Hey guys - I posted this on another forum but thought there is so much knowledge here I would try my luck twice!
Just recently received my second (let the first one foolishly go) YJM head and am loving it - BUT, there is definitely something up with my Boost. Even with the NG not engaged I will be playing at volume and all of a sudden my volume will drop in half for a little while and then come back to full volume again.
it is almost like maybe there is an incomplete connection or join somewhere - I dont suppose there is any chance that a particular preamp tube position is responsible solely for the Boost? I dont know if it's a tube though because the amp seems to work perfectly fine when the Boost is not engaged...but in some ways I was hoping maybe it could be as easy as a preamp tube swap or something.
incidentally, i did run the autobias for the correct range when i first received the amp - i thought i was through the woods since there was no problem with the procedure, which i know others have suffered from...but i guess i was happy too soon!