Anyone own one of these preamps ?

I had the Herron for a while.  Impressive dynamics and big bass.  Inner detail buried (noise floor).  No audible hum or rush.  A nice sounding pre for the music lover.  Quick, colored and colorful.

@wlutke  thanks.    I myself have a Herron phono preamp that I’m a big fan of, but have never listened to the line preamp.  

I use the Benchmark LA4.  It is totally transparent, if your system is at all bright this is not good, but if you are looking for resolution, spatial awareness and neutrality you cannot do better.  If you want "soul" look elsewhere.

It has two RCA and two balanced XLR inputs, single RCA and XLTR out, plus a mono XLR.

Volume is controlled by relays and precision resistors.  The remote will control volume and input selection.

The reviews of this component are accurate.

A thought, in your price range, is the Cary SLP-98.

these are units that more or less intrigued him in one way or another over the past 5 or 10 years but as I said in the original post, he’ll need to determine synergies (or lack of) with the rest of his system.  

It still all comes down to what sound characteristics are most important to him and what specific improvements he’s looking for over what he has now, so again I ask what preamp is he using now and what specific improvements he’s looking for?  Frankly if he’s considering all those preamps it indicates to me he doesn’t know what he’s looking for because they’re mostly not substitutes at all as they’re so completely different. 

I don’t disagree with you, it’s like a mish-mosh of different kinds of sounds.    He can get his own Agon account lmaooo.    But his amp (Parasound A21+) is pretty solid IMO.   The Parasound P5 preamp is a weak spot, again IMO.