Leben RS 28CX preamp for Pass Aleph 5?


i'm looking for a new (tube) preamp to be synergistic match to my Pass Aleph 5. So i'm considering  to buy Leben RS 28CX preamp, it has high output gain (that is good attribute for matching Aleph), very good MM phono included and one extra variable output for subwoofer.
I can't  auditioned unit in my home system, so if someone had tried this pre / power combination, i would like to hear your opinions.
My current system: TEAC DV 50, Audio Research LS 16 mkII, Pass Aleph 5, Focal Micro Utopia BE, Magnan interconnect & speaker cables. 
 Any suggestions are welcome.