200 kHz AB amplifier

[stinius]

I'm not able to see your schematick could you post it here.

Is it for a Sonar (ping) or something simmilar?

 

[OldDIY]

This AMP should be AB class, it has to drive an acoustic underwater antenna, with fixed amplitude, and narrow bandwith into 200 kHz (190/210 something like that). When I say pulse I don't mean a square wave, so we have to consider a sinusoidal signal, a simple case.
For DC stability I mean 0V into the output without input signal. Actually with the first schematic I posted, this DC point is instable, I don't know why.

Schemes do not open 🙁
Include a film capacitor and series resistor on the output
1-4 ohms in series with the load 🙂

 

[thimios]

Have a look here. Slewmaster - CFA vs. VFA "Rumble"

 

[mtx489]

Old schematic, not well working:

AB-AMP-schema-OLD — ImgBB

New schematic, improved version, still to make or change totally:

AB-AMP-schema — ImgBB

 

[egellings]

Why such a high frequency capability for an audio amplifier?

 

[JMFahey]

It´s not exactly "an audio amplifier" but a test instrument, to drive some kind of ultrasonic transducer.

 

[mtx489]

Yes, but I suppose it will work only in a pure resistive 20 ohm load, so let's consider a 200 kHz sine wave input.
I attached my last Spice schematic, plase if someone can play with it to find some critical issue is welcome.
I had a more expert suggestion to be sure this topology is or is not a good choice.