie Mark IV) from TheTubeStore.com, and so far I'm kind of liking the sound of them in my Mark IV. Although I'm having a hard time cleaning up the sound of the lead channel. I'm still a rookie at dialing up tones in this amp, so it's probably just my own settings.

I hear ya. The Mark IV can be a little tough to dial in, as you have all of those different belles and whistles that effect the tone. That amp is mainly centered in through the high end. Running EL34's in the outter sockets will enhance the highs and high mids, so you might want to back down on some of your settings if you don't like what you're hearing.

Another thing to consider is that the initial change in the tone might disturb you. It may take a few days to get used to.

When I ran EL34's in the Mark IV that I had, I didn't really like what they did to the clean channel. I preferred running all 6L6GC's in the amp. JJ's were good for that Laser Beam punchiness and SED's were good for a smoother, more refined vibe.

Dale