Tube amp doctor 6L6WGC-STR @ 37-38 mA
How are the TADs working in your OTS?
They were a big improvement compared to the Tungsol's I got from Nik, but then again I don't think those Tungsols were a 100 % ok. I just built my second Ceria overtone for a friend, and this amp was equipped with JJ 6L6, and we did a quick comparison, and we both agreed that the TAD's opened the amp up a little more, and there was a more defined bass response..
Both amps were equipped with NOS ECC83 (mullard tubes), and the V1 and V2 preamp tubes makes a big difference in sound compared to the powertubes... So I would start with the preamp tubes