McIntosh C100, Ayre K1 or Mark Levinson 380/380S?

Obviously, the best thing to do is to demo them yourself, however, I will discuss what I know of two of the ones you mentioned.

I have the Ayre K-1XE preamp, and it is the cornerstone of my system. (I doubt I will be upgrading beyond it to be honest.)

This preamp is very neutral, has great transparency, and has good frequency extension. It has a very musical sound, that I normally would not associate with solid state. It is not warm per se, but it really does not sound solid state either, IMHO anyway. (Note: I would not consider this to be a warm sounding preamp however. If you desire that, I suggest a tube preamp, like a ARC Ref. series, a Hovland, or a CAT Ultimate.) It has 6 inputs, 3 SE and 3 XLR. It is a fully balanced design. I like having so many inputs, as I use a CD, CD-R, SACD, Turntable and a tuner. (Damn, I need one more balanced component to fill 'er up!!) The build quality is excellent. (And while it does not matter to the sound quality, I like the aesthetics of the unit too.)

It has the (optional) remote control. (Note: not all of the top end preamps have a remote option, and I really like having a remote, since I use a analog source mostly), although it does only control the volume and muting).

It also has (optional) phono boards that are very good. This makes the phono stage about as good as you can get in a full function preamp. It has the deep dark background that I really like. You can get a better phono stage, if you are willing to spend big time cash for something like a Manley Steelhead or a Basis ASR Exclusive. (I will point out that the phono stage uses the XLR inputs, like the Basis ASR does. So you will likely either need to use adapters or have your tonearm wire reterminated.)

I did demo the Mark Levinson 380S, and it was good preamp, but I prefer my Ayre, as it seemed, to me at least, a little less solid state sounding. It seemed a little analytical to me. (However, if you already have a warm sounding system, this might not be a concern.) I was running an all solid state system at the time, and I did not want too much of the solid state sound. The build quality is top notch.

I know nothing about the McIntosh.

Hope this helps.

Good Luck in your search.

My suggestion is to narrow down what you really want in a preamp, and what you don't need. This will help you decide which preamp is right for you

For instance, which of these features do you really want:

A. Remote Control (This is a must for some people, like me, but to others, they feel it can affect the sonics of the unit. Certain manufacuturers deal with the sonic impact in different ways.)

B. Phono Stage (If you don't run an analog source, or if you already have a separate phono preamp, you don't need it. But if you planning on getting one in the future, it is nice to have it available.)

C. Balanced or Single ended inputs and outputs

D. Number of inputs (Just a few or lots of inputs)

E. Tube or Solid State (i.e. Do you wish to make the music warmer, or get more detail, or a combination of the two? Do you like tube rolling, or hate tube rushing? There are many factors in choosing between the two.)

F. Aesthetics (This is not so much a feature, as it is a question of whether the unit will "fit" with the rest of your system. This not a necessary requirement obviously, but it just might tip the scales between two units that have both met all your requirements otherwise.)

My two cents worth.