What is the best phono preamp you have heard?

Interesting the mention of the Herron. Cmk, have you ever heard it in conjunction with the VTSP-1A linestage? Having already bought a K&K phono stage (which I think is as good as most anything up to the Io non-signature) I decided not to get a VTPH-1mc when I bought the VTSP-1A, but understand it is a fine piece.

I have pined for a Io Sig. Mebbe some day.

Pass Labs XONO, Rowland

Pass Aleph Ono -- very good. Manley Steelhead -- awesome.

4yanx, not yet.
So far everyone who has heard the Herron readily agrees its a great piece of engineering. Its a good match for the Dynavectors 0.25mv output. I don't quite understand how it works exactly, but it works fine at 47k ohms for low output mcs, sounding extraordinarily detailed and dynamic, not bright at all. In fact I've tried it with the Urushi, Allaerts and the owners said their carts never sounded better.

WHAT make a pre-amp the (Best),what does it do that other will not do.Also in what type of system do this apply in, or is it every type of system.
Thank You