#1
Hey guys, I have a Fender Blues Junior that I'm pretty sure needs its tubes changed. The amp, after getting a little warm, starts to become almost microphonic. If I tap the amp, I can hear it come through the speaker, and if I play with the tone knob all the way off on the guitar I can hear sputters, squelches and crackles. Does this mean that I need to change the tubes? Or could it be something else? And if it is the tubes, how would I go about replacing them myself? Thanks, and please if this is in the wrong section feel free to move it.

Oh, yeah...I got the amp two years ago and never changed the tubes. I also think it may have been a floor model when it was purchased. This is mainly why I believe that the tubes are the culprit.
Guitars:
Schecter Hellraiser Tempest Left Handed
Yamaha FG720SL Acoustic
Amp(s):
Fender Blues Junior (needs new tubes )
Guitar Rig 4, if that counts
#2
Sounds like a preamp tube. Or you need to replace the tone pot. Its hard to replace preamp tube, just pull out the tube, you may have casing around it, pop in the new one.
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#3
The tubes could be the problem. I was told that tubes should be replaced every two years typically. Also it may be just a connection thing so start with reseeding the tubes there's a release tab and such for the tubes and then pull them out. (might be a slight twist before pulling them) if that doesn't do it then yeah try replacing the tubes as it's about time anyways.
#4
First off, NEVER twist a tube. they aren't ****ing lightbulbs. Pull them straight out, unless you'd like to destroy pins, sockets, and end up replacing more than you thought you would.

If it's microphonic, it could be any tube, but preamps are most often the culprit. Turn the amp up about 2/3, and make sure the volume on your guitar is muted. Now, grab a pencil, and take the eraser and tap the preamp tubes a few times. This should help you find which ones are microphonic. Plus, after heavy use and two years, you may just want to go all out and buy all new tubes, if you have the cash. Power tubes can't have much left in them after 2 years, unless you never play.

Any other questions?
Quote by Invader Jim
The questions people ask here makes me wonder how the TS's dress themselves in the morning and can shower without drowning...
#5
Thank you all for your replies. I took all the tubes out and put them back in, that did the trick. Although, I really should get them changed being I am already overdue for a tube change.
Guitars:
Schecter Hellraiser Tempest Left Handed
Yamaha FG720SL Acoustic
Amp(s):
Fender Blues Junior (needs new tubes )
Guitar Rig 4, if that counts