Coming from here, https://www.diyaudio.com/community/threads/help-with-lat-fet-schematic.424463/
Some members advised to bootstrap an opamp for higher(+/- 32V)output swing. Further I like to bring down THD + N as low as possible.
Below the schematic I combined from several threads.
Can this work?
Some members advised to bootstrap an opamp for higher(+/- 32V)output swing. Further I like to bring down THD + N as low as possible.
Below the schematic I combined from several threads.
Can this work?
R14 R11, could be bootstrapped.
Q2, Q3 could be replaced with a simple emitter follower.
Other than that, it should work.
Q2, Q3 could be replaced with a simple emitter follower.
Other than that, it should work.
Thanks.
I looked for emitter follower but I am curious if the opamps bring lower thd + n.
About bootstrap R11 and R14, what is there the advantage?
I looked for emitter follower but I am curious if the opamps bring lower thd + n.
About bootstrap R11 and R14, what is there the advantage?
Apparently so 😉 Haven't tried anything further with it yet. This is at the point of clipping i.e. max output.
You will need to use your own models for the FET's
Thanks a lot, I must learn how to use ltspice.
When replacing R11/14 with two 5k6 resistors and one 100uf capacitor( for each) from the middle to the output(bootstrap). Can I then have even more output swing?
When replacing R11/14 with two 5k6 resistors and one 100uf capacitor( for each) from the middle to the output(bootstrap). Can I then have even more output swing?
This file includes the FET models embedded into the sim and should just click and run. Why not download LTspice and give it a try 🙂
Altering the resistors alters the bias current. 33k would give near zero bias although the amp would still run OK.... just with no bias current.
Higher voltage opamps are a possibility but also remember the subjective difference a few extra volts of swing makes would not be noticeable.
Last one for today 😉 At max output.
This sunday spend time to learn using ltspice.
And make a version with transistor bootstrap.
There is not much difference for the THD with the opamp version.
I will make a universal PCB. It will have a layout for opamp or transistor bootstrap and several filter options.
I tried also to import/use other opamp/fet models but this was not a succes.
And make a version with transistor bootstrap.
There is not much difference for the THD with the opamp version.
I will make a universal PCB. It will have a layout for opamp or transistor bootstrap and several filter options.
I tried also to import/use other opamp/fet models but this was not a succes.
Excellent, well done 👍 Models aren't always the easiest things to work with.
The models as far as I know are behavioral models rather than an opamp circuit made up of actual components... if that makes sense. It will be interesting to see if real opamps match the simulated performance.
The models as far as I know are behavioral models rather than an opamp circuit made up of actual components... if that makes sense. It will be interesting to see if real opamps match the simulated performance.