Have run my D115 MkIIs with both the SP10 MkII and Sp11 (with a Siemens tube upgrade on the phono side and telefunken on the line). The tube upgrade on the 11 was a noticable improvement. The line stage of the 11 is much better than the 10 IMHO. The phono side of the 11 was also more detailed; I noticed this difference between the 11 and 10 right away.
But if you play LPs, the 10 is the pre for you. Yes, the tubes are expensive (I've gone the amperex route with my 10, but have not noticed nearly the improvement that the siemens upgrade brought to the 11), but the difference in the music between the 10 and 11 was immediately heard. The 10 just sounds better, to me -- way better. I still have the 11 and use it for CDs upstairs, but in my listening room (filled with LPs) is the 10.
BTW you may have already made your decision, if you have, how did you go?
But if you play LPs, the 10 is the pre for you. Yes, the tubes are expensive (I've gone the amperex route with my 10, but have not noticed nearly the improvement that the siemens upgrade brought to the 11), but the difference in the music between the 10 and 11 was immediately heard. The 10 just sounds better, to me -- way better. I still have the 11 and use it for CDs upstairs, but in my listening room (filled with LPs) is the 10.
BTW you may have already made your decision, if you have, how did you go?