X = bridged = push pull ? ...

[Bernhard]

First idea:

As a real harcore audiophile, I will move to Sahara, built a solar powerplant (cost and ripple free energy ) and idle @ 4A per Fet

 

[Bernhard]

1. The current swings of the master could be made smaller than that of the slave, so the master would stay more in the linear area.

I think thats also what the Aleph does.


2. What about putting master Fets in series

If we idle @ 4A per Fet, it is far too much dissipation @ 24V rails, but when 4 Fets are in series, its 25W per Fet.

I tried 2 Fets in the sim, no problem.

 

[AKSA]

Bernhard,

Your plan is a good one.

However, if you want more linearity on the master fets, the upper devices, why not drive them in CFP?

This way, with output taken from the drain of the mosfet to accord with the emitter of the driver (possibly a bipolar), then the linearity of the mosfet becomes insignificant compared to the linearity of the driver.

Cheers,

Hugh

 

[Bernhard]

Hugh,

what is a CFP ?

Could you draw a little schematic ?

I really can not follow your description of your idea.


Another idea to keep the dissipation down:

Feed the output stage from a variable switching power supply...


Greetings, Bernhard

 

[AKSA]

Bernhard,

A CFP is a Complementary Feedback Pair, sometimes called a Sziklai Pair.

For the master fet it would be a bipolar NPN with collector to gate, emitter to drain, and the mosfet source to rail. The collector of the NPN is feed via a resistor to gate (gate and collector are joined).

A switching, or commutating rail, is not such a wonderful idea IMHO because it introduces the small noise of this switching to the power side of the fet. Not good.

Cheers,

Hugh