Help trouble shooting crack

[kagt]

So, I recently jsut finish building my crack everything looks good but there is a weird base sound coming out of the left channel when there is a slight vibration. I have my crack on my computer table but when I type there is a weird base sound. Help would be appreciated thanks.

 

[Paul Birkeland]

This might just be a little bit of tube microphony.  If you tap on either tube with your finger, do you get the same sound?

 

[kagt]

Sounds like it. What should I do to eliminate the problem?

 

[Paul Birkeland]

There's no harm to it.  You can move the Crack away from your keyboard, get a different 12AU7, or put some weight on top of the power transformer.

 

[kagt]

Thanks, I'll try to get a different tube.