So I found out one reason why my 2525H was lacking balls was that it was running on one power tube. Looking for recommendations on what power tube would fill in the bottom end the best. Currently running JJ E34L's. I'm looking at: Marshall branded TungSol EL34B's - same that came with the amp. ~ $60 Gold Lion KT77 - sort of pricey. ~ $100 A Used pair Mullard XF2 for the same price as the Gold Lions that are new. Others? For the knowledge of the forum, my E34L's in 20 watt mode have 250 volts on the plates and around 55ma of current. In low power mode the plate voltage dropped in half, and I can't remember what the bias was but is was lower, in the 30's I think. The LED's on the circuit board are tiny compared to the old ones.