Anyone ever heard this noise? Bad tube maybe?

[jesus_likes_tool]

I put a quad of JJ E34L's in and flipped the bias switch. I turned it on and loved the tone. I was playing with it for a good 20 minutes and I noticed that the tubes were getting REALLY hot. I've never seen my 6L6's get this hot. Even when I put my hand 5 inches above the top vent it felt like an open oven. Also, the tubes were making that "tat, tat" sound like they do when they're heating up or cooling down, but it was non-stop for a few minutes. The "tat, tat, tat, tat, tat, tat, tat, tat..." sound struck me as being strange, but then I started to hear this low "thump" in my signal happening about once per second. (Kind of like if you make a "P" sound with your lips.) I checked cables and turned off the FX loop and it was still there. Even disconnected the guitar.

I changed back to 6L6's and I haven't heard it since. I also noticed that these tubes don't get near that hot. I know this sounds like a weird problem, but has anyone ever seen/heard this before? Is maybe a bad E34L causing the popping sound? Also, do E34L's run hotter or something?

 

[edward]

I had a pair of 6L6s once that started making odd noises, which I would hear only when I stopped playing for a moment. I then left the room for a moment, and just at that moment friends said it went "pop ...poof." I looked inside and saw one dead (and verrrry hot!!) 6L6. I think you've got a bad one.

FWIW, I tried the NOS Seimens EL34s (from Mesa) in my MKIII and love them ...if you're looking to replace your 34s.

Edward

 

[domct203]

Did you look to see if any of the tubes were glowing red?

I had almost the same experience some years ago with an 'Intergrated Sextet' I tried from Eurotubes for a Triple Recto I owned. I was playing the amp, loving the tone, and the fuse popped. When I walked over to the amp it was hot as hell. I replaced the fuse, powered up, and heard some of those noises you described. I hit a chord and watched 2 out of 6 tubes redplate :shock: :shock: . It was one of the E34L's that went red first.

Did you check idle current (bias) when you installed the tubes? Just because you can't adjust the idle current draw (bias), does not mean you can't check it, especially when using non-Mesa tubes. The tubes may have been 'too hot' for the amp.

Dom

 

[jesus_likes_tool]

How do you check the idle current? I didn't notice a red glow, but it might have been hard to tell because the tubes are colored blue. I know other people have used the same make and model tubes in their DR's and never mentioned this.

I've been playing it all day with the 6L6's and there have been no problems. I had it turned on for an hour and it still wasn't near as hot as it was that night. The E34L's sounded better to my ears, so I really want to try them again. If I try them and that popping noise comes back, it will likely prove that its the tubes. Is there any risk in trying them again though? Could a faulty tube have any permanent effects on the amp?

 

[ToneAddictJon]

Most places have at least a 15 day return period on tubes. I'd return them for another set. Are they biased for the roadster?

 

[jesus_likes_tool]

I actually got them from a friend who was using them in his Revision G DR and he didn't report any problems. I was unaware that tubes have to be biased for different amps...? Is there anything else I should know about hastily swapping tubes? I hope I didn't damage my amp if they weren't biased properly.