Earthquake 200dhc with hum in output

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Here is the best pic I could get using the ground terminal as a reference. Should I always use the ground terminal when working on an amplifier? Or does it depend on the circuit you are working on?
scope2.jpg
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.