This is for Georgehifi especially but others can chime in.

@georgehifi 
Since you're hung up on the doubling power, which you say is impossible, I'll tell you how to do it. Remove the source resistors in the source follower output stage of a MOSFET amp. Guys do that all the time in the DIY world, but you practically never see it in production gear because the line between stable and unstable is pretty fine. You don't really want to try that with BJT's because of their more aggressive thermal runaway characteristics. But, if you use MOSFETs with a big enough heatsink, there's a point of equilibrium and you can build a fairly stable amp. 

You two really need to update your semiconductor knowledge.


Upvoted by, MSEE Electrical Engineering & Circuit and System, Master of Science in Electrical Engineering (2015) and M.S Electrical Engineering, University of Southern California (2017)

Pros for BJT:
"BJT’s at the same physical dimensions and price can usually give you a lot higher speed, as they have very little input capacitance.

BJT’s can give you a lot higher gain. Just take a bunch of components and compare them, and you’ll find the BJT’s give you better gain characteristics and therefore require fewer gain stages.

BJT amplifier stages are much more linear than MOSFET amplifier stages, as the gain doesn’t depend on the bias voltage. This gives better fidelity.

BJT’s are capable of handling higher output currents for signal outputs and can have lower output impedance. In amplifiers intended to drive a low input impedance load or deliver significant amounts of power, this is a huge advantage. Many of the highest quality op amps are made with a BiCMOS process using a BJT pair for the output buffer stage."



Cons for MOSFET:
"Not as high of fidelity as BJT, since the gain will vary slightly as you increase the input voltage (that is, it will generate some very weak harmonics).

Input capacitance. The higher the gain, the greater the input capacitance thanks to the Miller effect.

Can’t drive a low-impedance load very well.

Low gain per part, which often means more amplification stages are necessary for higher gain, even when using advanced design techniques. Each amplification stage adds noise -- that is, you can never, ever get a better signal-to-noise ratio at the output than at the input."



I believe the OP has everything he needs, and doesn’t need the BS from the F5/Mosfet lovers, which I’ve heard and are great amps, if used within their comfort zone with preamps with high’ish gain and speakers not too low in EPDR load impedance’s and moderately efficient, because of wattage limitations.

Hope you got everything you needed bubba12
Unfollowing this corrupted thread.
Cheers George

@georgehifi 
Oh.... We're going to just resort to half-truths and omissions, huh? Just going to ignore the thermal issues, the low base impedance which is a much bigger problem than a little gate capacitance. And how do you make a simpler circuits with devices that basically demand a driver stage? 

I need opinions on the Odyssey Stratos Extreme mono amps for powering the Dynaudio C-1 Platinum speakers. I have purchases a set based on things I’ve heard.

bubba12 OP156 posts01-25-2018 6:37pmI need opinions on the Odyssey Stratos Extreme mono amps

I’ve come across some Odyssey amps, a stereo and the mono-block version of it here in Australia, that a friend bought in who was going to be the Au agent for them.

I can’t remember which ones they were but they were the upper end of the range.
We listened to them, with a group of our audio society friends and were all in the opinion that the stereo version sounded better than the monoblocks, even through the very hard to drive Infinity Systems Renaissance 90 Signatures, oldie but a goody.

After that listening session, we peaked under their skirts, and what I pointed out to the potential agent was that the monoblocks were just bridged versions of the stereo one.
Now I don’t know if this bridging of the stereo ones for the monoblocks is done right through the range.

But if you post a photo of the inside on one of the many free image hosting websites I can let you know, if they are just bridged stereo’s or true monoblock amps.

Cheers George