I have the same amp and love it, it’s been the best tube amp I’ve ever used. With 60 watts per side it puts out a ton of heat. Watch out where you install it at. It needs a ton of room to breathe and keep the heat down as much as possible. This amp love to have the tubes rolled but not many options for the KT120 tubes
Got one in 2011 . Also have a pair of early 60's st 70's. Excellent value. Advice : Keep the sockets clean . Any issues i have had were due to dirty ones . also I am running the KT 88 @ .45 v and i run the kt -120 @ .5 v (with a webber copper cap ).very dependable when you just understand new tubes are simply not as hardy as the old . I have an EICO ST 40 integrated amp using original tubes . Mullard made for eico .