Upgrading pre amp advice.

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??

@vhond - The idea was to preserve the natural sound of a passive while maintaining the dynamics and tonal color of an active stage. My upgraded TLC-1 provided unity gain, so it was an active buffer and it sounded way better than any of the passives I have owned/tried including, Goldpoint, Endler, and Hattor.

If I had to have a passive, I would look at an AVC type, which preserves suitable impedance matching so you don’t lose the bass punch and dynamics as you do with resistor passives.  I have owned several AVC preamps including icon Pro4, Acoustic Imagery JaySho and, most recently, Hattor’s ARP (link), which is what I would recommend to those who want an AVC preamp at a reasonable price.

Another (IMO) very good sounding preamp for the money is Hattor’s The Big Preamp (link) with AMRG resistors. It offers passive or active modes, with switchable gain levels of 3/6/9 dB.