Unpleasant distortion on certain notes.

[Boxnix]

I have been having an issue with my 5E3 where it has a very nasty sounding distortion but only on or near A, or when playing an A chord. It does not happen when I first turn on the amp but it gets worse as it warms up over the first 15 minutes or so.

What I have done so far:

1.) Replaced all tubes except the rectifier, which is a little low on tread but still working. This has not had any effect that I can tell.

2.) Placed some tissue behind the cone of the speaker. I saw a youtube video that said this should eliminate cone cry if that is the cause. It didn't help.

So now I guess I'm looking at a re-cone or maybe caps? The caps are about five years old maybe. I had the speaker re-coned about the same time. It is a 50W Tone Tubby hemp cone. I did play some bass through it on a looper so I suppose I could have damaged it.

I'm just looking for some advice on where to spend money on it next.

Thanks!

[The Dude]

Checking the speaker is simple enough. Remove it. First inspect it for tears or anything loose- spider, dust cap, etc. Next, applying even pressure, move the cone up and down and see if you here anything rubbing. And/Or, hook the speaker up to another known working amp and see if it does the same thing. You shouldn't need to place tissue behind the cone if the speaker is working correctly. Conversely, you could hook a known good speaker up to the amp and see if the distortion is still there. Until you verify it is not a speaker problem, I wouldn't mess with anything else.

[pdf64]

Are you sure that it's not vibration from the speaker causing an intermittent connection etc in the amp to become apparent, eg does the issue occur if the amp chassis is physically separated from the cab?

[CraigB]

Plus 1 on specific frequency vibration causing intermittent connection. Find it by using a wooden chopstick and pushing every wire and component while the amp is on. Listen for crackling or popping. Cold solder joints, pots with bad traces, cracked teflon wire, and switches with worn contacts are often the culprits.
--Craig

[rjb]

I have been having an issue with my 5E3 where it has a very nasty sounding distortion but only on or near A, or when playing an A chord.

Have you tried tuning down a half step?

-rb