The best one is the one that best matches poweramp.
I personally like McCormack preamps. You could use them with high sencitiviy poweramps since they're either passive or have a very low gain. In this situation you get maximum transperency.
I personally like McCormack preamps. You could use them with high sencitiviy poweramps since they're either passive or have a very low gain. In this situation you get maximum transperency.