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
128x128mitch4t
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".
My favorite tube in the 6DJ8 family is the Telefuken E188CC.
It is very detailed and laid-back (if this is the sound you are looking for). Siemens CCAs has more bass, and Valvo E188CCs is detailed but a bit forward. Amperex made many differnt types ranging from 6DJ8,6922,7308 Bugle Boys,PQ,USN,CEP,Gold Pin,World Globe,pinched tubes,made in USA, Hollad A getter& D getters (BTW D getter tubes are mellow sounding tubes)

Anyway, all this is quite maddening. I agree with Wlutke, these tubes can get very expensive, and Ebay is a good source to obtain some of these tubes for a listen. Good Luck!
BTW, here are the US and European equivelent #s for these tubes. 6DJ8-ECC88, 6922-E88CC,CCa, 7308-E188CC, the E288CC european tubes are physically longer in length and have a longer life span. There are also US JAN and British CV military tubes as well.
I am using Gold Aero Platinum, Gold Pin 7308 tubes in my SP9 Mk II. Sounds very much better than Valvo 6DJ8's.
Sorry for tagging on to this thread, but I also would like to know what you would suggest for tube's for my LS 25 mkl and PH 3SE. And....should we keep the pre-amp's and phono amp on (mute) if we listen 1 hour a day???

I welcome your responses!
Rick