Mark III Combo Problem

[anthonym12]

This seems to be the place to ask questions and be answered on all things Mesa Boogie so here goes!
Well.. I don't think it's a pre-1991 Mesa (S/N 27116).. but the Mark III line is.. so I thought I'd post in here anyway.
It's a Blue Stripe non-simul class combo (2 x 6L6) with GEQ & Reverb, though for some reason I doubt this has anything to do with my problem.
I acquired this amplifier a few months ago and have had unbounded pleasure with it.. I've only played guitar for a few years and was using a Marshall DSL50 before deciding I wanted something different and haven't looked back!
Back to the problem: One day, as no doubt many of you do, I was sitting back, playing some bluesy stuff on the R1 channel and noticed a soft crackling sound coming from the speaker... it didn't seem to be restricted to any frequencies but was definitely louder on the D/G strings... the problem seems to come and go depending on what day it is and for how long i have it plugged in, the problem is more distracting than anything and is only discernible on the R1 channel.
My presumption is that either the filter capacitors need to be replaced, the speaker has damage, or the electronics in my guitar need replacing... I'm not really able to check my guitar as I only have one guitar.
Any input or thoughts on the matter would be greatly appreciated!
I do get the feeling this wont be a cheap fix though.
Thanks guys!

 

[Tuna141]

It's probably just a tube going bad. I'd try changing your preamp tubes one at a time to see if the problem goes away.

If that doesn't work try the power tubes.

Good luck.

 

[anthonym12]

Thanks for the speedy reply man!
I'll give it a go as soon as i can, cheers!

 

[SonicProvocateur]

Yep, definitely sounds like a preamp tube. Always good to have good spares around with the Mark III.

 

[anthonym12]

Have I done something really bad?
I've ordered a new set of JJ ECC83S's which seem to be what everyone says to use, however, I've been keeping on playing it anyway, and a few hours ago I stopped playing and turned it on to standby, and while i was standing next to it I could hear a slow, rythmic clicking sound... I get the feeling that probably shouldn't be there.

 

[MrMarkIII]

Could it be the fan?

 

[anthonym12]

No fan that I can see in the back of this combo.

 

[Tuna141]

Most likely one of the tubes just went completely bad.

You can power it on while looking at the tubes to see if you observe any bright flashes or other anomalies. You may be able to spot which tube went bad.

I suggest you power it down quickly after the power-up test, so you don't do any more damage, and wait for your new tubes to arrive.

If it's not the tubes, I suggest taking it to a Mesa Tech.