In my experience ARC ls16,sounds best with the stock sovteks.Tried siemens69229-detail NO bass) & matsushita's 6dj8,(no improvement just noisy)I think ARC preamps are sensitive to nos tubes in general,besides the rip-off factor is too high dealing with these "internet guru's of tubes".
What tubes to use for Audio Research SP-9 MkIII?
I have never opened the case on my AR SP-9 MkIII preamp. I called the guy who sold it to me and he says that it has Sovet6922 or called 6DJ8. A pair of Simens old new stock tubes 6922 made in Germany are for sale for $130 bucks...is the price of the Siemens tubes a good deal? Will the change in tubes make a significant improvement? I've never opened the case...how many tubes will I need? The AR users manual suggests leaving the preamp on all the time....how long will tubes last if the unit is always left on? Thanks,...Mitch