Hi everyone,
Thank you for you guys responds. After I posted the question, I have tried four different preamp. First, I tried the ARC LS-25 MK I, but I did not like it because sound was not forward, may be it was not my type. Second, I tried the Simaudio moon P-3, I like this better than the ARC, sound was more dynamic. Third, because I like the P-3, then I had good opportunity to buy a Simaudio P-5 LE with fairly low price from a local audiogoner. I love it, it brings my 250.5 to another level. But few weeks ago, one of my audiophile friends bring his X-1 to my house and I like the X-1 better. I don't know the X-1 can really beat the P-5 LE, but they definitely have better match. So I finally bought a X-1 two weeks ago and plan to buy a Xono later. make all Pass stuffs.
Thank you for you guys responds.