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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
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swampwalker
5,132 posts
 

Think I will jump in with a thought on the Llano Trinity. I'm using mine with a BAT VK3i amp and Vandy 3ASigs. I have tried various tubes in the 12A?7 series and typically found the 12AT7s and AX7s to be a little forward in the upper vocal registers. Since I listen to a lot of female vocalists, that was a problem. Was not impressed with the RCA 7025s or 5751s. If anyone wants to try some of these, send me a private email. So far, the best in my system has been some Amperex Holland 12AU7s. BTW, this amp was much better with the BAT than a CAT SL1 Sig I tried (also now available).
zaikesman
3,017 posts
 
Muralman1, are you certain that the Pass amps contain no resistors in the signal path? Also, I thought the 'Super-Symmetry' topology was implemented prior to the output stage. (I too have not heard of interstage coupling capacitors being referred to as "step-up" capacitors - though I believe they are sometimes called DC-blocking capacitors.)
muralman1
1,527 posts
 
Zaikesman, sorry, that was something I got off of a review a long time ago, and I never bothered to look it up. There are resistors, a few, in line. Resistors are passive.

The two stages of Pass X amps are direct coupled.
zaikesman
3,017 posts
 
Yes, resistors are passive, and so are capacitors (plus of course transformers, and wire). And both color the signal that passes through them (as do active devices like transistors), but both are necessary to construct circuits. Since an amp's power supply is actually in the signal path (the input signal to each amplification stage serves only as a 'template' to modulate a new larger one for the output, taken from the power supply), and since all conventional amplifiers contain capacitors in the power supply, we can't really say that direct-coupled amps contain no capacitors in the signal path - only that they contain no coupling capacitors.
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