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Any help or assistance would be great,
I just got my JVM 410 back from getting the bias set. When I originally purchased the amp used from CL, there was a mismatched tube, so after while, I decided to pick up a quad of Mullards (EL34) and swapped the tubes. I played the amp for about 10 minutes and it sounded fine. I took it to my local music store to check the amp and set the bias. I asked them to set the bias hot as I had read on the JVM forum (35mA). I got it home yesterday and plugged it in. There now is a very load pop when you take the amp off standby. The amp was definitely HOT, even the clean channel had a more gain. I had to lower all the channel volumes and slowing bring things up to not have the amp squealing. Anyway, I could small the tubes a bit and after about 10 minutes I noticed the tubes getting really hot - very hot. Two of the tubes (the pair on the right if you are standing in front of the amp) where almost fully glowing - not just a few points in the elements I would say a 1 inch diameter of white light on this pair
). Anyway, I shut the amp down immediately and unplugged it. I am obviously pissed at the amp tech and store that did the work, it is hard it believe they would send the amp home like this? I am obviously taking the amp back to them to fix this, but would like to educate myself on what happened? Any ideas.
Thanks for the help
I just got my JVM 410 back from getting the bias set. When I originally purchased the amp used from CL, there was a mismatched tube, so after while, I decided to pick up a quad of Mullards (EL34) and swapped the tubes. I played the amp for about 10 minutes and it sounded fine. I took it to my local music store to check the amp and set the bias. I asked them to set the bias hot as I had read on the JVM forum (35mA). I got it home yesterday and plugged it in. There now is a very load pop when you take the amp off standby. The amp was definitely HOT, even the clean channel had a more gain. I had to lower all the channel volumes and slowing bring things up to not have the amp squealing. Anyway, I could small the tubes a bit and after about 10 minutes I noticed the tubes getting really hot - very hot. Two of the tubes (the pair on the right if you are standing in front of the amp) where almost fully glowing - not just a few points in the elements I would say a 1 inch diameter of white light on this pair
). Anyway, I shut the amp down immediately and unplugged it. I am obviously pissed at the amp tech and store that did the work, it is hard it believe they would send the amp home like this? I am obviously taking the amp back to them to fix this, but would like to educate myself on what happened? Any ideas. Thanks for the help
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