Choctaw - 10 Watt Amplifier, 1 Opamp + 2 MOSFET

Hi, you can use something like this:
1000018755.jpg

You chose type and number of diodes to be close to Nch mosfet Vgs. 1n4001, red led, stuff like that. Zeners are reported too noisy but in this application probably nobody will notice.
Like this opamp out will be close to output V
 
It will still not work with vertical mosfet, you still need to thermally compensate them.
Most of those might turn into negative temp coefficient but at burning currents, much more than you need for class A, and then only if and when.
Just my opinion.
See photos on my post #236, this can't be so difficult to do, even with few euro budget
 
also im intrested if that could worki heard that you can use some sort of magical dc voltage multiplier to achieve a higher voltage swing
Circuit post#309 will work, this diode I don't know but it should have voltage drop close to the Vgs of N channel.
28k resistors are too big IMO as they give just 0.5mA bias current. 2mA or more is more appropriate I think. For such small amp TO220 mosfets(like IRF 53x) are enough, it will reduce current needs for drive due lower Cin, besides they are cheaper.
PS, R2 needs to be a pot.

For increasing voltage swing bootstraping can be used (2 electrolytic +2 resistors needed in addition) ,
Never seen voltage multiplier in such function, like post #310

But this is whole different amp, might be you open own thread on it so this one is not crowded with off subject?
 
Hi

Is anyone interested in my prototype?
I'm selling it because I'm running out of space ;-)
I'm selling a PCB soldered as in the picture - without output transistors and input capacitors

The rest of the components from trusted sources

Large Elna - taken from the amplifier, measured - functional

Send PM
 

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