Mesa color codes

[anomaly]

So I got a Mark IV and i've got green color code 6l6's and a pair of yellow 6l6's, which go where for the best tone and operation. I was told to put the yellows on the outside pair and green on the inside pair, is this right? It's a simulclass amp obviously.

 

[anomaly]

I just put all green color code 6l6's in the amp, had a couple old ones that are still good lying around. They're a matched pair but one is glowing a little brighter than the other, is that anything to worry about??

 

[stephen sawall]

I don't think so. Most of my amps do that. Watch it for red plating. Unlikely but better to catch it.

 

[psychodave]

If I remember correctly, it goes from coldest to hottest: red, yellow, green, blue… I can’t remember gray and white. So for simul sockets, you want red or yellow when running 6L6’s in place of EL34’s since they will run hotter. Of course this is subjective because green and blue will work fine as well and may sound better to you…but they will burn out faster.

Running all red, yellow or green is fine. Keep in mind that when I tested multiple sets of each color, there was only a 5-7mA difference between each color. So if red ran at 25mA, yellow would be around 30-32, green 35-37, etc. of course with tubes they will fluctuate.

 

[Frehley12]

I have a Mark IV. I thought simul-class meant a pair of 6L6s and a pair of EL-34s. I don't think the quad of 6L6s being different colors is going to actually matter.

I've tried a pair of 6L6s and a pair of EL-34s. I prefer all 6L6s. Those just have more sparkle in the cleans and less "stiff" in the crunch and lead channels. It was tighter in the bass though with mixing the tubes. IMO.

 

[GJgo]

For 6L6 in a Mark IV-

Outer Class A Pair- GRN is about as hot as you'd want to go, high 30s. GRY is getting high 40s which is pushing it. Note that this is NOT the case in Mark IIs and IIIs where RED, maybe YEL is as hot as you want to go. The Class A pair in the IVs is in comparison super cold.

Inner Class A/B Pair - GRY is about as hot as you want to go, high 30s. GRN will be low 30s. YEL mid 20s. Give or take.

 

[anomaly]

For 6L6 in a Mark IV-

Outer Class A Pair- GRN is about as hot as you'd want to go, high 30s. GRY is getting high 40s which is pushing it. Note that this is NOT the case in Mark IIs and IIIs where RED, maybe YEL is as hot as you want to go. The Class A pair in the IVs is in comparison super cold.

Inner Class A/B Pair - GRY is about as hot as you want to go, high 30s. GRN will be low 30s. YEL mid 20s. Give or take.

Thanks for the reply GJgo, very helpful. I might wanna swap out those greens on the outer two tubes then?? What color do you suggest? Or should I just keep them in if they're sounding and working fine??

 

[anomaly]

I have a Mark IV. I thought simul-class meant a pair of 6L6s and a pair of EL-34s. I don't think the quad of 6L6s being different colors is going to actually matter.

I've tried a pair of 6L6s and a pair of EL-34s. I prefer all 6L6s. Those just have more sparkle in the cleans and less "stiff" in the crunch and lead channels. It was tighter in the bass though with mixing the tubes. IMO.

It's simulclass regardless of the tubes. It just refers to the inner two slots being class AB and the outer pairs being class A. Not technically class A, but that is the idea of it.

 

[GJgo]

Thanks for the reply GJgo, very helpful. I might wanna swap out those greens on the outer two tubes then?? What color do you suggest? Or should I just keep them in if they're sounding and working fine??

I'd just run the YEL in the outer pair & GRN in the inner pair & rock on.

 

[anomaly]

I'd just run the YEL in the outer pair & GRN in the inner pair & rock on.

One problem, those Yellow 6l6's, one of them might be blown?? Can I try it out in tweed mode first to see if one is blown without hurting my amp?

 

[GJgo]

If in doubt I'd replace them. A bad tube can just blow a fuse, or it can cook a screen resistor.