Upgrading pre amp advice.

I also read very positive comments on the SPL selector.

Someone who has compared this pre amp with the Benchmark LA4?

I guess they are in the same league?

This older review (link) provides some insight on unity gain buffer preamps discussed earlier in this thread. A unity gain buffer does not need to be accomplished using op-amps as the McCormack unit uses FETs.  Basically, an active unity gain circuit allows a high input impedance and low output impedance in order to drive the cables and to provide a low impedance signal to the amplifier thus preserving the tonal qualities and dynamics of the source material.

Over the past 12 years, I have use a McCormack TLC-1 that was upgraded by SMc Audio.  To my ears, and in my system, it sounded better than the (around) 20 pretty good preamps I owned prior to the SMc unit. Those 20 preamps included the Ayre K-5xe, Benchmark LA4, and a bunch of other well-respected units like Lamm's LL2 and more.  I was recently fortunate to upgrade to Steve McCormack's SMc Audio VRE-1C (review links - 1, 2, 3), his statement piece which was designed based on the TLC-1.

+1 Linear Tube Audio 

It has all that magic you're looking for. 

PRE90

Unless your amp has adjustable gain like a Parasound, stay away from the PRE90. I needed a cheap preamp recently and considered the PRE90 since I owned it before but then I remembered how awful to was to pair with amps. It also does even not sound that good with a compatible Parasound amp. I got the $279 Schiit Saga 2 instead which only does RCA.

Another preamp that is surprising decent is the Schiit Kara F. I sold that to raise some cash, but it was rather good. Not as good as the Benchmark LA4. I should have held of selling that.

A preamp that is comparable to the LA4 is the slightly warmer, Holo Audio Serene. I had both the Serene and LA4 in my 2 systems and rotated them round. It is also pretty good like most of the preamps recommended so far.

It lost a bit of luster to me when I took it to a friend's place and is prototype transformer based passive preamp just killed the Serene. I compared them side-by-side. My friend is building a new passive that I am waiting on, thus the purchase of the Schiit Saga 2 to hold me over.

I think a company called Bob's Devices sells something similar to what I am waiting on. As does Townsend Audio in the UK.

@mitch2 : is it comparable to a passive pre amp?

Maybe more people with experiences changing from Bryston BP 2x to another control amp??