Best Tube Pre-amp to match THRESHOLD 4000 S/S amp

You aleady asked this question and were given two answers regarding this amp and tube preamps.

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1305423724

Riley804, yes you are right about it but still very confused.Other member told me in my other thread to watch out the high output impedance of ARC and other explained to me that tube preamp does not work well w/ 4000.
And another member respond to my e-mail saying he owned 4000 amp and been very impressed w/ the newer ARC LS-17.
" Newer ARC output imp is quite low allowing it to drive Threshold amp ."
Mr.Jon Soderberg told me that any tube pre amp will work well and any older ARC will work well.
That ie why i opened another thread almost identical to the first one.I am trying to be carefull and no mistake.
This is quite hard when you don't understand much but always trying to learn.Thanks a lot anyway.
I thank you all member and I think I should do a lot of reading as well.Thanks anyway.pescolar

Finally after deep research I found the right answer regarding Threshold 4000 input impedance of 75kohm.

Any input added what best pre-amp I should get no more than $2k.

Thanks.pescolar