Hi There,
I've completed the initial build of both of my crack kits without having added the speedball upgrades yet. Both kits have passed resistance and voltage checks and both kits are working well. However, one of the 12au7's seems to be a bit microphonic. I can hear it in the phones when I lightly tap the glass. The other kit with its 12au7 does not make noise through the phones when I tap the tube. When I switch the "bad" tube over to the other kit, the issue follows the tube. Is it possible to receive a replacement tube?
Many thanks,
Mark
PS: I've sent this in a reply to my purchase confirmation email too.