I own a TAD-150 and have tried various brands of NOS and used vintage 12AX7, 5751, 12AT7 and 12AU7s from the US & Europe. Right now I am using RCA blackplate 12AU7s. These tubes have excellent bass characteristics and do everything else very well. Another bonus is that the volume knob has much more play in it. 12 o'clock is now very loud insted of 9 o'clock. The 5751s would be my second choice. Good luck in your search.
Time for new tubes.. which ones?
My TAD-150 preamp which has only 2 tubes stays on all the time, so every year I have to replace the tubes. This is my first time replacing them. Does anyone have an opinion as to what tube to use, or should I just use the same replacement ones from TAD? I would like to improve the sound if possible with new tubes. Thanks