Summary:
This is a pretty simple review. Why? I have had this thing over a year and I cannot tell you what it sounds like.

It appears to be that neutral.

True, Adcom (a Pass design) may be a better value, but it is dark, less energetic, and screws up the vocals in comparison to the Pass X0.

Strengths:
Neutrality

Weaknesses:
Slight, but brief noise heard when crossing the x10db barrier (10,20,30,40,...).

Couldn't get mono mode to work with my X350. However, it seems to work with my Lamm 1.1 amplifiers.

Also, the remote turn on did not come with it as documented.

Similar Products Used:
Classe CP60
Adcom GFP-750
Carver LightStar
Parasound

Summary:
I've heard the Jeff Rowland models and the Krells. Sonically, this is in the same league. Like the Jeff Rowland models, it has two sets of balanced (XLR) outputs. I got a very good deal on a 3-month-old unit in mint condition, which made it a bargain. The remote is heavy and slightly over-sized, although it works from far away and at odd angles. My German friends equate this heft with 'quality,' but what can you expect from people who build BMWs? On the whole, it's built like a BMW: precisely-milled, heavy, thick metal that is more-than-securely bolted together. It will probably survive the apocalypse. Maybe the meek will use mine when they inherit the earth.

Strengths:
Very clear sound throughout spectrum; especially high end: does not sound like it came from a tin can.

Weaknesses:
I have one of the original units. Some of the control features do not work, (e.g., A function that allows the two channels to have different volumes) but none that interfere with the sound.

Similar Products Used:
None with the same configuration of speakers, amplifiers & cables. Currently: Sonus Faber Extremas, Dynaudio Confidence 3s, DH Labs Q-10 & air matrix cables, Krell Amplifier

Summary:
This is one of the finest pre-amps that I have heard. It is totally without any sonic signature. Pure,simple & elegant.
Exactly what a reference pre-amp should be.
The only caveat is that it requires 400-500 hours to burn in.

Current System:

Advantage T-1 Transport.
Krell Reference 64 DAC.
Pass XO Pre-amp.
Krell KAS2 Power-amps.
EW Andra's.
Quattro Fil (XLR) interconnects
Yamamura Churchill M6000 Speaker cable.

Strengths:
Utterly transparent. Superb build quality.

Weaknesses:
None except Remote Control could be improved upon.

Similar Products Used:
Krell KRC, Krell KRC-HR,BAT-50SE & others.