TOV very loud intermittent shorting sound when amp warms up

[mixtery]

Later model TOV combo loaded with JJ34L etc.
this happened at a show in the middle of the set an extremely loud
Buzz or hum overcame the guitar sound and I had to
Go to bypass and power off. After the gig tried the amp again
And it was normal again. Then the sound came back and the only
Way to stop is to shut down. I've confirmed it's not the guitar
Or my cables and pedals.

Does this sound like a intermittent bad tube or short
Somewhere when things are starting to heat up?

Edit: when I play the amp at Low volumes it
Doesn't seem to happen as much


Thanks!

 

[Authorized Boogie]

Later model TOV combo loaded with JJ34L etc.
this happened at a show in the middle of the set an extremely loud
Buzz or hum overcame the guitar sound and I had to
Go to bypass and power off. After the gig tried the amp again
And it was normal again. Then the sound came back and the only
Way to stop is to shut down. I've confirmed it's not the guitar
Or my cables and pedals.

Does this sound like a intermittent bad tube or short
Somewhere when things are starting to heat up?

Edit: when I play the amp at Low volumes it
Doesn't seem to happen as much


Thanks!

It sounds like a power tube that is shorting and WILL fail. By turning the amp to standby/off the electrons settle down, and the short subsides. Don't risk doing any damage, and get your power tubes checked out!

 

[mixtery]

Ok will replace and report back

 

[mixtery]

Ok got some new JJ el34's in. Now using
The two outer slots to still run in half power.
Still the same issue. After 10 mins I start to hear
These short bursts of a shorting sound. They seem
To actually get louder and more severe but random in
Occurrence. Could it be from The combo's vibration?
Or from things warming up?

Advice please....

 

[bendo]

Have you also removed one Rectifier tube so that you are only running one Rectifier?

Have you tried switching to Diode Rectification? Does the issue persist there?

Also, did you replace all 6 pre-amp tubes?

I have seen in the past where a tone capacitor has worked/vibrated/broken itself free from it's solder. It will sound just like what you are describing. I had it happen on my DC3. Would only happen at loud volumes (more vibration). Turned out to be the .1 and .047 caps just off of V1B. Re-flowed the solder to those caps, added some silicone, and the issue was resolved.

If you are not comfortable working inside of an amplifier, I would recommend taking it to a tech.

 

[Leroy Crow]

Doubt it has anything to do with your problem but worth mentioning, along with removing one of the rectifier tubes I was told to make sure to compensate for the load on the amp by running out the 4 ohm output (when running the TOVs normal 8 ohm load). I'm guessing that if you didn't due this you could possibly burn something up but from what I understand it would more likely be a Output transformer and not tubes....

 

[mixtery]

I have tried it in both silicon and tube modes and the problem
Persists. When I run half power by pulling two
EL34s I use the 8 ohm speaker jack.
I have removed the amp chassis from the
Combo cabinet to see if decreased vibration
Has an effect.
I have not replaced v1 yet. Problem has occurred
On both channels.


Will report back. I've had the amp
Go down on me twice at gigs. First time was blown power
Tube and speaker from poor club power and then
This issue. I've had the amp worked on by my
mesa endorsed tech as well. Thinking of sending
The amp to Mesa to recap and test.

 

[mixtery]

I was thinking of getting a simpler gigging amp
Since I only use the orange channel of TOV live.
I use pedals for gain. What other Mesa does a good
Replication of the orange channel in sound?
Note, amp must be reliable!

 

[cyber104]

Mesa is the most reliable you can buy. Their build quality is superior. Get your amp to a competent tech or send it to Mesa