Troubleshooting a Dual Rectifier (most likely tube problems)

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DeadCell
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Joined: Mon Jun 18, 2012 1:03 pm

Troubleshooting a Dual Rectifier (most likely tube problems)

Post by DeadCell »

Here's what happened:
Saturday night I was playing and started noticing some popping noises, even when my guitar cable was unplugged. I also noticed some very light flickering in the 2nd power tube, and it had a blue hue to it.

I ordered some 6l6GC's to install tomorrow, as well as some Deoxit for the pins/sockets.

Well, I decided to do some more testing last night and was going to tap each tube with a drum stick and see if I could reproduce the popping. Nothing, no popping. Good. So I hooked up my guitar and I almost have to crank the amp to even hear anything. The red channel wasn't audible at all until I switched to the orange channel and back. All channels have very low volume and the sound breaks up very easily.

I thought the rectifier tubes may be the problem, but I swapped over to diodes with no change in output. So that rules out the recto tubes.

The manual says that these sort of problems could be caused by power tubes, or maybe even the driver tube. However, I've read elsewhere on the internet that it could be the preamp tubes.

Any ideas?

Andy92
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Re: Troubleshooting a Dual Rectifier (most likely tube probl

Post by Andy92 »

A pop followed by a volume drop is almost always a power tube issue. Go ahead and replace all the power tubes at the same time. The preamp tubes can be replaced individually, but it's best to replace all power tubes together.

See if that fixes it up, and if not we'll try to figure it out from there.
anguyen92 wrote:Oh well. Deal with it.

DeadCell
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Joined: Mon Jun 18, 2012 1:03 pm

Re: Troubleshooting a Dual Rectifier (most likely tube probl

Post by DeadCell »

Thanks Andy, I appreciate the advice. Power tubes should be here tomorrow so I'll give it a shot.

I also have three 12AX7's on the way as well. They should be here early next week. If the power tubes fix it then awesome.... I guess I'll have some spare preamp tubes.

Andy92
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Joined: Sun Jun 17, 2012 11:52 pm

Re: Troubleshooting a Dual Rectifier (most likely tube probl

Post by Andy92 »

It's always nice to have spares just in case. If swapping power tubes doesn't fix it, just change the preamp tubes one by one. Just swap the first one, try it, and if it still doesn't work put the old one back in and swap out the second one. Just continue until you find the bad one. I'd bet it's power tubes though. Tubes will be dimly lit when they're on, but the blue hue and flickering one sounds like it was your issue.
anguyen92 wrote:Oh well. Deal with it.

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