Tube equipment these days tend to be very reliable. The non-tube stuff is usually rock solid in high end gear. Tubes are pretty reliable as well, but it never hurts to have an extra set of tubes around. If something happens, then swap tubes.
Preamp cutting out on left side
My Manley Jumbo Shrimp pre amp is cutting in & out on the left side only . Opened up to look for cold solder joint , don't see anything obvious ....poked all the joints with wood stick...seems to cut in & out when I mess with the middle circuit board and the back plate of the box? Any ideas ?