Mosfet amps A true compromise betw. tubes and SS?

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.

Muralman1: O.K. now I see your system setup. As for the tubes, I did like some 1960's Mullard 6DJ8 I put in an ARC LS25 preamp I owned a while back. (Currently I skip a preamp, by using a Wadia CD player only). But in the Llano amp, such Mullards don't seem quite as grainless and refined in the treble as some other classics like Amperex. I'm still experimenting with different types of NOS tubes, and not quite satisfied yet. The Llano's input tube stage provides all the voltage gain in my system, so the tube choice is everything. E.g. 7025/12AX7 are quite musical but lack focus, 5751 have more focus but sound a little muddy, and 6922/6DJ8 character varies wildly with manufacturer. I'm looking for a liquid and grainless midrange with dimensionality, super-sweet treble (to tame the Maggie ribbons), and tight bass. Of course, I guess that's what most people want. I haven't yet tried some of the ones you listed like Siemens, Telefunken, and Sylvania, though. BTW, is your Jolida an integrated amp?

The Jolida JD-100 is a cd player. I hate to harp on amps again, but according to experts I trust in the field, the Pass X amps are the cleanest amp built due to it's DC circuitry throughout, accomplished by not using the usual amp builder's crutches, like detail robbing feedback and step up capacitors. Nelson's ingenious utilization of his super symmetry finishes the job. With the help of the tube cd player, I enjoy all the points on our collective wish list, except perhaps Krell like bass slam. That's not something I miss.

Given the Pass amp is colorless, I can control the sound with my cd player tubes. Like you, I find tube selection critical for my listening enjoyment. The 12ATX7 Mullards CV4004 tubes were not grainy, and were quite musical. The trouble I had with them was they starved my system of micro detail. Mullard tubes are visually flimsy. JAN Phillip tubes gave better detail. I am using 1950s Sylvania 5751 tubes which are purposely built to defeat microphonics. At $45 apiece, (if you can find them) they are a bargain Telefunken, full liquid mids, sweet highs, and a seductive bass.