I've been messing around with my Fender amp's preamp section lately. I thought I was set on the tubes I had until I started looking at NOS ones. So I got myself a pair of Telefunken 12AX7s and now I'm not sure where to put them! My amp has 5 preamp tube slots, one of which is of course the reverb one that is covered by my Mullard 12AT7, so I wanna hear what you guys think of which should head where. 2 x Telefunken 2 x Tungsram 4 x SED Winged C The above are my current stash of 12AX7s. Also, would changing my power tubes from the SED Winged C 6L6GC to the NOS RCA Black Plate really make much of a difference, if any, in terms of tone? Would appreciate some advice here! Thanks.