Devialet for Wilson Audio Sasha 2 Speakers

@georgehifi 
"Doesn't" is a present tense term. Threshold gear is hardly "modern era" stuff. Nothing that's come out of Pass Labs or First Watt features BJT outputs or inputs. Everything from Pass Labs and First Watt uses MOSFET, JFET, or SIT output devices. 

Even so this sort of impedance and -phase angle load that the Sasha presents in the bass needs a lot of current to drive, and BJT’s do that better than Mosfets can.
https://www.stereophile.com/images/archivesart/710Wilfig1.jpg

Cheers George

I get it, but I have no idea where you get this idea a huge bank of FETs don't get the job done. I'm listening to an F5 I built right now and the whole reason Nelson designed it with 3 way current limiting is because those MOSFETs will switch the full power supply current in tiny fractions of a second. My Focals aren't as brutal as those Wilsons, but with a low point of 2.8 ohm and a -56° phase angle at 4 ohm, these will draw some current. This F5 drives them with absolute ease. If it struggled at all I'd be seeing serious rises in output device temperature which isn't happening. I see maybe a 5°C rise under the most taxing volume and material. I have no doubt an INT-60 would have just as easy a time with the Wilsons. 

Device for device a BJT will out current a Mosfet.
Given powersupply conditions are right for both. Sure 10 complimentary pairs of Mosfets, will do a certain "current job".
But 10 complimentry pairs of BJT’s will do a far better "current job".
That is why Krell and Agostino and others use BJT’s, as they want to be able to almost double the wattage for each halving of impedance load all the way down to 2 or even 1ohm, to drive things like Sasha's and Alexia's

Cheers George

@georgehifi 
The MOSFETs in an F5 do nothing but swing current. They operate in common drain mode and provide no voltage gain whatsoever. There is no "almost" about them doubling current with a halving of the impedance. That's exactly what they'll do until they melt or the power supply taps out. Pass Labs claims their amps will drive any load down to a dead short, though the protection circuitry tends to kick in just below 2 ohm, but their designs are that rugged. I wouldn't try putting my F5 up to driving a dead short because it's meager single pair of outputs wouldn't handle that well at all, but something like a well built F5 Turbo V3? Yeah... That thing would definitely drive 1 ohm loads all day.
There are a number of modes you can operate a transistor in to get gain out of them. When you operate them in a mode where they amplify voltage and amperage you tend to get an amplifier that's more sensitive to a reactive load because fluctuations in the voltage also mean fluctuations in the current. Most, if not all of Pass Labs amps, operate the output stage as a source follower; all it does is provide current in support of a prior voltage gain stage. 
No offence, but it doesn't sound like you have much actual working knowledge of how these devices work. I understand some people like the sound of BJT amps. There's nothing wrong with that. They're definitely different than FET amps just like tubes are different. You assertion that a FET can't swing current like a BJT can is demonstrably false though. Not only can they do it, they generally do it much better.