Mosfet amps A true compromise betw. tubes and SS?


I heard from several people that Mosfet SS amps are a nice compromise between tubes and SS amps.
There is one manufacturer in particular I am interested
http://www.wbe-audio.de,s croll down to Fusion 700 (its a German made amp, but he has an English web page) who calls his hybrid amp a Mono tube mosfet amp.
I would really appreciate if someone who has more insight would tell me a bit more of advantages and shortcomings of this design and if the claim: "sound of tubes with power of SS" is true or not. Also I would like to know if these are fast amps, as I plan to maybe use them with my ML Prodigy, should the Wolcott amps, I bought recently, not work satisfactorily.
tekunda
Nelson Pass Amps .Try this link you can get answers directly from Nelson Pass himself and even build your own Pass designed amp .http://www.passdiy.com/amps.htm
Listen to Chaz. Speaking of Pass, I enjoy both tube and Mosfet worlds the economical way. This is how: First get a solid state amp with the least signature. My choice is the Pass X. The guys at Pass Labs told me the X amps are on the lean side (and so they came up with the class A XA). I humbly disagree. The X amp is so transparent to the incoming signal (check the Pass Labs site to see why), that you can taylor the music any way you want with your front end. I use a cd player with a tube power stage. After a bit of tube rolling, I have landed the sweetest (tube) sound with all the black back ground, world class dynamics and bass control of a Mosfet powered amp.
I have to disagree with Muralman1 about Pass X. I think these amps are indeed relatively lean in the midrange compared to some other amps, certainly to certain tube amps or hybrid amps. I'm talking "body" in vocals, "wood" in cellos, "resonance" in piano middle registers, and so on, especially when the reference sound is the real thing. The Pass X series is a very clean and well-made amp, but is leaner than the Aleph. I've noticed its lean midrange character even when using tube preamps and tubed CD players to feed it.
You may be right, Ral, and very soon I will be trying class A mono blocks. I do not agree about the need for tubes in the amp. The Pass X takes what it is fed and simply amplifies while not adding any character of its own.

I am very familiar with the Llano Trinity hybrid, and it mystifies me. No electrical engineer I know believes the Trinity is a class A amp. Not with it's diminutive heat sinks and cool running temperatures. I'm trying to get one over to my place for an audition anyway. A friend of mine is using Telefunken tubes with his. Hearing it at his place, I can't come to any certain conclusion of it's overall worth.

My Apogee Duetta Signature speakers have a rich sound on their own. I've found straight tube amps to be too slow and sticky with the Duetta. The Pass X is the cleanest sounding solid state bar none. It has no character. Coupled with my ribbon speakers and great tubes, the combination is as real as it gets.... With cd material.

I have run straight tubes on slightly brash Apogee Stage speakers, and that had the same synergy in the mids as my Pass plus Duettas. What I want is all the liquid mids of the tubes without the syrup. Mating a tube signal to a sonically passive amp has worked well for me.
Lateral MOSFETs have a negative temperature coefficient and so will basically protect themselves (and your speakers) from over current due to improper sharing or high load demand. They are also faster than BJTs since they aren't minority carrier devices and don't need perfect biasing for good crossover distortion characteristics (if class B). However, MOSFETs are not as linear as BJTs and there is no engineering connection with tubes in term of their sound. Arthur