It was time to replace the power tubes in the JP-2C...

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bandit2013
Triple Recto
Posts: 3143
Joined: Fri Feb 22, 2013 7:31 am
Location: North Carolina

It was time to replace the power tubes in the JP-2C...

Post by bandit2013 » Wed Jun 27, 2018 5:30 am

Ever since I got the JP-2C I was convinced the gray color coded Mesa STR440 tubes were ideal. I have been playing though this amp almost religiously for an hour or more each time. Recently I noticed the amp just did not have the same character as I remembered. It was a gradual change so it was not one of those things that was immediate. I did have a new set of STR440's that are yellow color coded that I bought for the Roadster. I did try those in the TC-100 just to hear how those tubes would sound that amp. Not bad actually. A while back I had a static issue and thought it may be the power tubes since the change in preamp tubes had no effect on that issue. I did have a set of green coded STR440 and was not impressed with that set for what ever reason. Those made it into the Mark V. swapped in the yellows to retire the grays and WOW, the tone of the amp came back as I expected but sounds even better than it did when I got it back in September 2016. Almost 2 years on the first set of power tubes and they still work, tubes were beginning to reveal signs of wear (slight tone change). I probably could have left them in much longer.

I believe Mesa indicated that the Reds have the most headroom, Yellows are next in line, followed by green, gray, blue, white. I tried to get grays again when I bought the quad of tubes but opted for yellow if they had those. If that is more common, I will take them any day. Odd that I did not like the green or gray tubes in the Roadster, never tired the reds in that amp but the yellows have a nice characteristic to them in the Roadster, never expected to have that same trait carried over to the JP-2C. Perhaps I am nuts or have a good ear as I can tell the difference between the color codes, at least in the sets I have from Red, Yellow, Green and Gray. No blues or whites though. Do not fear the yellows if you get them. They are your friend.

bandit2013
Triple Recto
Posts: 3143
Joined: Fri Feb 22, 2013 7:31 am
Location: North Carolina

Re: It was time to replace the power tubes in the JP-2C...

Post by bandit2013 » Sat Jul 14, 2018 9:54 am

I decided to go back to the old STR440 gray color coded tubes. I was feeling the yellows were bringing out the brightness of the amp a bit too much. Sort of love the sinister tone I am getting with the grays more. Could it be due to less headroom? Have not powered it up since I swapped the power tubes back to the originals. Was also thinking of keeping a pair in the yellow in the amp and blend that with a pair of the gray tubes. I have some Reds to try but they have seen better days.

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