Microphonic Reverb tube in a DC-5 ?

[Rubadub]

Loud or effected lines (mostly octave divided midrange)
cause my DC-5 to amplify a rattle;
dialing off the reverb eliminates the rattle,
suggesting a microphonic reverb tube, right?
Can I get a witness in the Amen corner?
I had already wiggled the reverb connections snug,
and checked the easily accessible tubes for looseness;
which tube would be the reverb-controlling culprit?
assuming I'm diagnosing this right,
where do you grailtoners buy your replacement tubes?
This amp has been nearly bulletproof for years...
Hambone Sparklewell

 

[Platypus]

It's not microphonic unless you start hearing squealing or excessive noise.. does it sound like a cabinet full of silverware shaking when you hit a big low chord? It's probably a tube rattling of some sort, do DC's have rectifier tubes? I've solved this problem on combo amps I've owned in the past by replacing the rectifier tube(s).

 

[Rubadub]

Platypus, thanks for the reply;
Microphonic, squealing, rattling silverware, yes, yes, all;
the key was, when I dialed the reverb to zero; the noise stopped;
wouldn't power or rectifier prob affect the sound still, even w/o reverb?
what else could I conclude?;
so, I deduced that the far left tube in the line of preamp tubes
(viewed from the rear of the amp) was the offender,
being closest to the reverb jacks.
Can anyone confirm that this DC5 tube serves the reverb circuit?
B/c when I swapped this tube out with a fresh Mesa GT 12ax7>>>>>
problem solved.
Ah this is lucky, a priori success. A shot in the dark.
Hambone Sparklewell

 

[Platypus]

Ah if there was squealing as well then you were correct and it sounds like you found the culprit. I don't see a tube task chart in the manual for your amp so I cannot comment on if that tube was for reverb for sure.

 

[espexp]

If you are looking for a tube task chart for the DC 5 it is located in the instruction manual for the DC 10 on the Mesa web site. They share the same preamp. I got both manuals just to have that chart.