Simple Symetrical Amplifier

[Lazy Cat]

You're thinking about something like that.

[wahab]

Originally Posted by Lazy Cat

It looks in this concept with 8 transistors, lateral MOSFET output's would give the best THD figures, loading the VAS less than other versions.

MOSFET driver is another option, maybe ...

Laterals would perfectly suit if...they are driven by an EF stage,
as the high frequency THD would rise a lot if there s no bufferisation
of the VAS, even if it has a relatively high standing current.

Also, two pairs would be necessary to have good THD distribution.

That makes a lot in respect of the projected simplicity , but high
perfs are not achievable with low component count , unless
one use a dedicated high perf IC driver.

[Joachim Gerhard]

Yes, that looks good to me.

[Joachim Gerhard]

I also thought like Wahab that the Szikley is around the output Fets, so one driver stage more. Yes, this gets us more away from the simplicity of the first version.

[wahab]

Originally Posted by Lazy Cat

You're thinking about something like that.

Somewhat like this..

[Lazy Cat]

Originally Posted by Joachim Gerhard

Yes, that looks good to me.

OK, that's good.

I know we could easily go to 20 transistors version in a split second, but that maybe will happen in another thread, another time.

So, we have to stay at most 8 transistors only concept, this ensures discrete symmetrical circuit simplicity, on the other hand on us is to find the best sch configuration within these limits for the best performance. It sounds like a challange to me.

[Lazy Cat]

Originally Posted by wahab

Somewhat like this..

Nooooo, too many transistors according to thread theme.

Besides this is not somewhat Joachim meant. Check my last sch, DRAIN output ...

[wahab]

Originally Posted by Lazy Cat

So, to stay at most 8 transistors only concept, this ensures discrete circuit simplicity, on the other hand on us is to find the best sch configuration within these limits for the best performance. It sounds like challange.

Either linearity or OLG or both have to be improved for better perfs,
but in all cases , this is possible only with additionnal components...

[Joachim Gerhard]

I would then turn around the Fets ( post 205 ) but that may create oscillation problems.

[wahab]

Originally Posted by Joachim Gerhard

I would then turn around the Fets ( post 205 ) but that may create oscillation problems.

It is quite possible , stability is not unconditional..