ringing when amp is on

[sevycat]

When I have my mark v powered on there is a faint ringing sound, does not happen when the amp is in standby mode. I am wondering if this is a preamp or power tube issue. Any help would steer me in the right direction to trouble shoot this issue. Thanks!

 

[Neptical]

When I have my mark v powered on there is a faint ringing sound, does not happen when the amp is in standby mode. I am wondering if this is a preamp or power tube issue. Any help would steer me in the right direction to trouble shoot this issue. Thanks!

Microphonic preamp tube. Give each preamp tube the ole 'tap test' with a pen or pencil to determine which tube is causing the issue. Good luck!

~Nep~

 

[eudaimonia02912]

Yep, that's a microphonic preamp tube.

 

[sevycat]

I turned the volume all the way down on the guitar and turned up the gain on the amp and the ringing or feedback gets louder, do you all still think this is a microphonic preamp tube. I was sitting approx 3 feet away from the amp and the amp is raised off the floor when I tested it again.

 

[>Photi G<]

Yes, microphonic preamp tubes make noise even if the guitar volume is rolled off, or completely unplugged. Give it the tap test.