Sorry I confused you I said in the last post I will probably just leave it for what it is in other words not hotrod the 5e3 as I have my 5f4 build though that too is a bit different as it has a massive OT from a Peavey Amp that used 4 6l6s meaning I have that 5f4 for more power along with the bogen pa head project, though the 5f4 is a bit different too with that large OT. I guess I should not have talked about 3 amps in the same post to confuse the issue. Sorry. NOW back to the 5e3 The OT for the 5e3 build is the stock Zenith OT that was on the chassis. I used both the PT and OT that were on the chassis since the origional zenith had all the same tubes except for a octal preamp tube a little less powerfull than a 12ax7 I think it ws a 6J5 if I remember right or something like that I swapped out that octal socket for a 9 pin socket to use the 12ay7.12ax7 the 5e3 calls for. Tubes are all OK they have all be checked and double checked. what could be the issue with the Input circuit??? that you may suspect???