Mesa Dual Rec Tube Problem. PLZ help me!

[TheDualRectumFrier]

I have a Dual Rec. Its been working great but it has one problem. Whenever i play it at low volume, it sometimes loses sound and you can hear the tubes getting louder. They HEAT UP AND BURN LIKE CRAZY! they become red and give off so much heat. this is the third time this happened to me. It started about 1 week ago. Only one tube was glowing crazy. But today, 2 were. I dont know why. it looks like I will need to replace all the power tubes with a matched quad of JJ Tesla 6L6's. Can anyone let me know if they know what the problem is?? Thanks

 

[mikey383]

What type of tubes do you have in it now? Are they Mesa tubes? If they are, are you using matched sets in the right postions and inserting them symetrically - e.g. red, blue, blue, red? Are they set to the right bias - e.g. 6L6s on the 6L6 mode, EL34s on the EL34 mode? What are your settings? We need a little more information. This may help in determining a problem.

It sounds as if the tubes are red-plating, meaning the bias is going up so high that it actually turns the plates red. Not a good thing. If you are running Mesa tubes, make sure you are running them in pairs as mentioned before, and if there's still a problem, stop playing and get that amp to a tech immediately. If you aren't running Mesa tubes, you need to get a set that are matched to Mesa specs. Doug's Tubes and Eurotubes both can help you with this.

 

[clutch71]

+1 to what Mikey said. Get those tubes out of there and get a matched quad in there in yesterday. If it's still under warranty go with Mesa tubes.
If your not worried about the warranty just ensure the matched quad is within Mesa's specs. Stock Groove Tubes between 4-7 are acceptable or like Mikey said, contact Doug. Great guy and prices.

The two outside and two inside are matched up. In the mean time you can remove the red plating tube and it's partner. Remove 1 rectifier tube and set the impedance to 4ohm and you should be good to go. It's safe to run the amp in this configuration. If the either of the remaining tuber red plate, get it to a tech ASAP.

Red plating can damage internal circuitry.

 

[mikey383]

The two outside and two inside are matched up. In the mean time you can remove the red plating tube and it's partner. Remove 1 rectifier tube and set the impedance to 4ohm and you should be good to go. It's safe to run the amp in this configuration. If the either of the remaining tuber red plate, get it to a tech ASAP.

Red plating can damage internal circuitry.

Good idea Clutch. I'm going to add to this, just for clarification.

If you do this, plug into the 4 ohm jack only if your cab is 8 ohms. If you have a 16 ohm cab, use the 8 ohm jack. If you have a 4 ohm cab, plug into the 4 ohm jack...even through this is a mismatch, it will be a safe mismatch and shouldn't cause problems.

 

[TheDualRectumFrier]

What type of tubes do you have in it now? Are they Mesa tubes? If they are, are you using matched sets in the right postions and inserting them symetrically - e.g. red, blue, blue, red? Are they set to the right bias - e.g. 6L6s on the 6L6 mode, EL34s on the EL34 mode? What are your settings? We need a little more information. This may help in determining a problem.

It sounds as if the tubes are red-plating, meaning the bias is going up so high that it actually turns the plates red. Not a good thing. If you are running Mesa tubes, make sure you are running them in pairs as mentioned before, and if there's still a problem, stop playing and get that amp to a tech immediately. If you aren't running Mesa tubes, you need to get a set that are matched to Mesa specs. Doug's Tubes and Eurotubes both can help you with this.

Hi. I bought this amp used. The tubes are Mesa and the amp doesnt have warranty. The amp bias is set to 6L6. But i can tell u each power tube from left to right. #1= Mesa STR 440 10 AC GRN #2= STR 430 05 AC RED #3= STR 430 05 AC RED #4=STR 440 10 AC GRN and yesterday both number 3 and number 4 were lighting up like crazy. Before it just number 4. But i played the amp today, and it was fine even though i played it for 10 mins. Love my Mesa to death but I don't know what I should do about this problem. I was thinking to set a quad of matched JJ Tesla 6L6 and change all 4 power tubes out but im not sure if thats going to fix the problem.

 

[BobL]

What type of tubes do you have in it now? Are they Mesa tubes? If they are, are you using matched sets in the right postions and inserting them symetrically - e.g. red, blue, blue, red? Are they set to the right bias - e.g. 6L6s on the 6L6 mode, EL34s on the EL34 mode? What are your settings? We need a little more information. This may help in determining a problem.

It sounds as if the tubes are red-plating, meaning the bias is going up so high that it actually turns the plates red. Not a good thing. If you are running Mesa tubes, make sure you are running them in pairs as mentioned before, and if there's still a problem, stop playing and get that amp to a tech immediately. If you aren't running Mesa tubes, you need to get a set that are matched to Mesa specs. Doug's Tubes and Eurotubes both can help you with this.

Hi. I bought this amp used. The tubes are Mesa and the amp doesnt have warranty. The amp bias is set to 6L6. But i can tell u each power tube from left to right. #1= Mesa STR 440 10 AC GRN #2= STR 430 05 AC RED #3= STR 430 05 AC RED #4=STR 440 10 AC GRN and yesterday both number 3 and number 4 were lighting up like crazy. Before it just number 4. But i played the amp today, and it was fine even though i played it for 10 mins. Love my Mesa to death but I don't know what I should do about this problem. I was thinking to set a quad of matched JJ Tesla 6L6 and change all 4 power tubes out but im not sure if thats going to fix the problem.

The tubes are not matched in your case. Although the good guy's at Mesa will tell you that the rating of the tubes can be different if used and matched inner and outer as stated above, they MUST be the same type tube and be closely matched. Red plating, as it is sometimes called, is the result of a BIAS issue which can be caused by the tube, or a component in the BIAS circuit.

The BIAS holds the tube at idle in a class A/B circuit until a signal is injected. If the BIAS is incorrect then the grid can assume the same voltage as the cathode and can/will result in "red plating", blown fuses, failed rectifier tubes and components. Without a mod Mesa amps are self biasing, however the tubes need to be closely matched for the circuit to work properly. Buy a fully matched set of tubes and the issue should go away. If not the chances are the amp has been damaged and needs repair. Common causes are failed or leaky cathode bypass capacitors or failed or shorted cathode bypass resistors.

Hope this helps.

 

[NoGlassNoClass]

+1 to all above. Get those tubes outta there NOW before you cause any further damage. Go get yourself a matched set (Mesa, Groove Tubes rated 4-7, Doug's Tubes, Eurotubes) and see what happens. If the new tubes still redplate, shut down immediately and get the amp to a tech to have the bias circuit checked out.

 

[TheDualRectumFrier]

wow. I dont really understand about the bias and stuff but I should get those matched JJ 6l6's. I hope it stops the problem. Thanks for everyones comments and BobL you got some AMAZING gear. SO should i just change the power tubes? Do i need to touch the preamp or recto tubes? They didnt give me any problems. But the weird thing is that if i play loud, the red plating doesn't happen. If i play at low volumes for a while, it just suddenly loses volume, and u can hear the tubes buzzing and they just glow and become hot. The recto tubes and power tubes seem excellent because they dont overheat or anything. I can still play it for now as long as i dont play it at low volumes for it not to red plate again? is that ok? Thanks so much for your responses.

 

[TheDualRectumFrier]

Also, i was just browsing thru the site. I came across people who were sharing what bass rigs they have and turmoil posted this pic of his Mesa Triple Rec. How do you get the tubes glowing blue like that? Heres the link:

http://forum.grailtone.com/viewtopic.php?t=5371

Scroll down you’ll see it glowing blue. Someone please let me know how to do that. Thanks

 

[NoGlassNoClass]

Ha ha that's a blue light behind the amp. If your DR starts doing that on it's own, too late for a tech...call a priest.

 

[TheDualRectumFrier]

Ha ha that's a blue light behind the amp. If your DR starts doing that on it's own, too late for a tech...call a priest.

LOL!

 

[clutch71]

With tubes 3 and 4 red plating makes it hard to determine which pair (inner or outer) is the culprit. I'd say get the new tubes and try. Keep the head turned so you can view the back of it and if you see them red plating shut it down so you don't damage the new tubes. If this doesn't correct it, take it to a tech.

At this point (unless you have the money and want a back up set) I think the preamps should be fine. I'd keep an eye on the rectifier tubes as well. If the power tubes red plated in tube rectifier mode they could have been effected. Correct Bobl Mikey?

Hopefully this isn't why the person sold the amp.

Good luck.

 

[mikey383]

Yeah, keep an eye on the rectifiers too if you were using them. They may go prematurely, due to the extra current being pulled through them.

+1 to getting a matched set. If you want, you could just pull a pair and run it in 50 watt mode, and if it does the same thing - swap them out with the other set.

 

[Mystic-Creations]

Ha ha that's a blue light behind the amp. If your DR starts doing that on it's own, too late for a tech...call a priest.

:lol: thanks for the lol

 

[BobL]

With tubes 3 and 4 red plating makes it hard to determine which pair (inner or outer) is the culprit. I'd say get the new tubes and try. Keep the head turned so you can view the back of it and if you see them red plating shut it down so you don't damage the new tubes. If this doesn't correct it, take it to a tech.

At this point (unless you have the money and want a back up set) I think the preamps should be fine. I'd keep an eye on the rectifier tubes as well. If the power tubes red plated in tube rectifier mode they could have been effected. Correct Bobl Mikey?

Hopefully this isn't why the person sold the amp.

Good luck.

Correct.

 

[TheDualRectumFrier]

Hey guys. My amp tech (family friend) came to my house and checked it out and nothing happened to the circuitry. Nothing was wrong with the amp. he tested each tube and said that 2 of them have really different voltages and 2 tubes weren't a matched pair. so i got those pulled out. and im running the pair of tubes which is matched. sounds killer and i can crank it higher and no more red plating. So he was at my house for 2 hours checking put the amp and testing it with a multimeter and paid him only 20 bucks. SO ill but a nice matched pair of tubes. JJ's for sure. thanks so much guys for the advice.

 

[BobL]

Hey guys. My amp tech (family friend) came to my house and checked it out and nothing happened to the circuitry. Nothing was wrong with the amp. he tested each tube and said that 2 of them have really different voltages and 2 tubes weren't a matched pair. so i got those pulled out. and im running the pair of tubes which is matched. sounds killer and i can crank it higher and no more red plating. So he was at my house for 2 hours checking put the amp and testing it with a multimeter and paid him only 20 bucks. SO ill but a nice matched pair of tubes. JJ's for sure. thanks so much guys for the advice.

Hey Dual,
I'm glad to hear you've solvedthe problem. I suggest that you don't eliminate the GT 6L6 GE's from consideration. They're a little pricey but worth the money.

 

[TheDualRectumFrier]

Hey guys. My amp tech (family friend) came to my house and checked it out and nothing happened to the circuitry. Nothing was wrong with the amp. he tested each tube and said that 2 of them have really different voltages and 2 tubes weren't a matched pair. so i got those pulled out. and im running the pair of tubes which is matched. sounds killer and i can crank it higher and no more red plating. So he was at my house for 2 hours checking put the amp and testing it with a multimeter and paid him only 20 bucks. SO ill but a nice matched pair of tubes. JJ's for sure. thanks so much guys for the advice.

Hey Dual,
I'm glad to hear you've solvedthe problem. I suggest that you don't eliminate the GT 6L6 GE's from consideration. They're a little pricey but worth the money.

Hey. I got a matched quad of JJ Tesla 6L6 for 55 dollars. THEY SOUND SOOOOOOOOOO MUCH better than the stock Mesa tubes. Clean channel sounds more like a fender clean and distortion is much tighter with more definition. Wow, I friggin love my mesa. Although, i still a question about that light that another person used in their mesa. I attached the link in the previous threads. Would anyone have any suggestions on how i can do that? Many Thanks.