I just went from a 12ax7 Tungsram ( and many other 12ax7's ) to a Sylvania 5751 3 mica black plate ( Yellow Label ) in my newly Upgraded Thor Audio Linestage and must say its the best 12ax7/5751 I have ever heard ( in my unit ).Sweet,a touch Forward,Dynamic and incredible inner detail.They are not cheap and are hard to find ,but once found well worth the effort and cost...
Replacing 12AX7 to 5751 for pre-amp
Does anyone try NOS Sylvania 5751 replacing 12AX7 for preamp? My friend convinced me trying 5751. I did try them for Dynaco PAS 3 and woo sound is warmer, treble is softer special with vocal. Bass is more tighten than before. I want to try more AU7 or AT7. Do they ok to try? I know that we can replace any 12AX7 with other lower current.