what about diamond buffer MOSFET?

[peranders]

I like C2, I can't believe I never thought of it before.

This is not particular unusual. Has been around for decades in fact.

 

[Tim__x]

I have seen it applied to other biasing schemes. But for some reason I never though about adding it to a diamond buffer.

I wasn't saying it was ingenious or new. Really I was just pointing out my own stupidity in not thinking to use it with this topology.

 

[padamiecki]

This is not particular unusual. Has been around for decades in fact.

is it speed-up-switch cap?

 

[peranders]

This is a simple RC filter for the supply voltage. R115 is the "R".

 

[Tim__x]

There seems to have been a misunderstanding, I'm talking about C2 in the second schematic, the one that connect the bases of Q3 and Q4 in the diamond buffer, not the LTP.

 

[PMA]

Regarding MOSFET diamond buffer, I simulated this power buffer, results looked perfect. It is possible to use CCSs, if anybody wanted.

 

[PMA]

Like the second schematic on this page, http://web.telecom.cz/macura/classa_20w.html?

I like C2, I can't believe I never thought of it before.

The C2 (470uF between base of Q3 and Q4) is extremely important. It helps the power buffer to transit class AB, if needed. It also considerably reduces distortion and increases output voltage swing.