I have compared the Quicksilver, CJ 10 & 14, Rogue M-99?, AL 3A and Counterpoint SA-5 preamps. The Countepoint had NOS tubes while the othes had stock tubes. The overall favorite was the Counterpoint with the 3A close behind. The other two preamps that impressed us were the Placette remote volume and the Sonic Euphoria passive units. You will need to make sure the passives work with your amp. What I like about the Counterpoint is that there is an upgrade path, not sure if anyone modifies the others.
Happy Listening.
Happy Listening.