Mosfet amps A true compromise betw. tubes and SS?

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

Muralman1 - Yes I can see how tube pre + Pass might work well on Apogees. That combo didn't quite do it for me with my Maggies (3.6/R), but of course different systems, cables, listeners, etc. Not just midrange aspects, but a tube preamp seems to ripen up the bass too much for me. I agree that pure tube amps on magnetic planars can sometimes sound slow. (One exception is the Wolcott 200W monoblocks I once home-auditioned....nice but a bit pricey).

I actively biamp my Maggies in order to optimize the bass versus mid/high performance separately. Experimented a lot with various SS amps, and some SS/tube combos for the two amps. Finally settled on using 2 Llano Trinity amps because of (1) their control of the panels, (2) their sonic "tuneability" by rolling the input tubes, (3) just fewer tubes to replace than pure tube amp, and (4) overall reasonable cost of the Trinity amps. (The choice of the 2 input tubes makes such a huge sonic difference with Llano that one must be careful in auditioning one of these amps.) E.g. I like 6DJ8 in the mid/high amp (for detail, imaging) along with 12AT7 in the bass amp (for full yet tight bass). All NOS of course (Maggies are too revealing for anything less).

I'm not sure whether the Trinity is pure class-A either. I use the Trinity 300W for bass and the 200W for mid/highs. They both run too hot to rest your hand on, though. (Definitely not "cool-running" amps). But seems like a 300W class-A amp should get even hotter than this....

oops, Ral, I gave you the wrong idea. I tried a tube pre (Sonic Frontiers) but found the solid state Aleph P more to my liking. Like it's brethren, the X amp, it has a relatively benign sonic stamp. I'm controlling the character of what I am listening to with a Jolida JD-100. With the correct NOS tubes installed, Telefunken, RCA, Siemens, Syvania, this is an inexpensive musical wonder. Ral, I wonder if you have found, like me, Mullards are poor sounding in a revealing system.

By the way, Maggies are great. Biamping is the norm for Apogee users as well.