Iroquois
I am very pleased with this design.
But be aware this amplifier only exist in SPICE simulation.
Supply shuld be 2x18VAC transformer giving like +/-24VDC.
THD at 1 Watt in 8 Ohm is like 0.00035%.
Max output in simulation is 25 Watt.
Upper frequency is like 1.3 MHz, so a lowpass filter should be put at the input.
Enjoy!
I am very pleased with this design.
But be aware this amplifier only exist in SPICE simulation.
Supply shuld be 2x18VAC transformer giving like +/-24VDC.
THD at 1 Watt in 8 Ohm is like 0.00035%.
Max output in simulation is 25 Watt.
Upper frequency is like 1.3 MHz, so a lowpass filter should be put at the input.
Enjoy!
At post #25 and 26 of this thread:
I have tried it and with OPA 1655 it is about 0,0008 % dist.
It should work better. So try with another OP without the rail to rail output..
It does not work well with lateral fets.
It is easy to rearrange it with floating PSU and then you can have any drive voltage.
PM-AB2 MOSFET amplifier with error correction and low distortion
you can find how jxdking optimised this amp. I dont think it is possible to make it better than that.I have tried it and with OPA 1655 it is about 0,0008 % dist.
It should work better. So try with another OP without the rail to rail output..
It does not work well with lateral fets.
It is easy to rearrange it with floating PSU and then you can have any drive voltage.
You can implement Error Correction with this output stage.
The idea of MOSFET with Error Correction originally was from Bob Cordell’s paper, but I found the original implementation was very cumbersome. My design was originated from @PMA post. That thing in his post is heavily underrated. I actually built one this year with some minor changes.
It uses the the bias network to do error correction. It is equivalent to CFP with MOSFET output, but it can output from rail to rail, with help of the bootstrapping.
The example below is +-14Vp into 8 Ohm with only +-15V supply voltage. You can see the distortion is low. Note that you could put opamp at the front and wrap NFB around it to reduce distortion farther.
[Edit]Final Version:
The full schematic.
The example below is +-14Vp into 8 Ohm with only +-15V supply voltage. You can see the distortion is low. Note that you could put opamp at the front and wrap NFB around it to reduce distortion farther.
[Edit]Final Version:
The full schematic.
The idea of MOSFET with Error Correction originally was from Bob Cordell’s paper, but I found the original implementation was very cumbersome. My design was originated from @PMA post. That thing in his post is heavily underrated. I actually built one this year with some minor changes.
