i have recently build an a47 amp using this layout http://www.head-fi.org/t/531454/lightbox/post/7173951/id/85920 , and i am now experiencing a hum sound from my headphones when a source signal is not being transmitted, and when a source signal is being transmitted the hum disappears.
the to power the amp im using a 9v battery
the build i in a tin case, both jacks are isolated, and non of the components are getting warm.
could anybody help removing the hum?
Rasmus Suhr Mogensen