Volume Drop when bypass active

[Mark V]

So I was gigging yesterday when suddenly my volume dropped way down.
I had to cranck the master output to 30clock (this is usually way too loud) and even still i could barely hear myself.

After some troubleshooting, it seems that if i bypass the loop, my volume is back line it should be.
Activating the loop again --> serious volume drop.

I changed cables for the loop, but same issue.
There is a gmajor2 in the loop.

Also, I noticed blue flames across all powertubes when activating the loop.

Loop tube gone bad?
Cathode flower tube? (Found a topic on this but it didnt mention the mark v in it)

Anyone that ever had the same issue?

I have the amp a year now. Before i had the combo version for two years without issues.

 

[domct203]

So I was gigging yesterday when suddenly my volume dropped way down.
I had to cranck the master output to 30clock (this is usually way too loud) and even still i could barely hear myself.

After some troubleshooting, it seems that if i bypass the loop, my volume is back line it should be.
Activating the loop again --> serious volume drop.

I changed cables for the loop, but same issue.
There is a gmajor2 in the loop.

Also, I noticed blue flames across all powertubes when activating the loop.

Loop tube gone bad?
Cathode flower tube? (Found a topic on this but it didnt mention the mark v in it)

Anyone that ever had the same issue?

I have the amp a year now. Before i had the combo version for two years without issues.

Try changing your V6 preamp tube. One half of this tube is the FX Return buffer.

99% of "volume drop-outs" are tube related. Always have spare tubes & fuses.

There is no cathode follower use in the MKV preamp.

A blue glow inside the glass of the powertube is normal, and is the result of stray electrons bombarding the glass. In a dark room you should see it form inside the tubes as soon as you switch out of standby. Are you sure it only happens when you activate the loop?

(I love this pic!)

Dom

 

[Mark V]

Thanks, will try that.
Any idea if it needs to be a chinese 12ax7 as mentioned in some topics?

Grts

 

[domct203]

Thanks, will try that.
Any idea if it needs to be a chinese 12ax7 as mentioned in some topics?

Grts

Any quality 12AX7 will be fine.

I'm not sure what topics you are referring to. If you are talking about cathode follower failures that does not apply to the MKV.

Dom

 

[Mark V]

Yes, i was refereing to that.
Thanks for the info!

Grts,
MV