Mesa power tube color codes?....

I need an education on Mesas power tube color code system. From what I understand they rate from coldest to warmest in this order......

Red
Yellow
Green
Gray
Blue
White

So if I'm understanding this correctly, Red would give the most clean headroom while White would break up sooner. Which brings me to the question....will White bring up the bias and warm up the tone? Or does it just apply to headroom only?

good question...also which works best in a rectifer?

Kung-Fool said:

I need an education on Mesas power tube color code system. From what I understand they rate from coldest to warmest in this order......

Red
Yellow
Green
Gray
Blue
White

So if I'm understanding this correctly, Red would give the most clean headroom while White would break up sooner. Which brings me to the question....will White bring up the bias and warm up the tone? Or does it just apply to headroom only?

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The Red's and Yellows are so cold they may only draw between 15-20ma in a DR or any other 4 6L6 Mesa at -52V. The Green to White have higher natural plate current and draw more bias. They incrementally go up by a few MA's until you get to White. Even the white lables will usually only get you to 50-60 % MPD. More or less, they are safe to run in any Mesa. The only difference you will have to be careful is in Simul-Class amps. Both 6L6's and EL-34's above green may run too hot and wear quickly and die, or poof out. I have basically tried every Mesa color code with a Bias meter to see how they draw out.

Boogiebabies said:

The Red's and Yellows are so cold they may only draw between 15-20ma in a DR or any other 4 6L6 Mesa at -52V. The Green to White have higher natural plate current and draw more bias. They incrementally go up by a few MA's until you get to White. Even the white lables will usually only get you to 50-60 % MPD. More or less, they are safe to run in any Mesa. The only difference you will have to be careful is in Simul-Class amps. Both 6L6's and EL-34's above green may run too hot and wear quickly and die, or poof out. I have basically tried every Mesa color code with a Bias meter to see how they draw out.

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Awesome. That's exactly what I was looking for. Thank you sir!

I called Mesa a couple of months ago to ask them what the deal was with the power tube color codes and they told me that the color codes are just production batch #'s and don't relate to bias or tone.

I just found this on this quote on the Mesa web site that seams to confirm what he said:

"Mesa/Boogie tubes have a three letter color code at the base of the tube used to group the tubes into matched pairs. These color codes do not apply to different tonal variation (the number and two letter codes with the color code are Production Batch #'s and Tester's initials respectively). "

Now I wonder what the truth is.

the truth is that all colors can be used in mesa amps. at stage volume they hardly differentiate from one another. however, the "feel" structure of the gain might be slightly different, but it will be noticeable only depending on music that is played and picking style. if you are in metal business, then more gain will give you a better feel, because you will perceive aggressive chordes as fast playing. if you're in clean or bluesy business, the hot gain structure will not be so much perceivable. in the end, at stage level, they are all almost the same. the gain structure has a more audible spectrum at lower volumes, but there you don't have the full amp's tone.

so, the change is not so proeminent as when you switch from 6L6's to EL34's. here is a much different story and you may need to reshape the gain/tone to suit your needs. I've recently found the taste of Yellow EL-34 in Mark V. now I can push more bottom end and less top without affecting gain structure so much, yet the fast response of the amp yelds a tone that is really cutting through. maybe not so smooth as 6L6's, but that shouldnt be read as roughness - is a more woody tone, with less buzz, at high gain, that is. Today I like it over the 6L6, but I will see how it goes after a few weeks and maybe some recordings.

The Mesa guys who are saying 'no difference' simply don't know their product. Its the dumbed down answer that the marketing department must tell them to say. Because for 90% of guys who sit in their bedroom and use 2% of their amp's power capability, true it doesn't make a difference.

But for gigging musicians who play small arenas and auditoriums with loud drummers, there is a big difference.

I've found significant tonal and feel differences between yellow and green, for instance. Yellows will break up at volumes you would typically use on stage. Greens have quite a bit more clean headroom. Since I'm into more vintage power tube coloration, I prefer the yellows.

There's a good animated demonstration on one of the tube vendor sites that shows the affect of bias voltage on the headroom characteristics of power tubes. Basically there's one bias voltages that maximizes the clean headroom power output of any given tube. But since tubes are all different, in aggregate there is a statistical distribution of bias voltages across a large set of tubes.

Since mesa is fixed bias, the maximum power output with that preselected fixed bias voltage only occurs with a narrow range of tubes, I'd guess the center to correspond slightly to the right of green, and all the rest are biased colder or hotter than optimal. This imparts a slightly different tone and considerably different clean headroom characteristics, accordingly.

Yellows all the way for me, for more marshally type power tube crunch, anyways.

http://mesaboogie.com/news/2012/03/mesa-tube-color-codes-by-randall-smith/?utm_source=Mesa%2FBoogie+Amplitudes+Newsletter+List&utm_campaign=b7a765dcb0-Amplitudes_March+2012&utm_medium=email

They lop off the extremes, but they are still trying to match for variability. Maybe the tone isn't a lot different,but the volume you must play at to get that tone definately varies.

The difference between yellows and greens on my Nomad was spectacular. So, it matters.

I called mesa, they still use color codes but suposedly they dont really sound different, might me a marketing strategy to say this, tough.. Different colors can also be used together in pairs i was told.

Mesa's #1 concern when giving tube advice is liability. They don't want to give advice that could damage your amp.

Tone is very subjective, so they have probably had to limit discussion of it for their own sanity.

When I called to find out about getting my IIC serviced, upgraded, we talked tubes. I was advised yellow for more headroom, and I get to 3 on MV oncemina while, and it does seem more clean punch available. New tubes helped too. At the end of the dy having matched pairs to plug and play is cool.

I'm glad Mesa gives a **** and tries to help me find my tone. Marketing guys? Ummm... They may not be the best source of technical info, just sayin.

I'm having trouble dialing in a good tone on a Nomad 100 I just bought. I replaced the old mixed tubes it came with for a quad of MB 6L6 yellows. It sounds very grainy and muddy still. I've been told from a reliable outside source that the Nomad specifically sounds best with blues or whites. So, it seems that althought the MB tubes are plug and play, the color makes a difference based on the amp you have. I'm tweaking the preamp tubes now and I will eventually replace the power tubes again, most likely with EH 6CA7 (EL34). I agree that MB has very stock answers when it comes to tubes and they won't help you explore outside the MB tubes, I'm sure for financial reasons - they want to sell their own label on the tubes you use. Has anyone used the EH 6CA7 with success in a Mesa? MB told me not to use them since they haven't tested them, but other techs have said they are the same as EL34s and should be fine.

I stick to the color codes on my tubes to keep the same tone that I fell in love with on my amps. Don't want to chance, changing the tones I like. My Express 5:50 has Yel. 6L6 tubes, F30 has Gray EL84 tubes and my F50 has blue 6L6 tubes. I guess its fine to change power tubes as long as its a matching set, but I invested to much money in my amps to take a chance. Great information on this post. Thank-you.