JVM 410H problem

Vikings21

New Member
Joined
Jun 20, 2022
Messages
2
Reaction score
0
Hi - I'm having a problem with my 6 month old JVM410H. For the last few weeks it's been making an audible pop when the standby switch is flicked on. Today it did the same and after noticing that the clean volume was pretty weak there was an odd noise and the amp is now making no noise whatsoever. All the tubes are still glowing and the footswitch is still changing channel ok - as seen by the LEDs. It's been fine before this issue - running through a 1960 4 x 10 cab which is not the issue as i've tried it with a different head and it's fine. Any ideas folks??
 

Moony

Well-Known Member
Joined
Jul 3, 2015
Messages
1,335
Reaction score
1,883
The pop when switching on shouldn't appear. The JVM has a 100n cap at the switch to avoid that.
In most cases when new (or at least not that old) tube amps have issues it's the tubes.
So I'd recommend replacing them, if they are bad. You need to find out. Glowing alone doesn't mean the tube is working properly.
 

C-4

Active Member
Joined
May 12, 2011
Messages
75
Reaction score
100
A valve may look fine, but may still not be fine.
Take Moony's advice. :)
 

Pete Farrington

Well-Known Member
Joined
Jan 18, 2021
Messages
1,336
Reaction score
1,440
Location
Staffordshire UK
Yes, valves fail, sometimes they’ll last decades, other minutes. In this case it’s most likely a bad ECC83 / 12AX7.
It’s kinda essential that a valve amp user needs a good spare valve of each type.
It’s excessive to scrap the whole set because one is bad.
Just be methodical and swap the goid valve into each relevant socket in turn and check operation. If no improvement, remove the spare, replace the previous valve, and move on to the next socket.
 

Vikings21

New Member
Joined
Jun 20, 2022
Messages
2
Reaction score
0
Excellent - thanks for the replies and the info. I've previously only used emulator amps so i'm relatively new to the valve amp game - I'll give that a shot!
 

Latest posts



Top