Opamp based power amp

[UltimateX86]

Hello

Do you have the model of lateral mosfet ALFET 16A ?

Thanks

 

[Kastor L]

I ordered LT1363 and 1223 from Digikey. Will build real circuit soon.

My new schematic with LT1223 and 10p !!

THD (28Vp swing) (100W 4ohm)
1 k 0.000003% !!!!!!!!!!!!!!
20 k 0.000475%

Yes, the numbers are too good to be true.

That is what I am after - building a real one. Real circuit inferior to simulation or even not working is a norm. We can then learn more (learning from fails). The opamp models are most likely macro models instead of transistor level. Nevertheless, IMHO we have something to start with.

Very nice. Is someone making a PCB?

This experiment looks interesting, I'm a novice in this area but I'd love to try.

 

[Calvin]

Hi,

You may take a look at the new ADA4700-1 from AnalogDevices.

jauu
Calvin

 

[UltimateX86]

HI, no pcb for the moment, I work on a zero feedback buffer before HV OPA

Thanks Calvin for the reference !

 

[Kastor L]

How do I order a PCB for this project? Any advice? I've never ordered a PCB before.

 

[Kastor L]

I change to (K)2SC3503 / (K)2SA1381 from CordellAudio.com - SPICE Models

Yes I will try in real life ... but :

0.000000 % 1K 100W 4ohm

Is this fantasy

 

[cliffforrest]

The problem is that all internal currents and current fluctuations that may not be related to the signal are put forward to the OS, that is why I would say it is a bad idea. There are multiple way to convey the op-amp output signal to the OS and that will be a much cleaner way to do it.

Please explain more about these supposed "internal currents and current fluctuations". I presume you are referring to inside the OA?

Reflect that, in terms of current, there are only V+, V- and OP pins ....

It is just that I have used floating op-amps in many different configurations with great success and it worries me to learn that they cannot work!

 

[manso]

Please explain more about these supposed "internal currents and current fluctuations". I presume you are referring to inside the OA?

Reflect that, in terms of current, there are only V+, V- and OP pins ....

It is just that I have used floating op-amps in many different configurations with great success and it worries me to learn that they cannot work!

The audio amplifier world is full of myths.

 

[FdW]

Please explain more about these supposed "internal currents and current fluctuations".

No 🙂 maybe a book or two is going to help.

I presume you are referring to inside the OA?

Yes.

Reflect that, in terms of current, there are only V+, V- and OP pins ....

What? 🙂 and Americans where never at the moon.

It is just that I have used floating op-amps in many different configurations with great success and it worries me to learn that they cannot work!

Good for you. And I never said that it would not work. It just is not the best way to do it IMHO

 

[yutorho]

has anyone actually made this amp?

 

[jaycee]

Looks like a lot of the "magic" here was simulation missing out the fine points. Anyway the overall topology is the same as the Mark Alexander power amplifier described in an Analog app note AN-211. The IGBT output stage shown there can easily be replaced with MOSFETs (or indeed BJT's)

 

[selwe]

Did this work afterall?

Fixed schematic...
That PCB I made that day was prototype. I just wanted to try if its possible to dye PCB's with just ink and boiling... Seems to work.

Have you built it afterall? Any conclusion? Does it worth? Tnkx.