Mesa power valve colors meaning?

[Luca79]

Ask for a friend... his Mark V had RED tubes and the tech installed a new set of GREYS (4 power tubes). Is this fine? Or he had to get RED tubes?

 

[SpiderWars]

I would think @psychodave would know this firsthand since he's had a ton of Mesa amps and has a good tube tester.

 

[psychodave]

This is from Miles Rose:

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

Mesa Red tubes are around 20mA (Ive seen as low as 12mA and high as 25mA). As each color change occurs, there is a 5-10mA increase. So a yellow would be 25-30mA, Green would be 35-40, etc. Keep in mind, as I mentioned earlier, the ratings can be off around 7mA (or more).

That said, there will be a tonal difference as well. The Greys will be in simple terms, hotter. So the amp will sound warmer mushier.

For those with simul-class amps. The outside simul sockets (or inside for Coli) will run hotter, so I suggest never going above red or yellow rating or those tubes will wear faster.

This is what I found based on having a shit load of mesa tubes and maxi-matcher tube testers.

 

[Luca79]

Thank you for the answer. We tried the amp, and seem to sound just bit different then before. But the old tubes were already half dead.
So is possible to change color. I guess the tech measured the bias, i think he have something for test the tubes too.

 

[311splawndude]

These are both good reads if you have not already.


https://www.mesaboogie.com/amplitudes/2012/March/mesa-tube-color-codes-by-randall-smith.html
http://forum.grailtone.com/viewtopic.php?t=48652
Not sure what your last comment means? You are saying the Tech measure the bias and you think you have something to test the tubes? The bias is combination of the voltage applied and how the tubes perform (basically) so within the context of amplifiers they kind of go together. But yes, you can change color - just used matched tubes and you'll be fine.

 

[Luca79]

Not sure what your last comment means? You are saying the Tech measure the bias and you think you have something to test the tubes? The bias is combination of the voltage applied and how the tubes perform (basically) so within the context of amplifiers they kind of go together. But yes, you can change color - just used matched tubes and you'll be fine.

Tubes are all Grey and matched. I always though tubes need to be the same color...

Anyway we know the tech have something for test the tubes. We suppose he tested the tubes and measured the bias. I just was skeptical about the color.

 

[311splawndude]

Yeah - you have a better chance of matched tubes within the same color. But if you have a tube tester - that is ideal. It probably has the ability to apply different voltages, so if you know the voltage output of your amp (easy to determine) then you add match pairs off of the tube tester results (really regardless of Mesa's color coding). Using your desired dissipation % (60, 70, whatever) you can find something that works for you. Also, they don't have to be perfectly matched. Most folks would recommend they are within +/- 5mA.

A bit out of my league honestly but that is my understanding. Maybe some of that helps?