Red plate of death - Rectoverb 25

V30

Member
Messages
12
Hi guys

Seeking some advice.

Bought new matched power tubes (Mesa) for my Rectoverb 25 recently. The amp has been fault free since new (approx 12 - 18 months) and this was the first tube change.

The new tubes have about 2 hours playing time at low to moderate volume.

Was noodling around yesterday at low to mid volume in 10w mode and the right power tube red plated. Noticed a volume drop and crackling, looked at the rear of the amp and the tube was glowing like crazy.

Anyway, switched it off and let it cool down, swapped the power tubes to different sides to see if it was a tube issue, turned it back on and no problems in either 10w or 25w mode.

Any thoughts on what this could be?

I believe the RV25 only uses one power tube in 10w mode. Could it be that particular tube is faulty, hence when I swapped them to the corresponding positions, no red plating?
 

DreamTheaterRules

Former Lyricist for Calhoun Tubbs
Gold Supporting Member
Messages
4,903
The 10 watt mode does not use only one tube, it uses both in Triode. I'd switch to 25 watt mode and keep an eye on them. And of course, it it does anything soon, might be under warranty.
 

Bandersnatch

Member
Messages
740
I believe the RV25 only uses one power tube in 10w mode.

1.A single EL-84 runs 5-7 watts single ended class A

2. If the amp had select-able mode of operation -'SE C/A' like the 5 watt mode in the Mesa TA-15 this would be considered a feature for Mesa to extoll the virtues of and would be made a point of in accompanying literature and official product video demos
 

DreamTheaterRules

Former Lyricist for Calhoun Tubbs
Gold Supporting Member
Messages
4,903
right, they have different options on their different small amps. Owning a V25, Mini Rec, and having owned a TA15 (and maybe owning one again some day) I prefer the TA15 setup. I LOVE the 5 watt Hi1 setting. The bedroom Marshall I always wanted. 5 watts, 1 EL84 SE class A, 15 watts 2 EL84 push pull class A, 25 watts dyna watt (Class A/B) The V25 and Mini Rec have 25 watts Pentode, 10 watts Triode. I like this, and find usable tones with it but rarely use it. Used the 5/15/25 watt switch constantly when I had my TA15.

Anyway, I'd leave them reversed (the tube that red plated in the other EL84 slot) and try it back on full power. I'd watch it closely for a while because if it is a tube, you don't want it taking something else out when it goes. If it's that tube, it will do the same thing in the other slot. If it's a circuit issue, the other tube will do it and you'll know it's not a tube, but the circuit board. If it's OK for a while, I'd bet that the answer above might be correct... was it fully seated when you went in to change it? Back when I had my Tweaker, I thought I had a tube issue right out of the box and was emailing Egnater about it. When I finally opened it up to swap with a known good tube, the tube was not completely seated in the socket. It was all the way down on one side, but not on the other. I pulled it out, shot some Caig on it as I always do, put it back in all the way, and never had another issue.
 

Stormin

Tele's and Plexis
Messages
4,201
Take this for what it's worth - I had one EL34 from a pair in my Shiva red plate one time. I shut the amp down, let it cool and pulled the tube. After an hour I put it back in and never had the problem again.

You may just have had something funky going on within the amp. I'd try it again, but definitely keep an eye on it. If you see it a second time then get rid of that tube.
 

recto-robbie

Member
Messages
2,322
Im willing to bet both dreamtheater and stormin above had the same issue that you are most likely experiencing, most likely the red plated tube wasn't making good contact with one of its pins. Stormin mentioned that he pulled the tube and let it sit then reinstalled and all has been great, it was probably because when he reinstalled the tube all the pins made perfect contact in the socket.
What I like to do when installing tubes is spray the pins with contact cleaner like dreamtheater mentioned and insert the tube, then gently pull it out about half way and finally reinsert it back in again in hopes that all the pins are making a good contact with the metal inside the socket.
 
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V30

Member
Messages
12
Hey guys

Pulled the tubes, used contact cleaner and reinserted. Zero problems so far and I really blew the cobwebs out of it this afternoon.

Thanks for the tips. Appreciated!

Merry Xmas!
 

shanesiegle

Silver Supporting Member
Messages
3,013
Hey guys

Pulled the tubes, used contact cleaner and reinserted. Zero problems so far and I really blew the cobwebs out of it this afternoon.

Thanks for the tips. Appreciated!

Merry Xmas!

Good to hear if it was a bad tube you would have had issues already.
 
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DBK

Member
Messages
2
Tube not properly seated!
Good call. Was just sitting here jamming, having a great time on the fantastic Rectoverb 25 when all of the sudden I got volume drop and fizz. Took a look around back and one of the EL84s was lit up like Rudolph. It was strange to me that soon after I had jostled the amp around to get a look around back that It seemed to cool down. After reading a bit on the ole forums here I took a peak inside the amp and surely enough one side of the offending EL84 was not all the way inserted. If you're reading this forum I'm 99.9% sure you have the same exact issue.
 




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