Mesa Triple rec retubing woes

[chaos00013]

I recently re tubed my triple rec(matched sovtek 5881's) and I noticed that on two out of the three channels three of the tubes(the left three at first) we're boiling hot while the others were normal. The tubes came in matched pairs and I installed them in accordance with the, two inner sockets 3, 4 Outer middle sockets 2, 5 Outermost sockets 1, 6 pairing arrangement. So why would channel three be fine but channels two and one had three of them reaching critical mass? I swapped the tubes in a mirror image(1 became 6, 2-5, 3-4) and the same three tubes, now on the opposite side were the hot ones. I can only assume that either the tubes were not paired correctly(this would be fun trying to figure out), the tube were bad(possible), or something is really really wrong with my amp(god I hope not). Any ideas? If it's a matching problem, how can I determine which tubes match if the box was wrong?

 

[123thefirst]

It's not likely at all that something is wrong with your amp. The tubes are likely not properly matched and are out of tolerance to Mesa's specs. That's why Mesa has such a tight system of color coding within a very small range of values compared to other tube distributors.

Also, the 5881's are designed for a lower voltage aren't they? If so then you are taking your chances that they'll survive.

 

[domct203]

Contact the seller and tell them your problem. Most likely the tubes are at fault here.

Do you know how to measure your bias (current draw)?

Dom

 

[chaos00013]

Mesa has a fixed bias, can I still measure it?

 

[domct203]

Mesa has a fixed bias, can I still measure it?

ABSOLUTLY. Mesa uses a non-adjustable fixed bias, so it is even more important to verify that the tubes you install are correct to run in the amp. Different tubes (even of the same type) will have different idle current draw, that is why they are screened and paired by the sellers.

Dom