Please Help Me Trouble Shoot this Problem

[mcbain]

Hi all, my Express 5:50 started making a strange and terrible noise, but only on the clean channel.

It is an intermittent, furry sounding static/crackle that goes away when I change channels, or even to Crunch.

But when I change back quickly, its still there.

It seemed to be more severe in the first hour of my playing time yesterday, then got less frequent.

It occurs regardless of input volume, and gets louder as I turn up.

Does this sound like tubes??
I thought the noise would be global across all channels if it was a tube issue, but Im no expert.

I have 2.5 years left of my 5 year warranty, but I REALLY DONT wanna ship her from FL to Ca if I can help it.

What are some way I can troubleshoot this myself without diving into the amp?

Thanks in advance!

 

[Krek13]

dude don't play it more cus something much worse can happen to your amp...get one 12ax7 and swap one tube at a time and then try the amp, if there is still noise preamp tubes are ok, you can do the same with 6l6s...otherwise use your warranty...

 

[mcbain]

Thank you for the advice.

Can a tube problem just effect a certain channel or toggle mode, like my issue?

Or would a tube issue be across all channels in modes?

Thanks for helping a toob noob.


Im going to call Mesa on Monday regardless.

 

[Krek13]

I don't know, it depends on the construction of the amp...but first suspicion should always be tubes

 

[twally]

Yes,

Start with tubes.
If a tube change doesn't fix the problem, contact Mesa. If you have to send the amp back, they will ask you to remove the chasis and send that versus the whole amp.
That will make shipping less expensive and easier to find shipping boxes.

TW

 

[thunda1216]

most likely the first preamp tube. relax. put a new one in and play.