Cello One. Good Amplifier 15 Watt with TMC and Laterals

[lineup]

Cello One
All data comes from SPICE simulation.
I leave building this amplifier to diyAudio members.
I can not build it.

Max 15 Watt into 8 Ohm Class AB
TMC compensation
THD 0.00005% at 1 Watt
Easy to find components are used

 

[lineup]

This is the squarewave at 1kHz.

 

[adason]

Now that's as square as it gets!

 

[PMA]

It is necessary to build the circuit to evaluate the square response. And it is not a good practice to leave it on a builder, if one starts the project thread.

 

[lineup]

I beg to differ, @PMA
There are a great many threads of projects that started without building.
I have posted a few such threads.
And some people will like it and build together.
Now @PMA you do it the other way. You have the opportunity to build and publish. That's fine.
I have no possibility to build.

 

[lineup]

Now that's as square as it gets!

I will post squarewave 10kHz, too.
But the upper bandwidth is only 400kHz.
On the other hand that can be good for to make a stable amplifier.

 

[adason]

Don't be so harsh Pavel, we know lineup does not build. But his designs were built by others and worked great. I am using one of his small classA amps with bookshelfs for testing preamps right now and it makes sweet sound.

 

[pbilous]

What about something like this but with 100W into 8 ohms?

 

[PMA]

Then it is a serious design, serious amplifier and you have to solve properly layout and especially PCB - ground returns, feedback return point, more output pairs, stability into complex load etc. Then it is not a toy anymore.

 

[pbilous]

Maybe at least 50W?
Can raise power supply voltage to 35V and use ECX20N20 / ECX20P20 dual die laterals.

 

[PMA]

Yes, with 2 x 35V supply it should be possible to stick with one pair. With 2 x 55V supply I get 2 x 250W/4R and 2 x 150W/8R and the amp starts to be quite complex, if I want to stay at a safe side. But it is a dominant pole compensation, not TMC.

https://pmacura.cz/DIY_250W_4ohm_amplifier.html

 

[Aridace]

I beg to differ, @PMA
There are a great many threads of projects that started without building.
I have posted a few such threads.
And some people will like it and build together.
Now @PMA you do it the other way. You have the opportunity to build and publish. That's fine.
I have no possibility to build.

Sims have to provide enough info. Square wave in & out doesn't. What matters in that case are the waveforms within the feedback loop which might reveal clipping / overshoot. The AC voltage over R13 would provide that info.

 

[pbilous]

Yes, with 2 x 35V supply it should be possible to stick with one pair. With 2 x 55V supply I get 2 x 250W/4R and 2 x 150W/8R and the amp starts to be quite complex, if I want to stay at a safe side. But it is a dominant pole compensation, not TMC.

https://pmacura.cz/DIY_250W_4ohm_amplifier.html

Looks classy. Fun stuff!
Have you tried two pole compensation?

 

[pbilous]

No small degeneration resistor at the U6 emitter, huh? Looks like good enough without?

 

[PMA]

Have you tried two pole compensation?

I did, in another projects. It improves distortion at high frequencies, but it makes stability a bit worse, even if you have "enough" stability margin in loopgain analysis. Audibly, it brings nothing, there is no difference. After decades in this hobby, I do not believe any sighted test opinion. The test must be properly done double blind, with perfectly matched level, to have some significance.

 

[HAYK]

Cut R12 and see if it makes any difference.

 

[lineup]

This is the AC Analysis.
Bandwidth is 3Hz to 400kHz.

 

[lineup]

This is the Max Watt Output while THD 0.000%.
15.762 Watt

 

[TNT]

Why write 0,000%? It could be 0,00099 which means that it is 0,001 really.

It is a simulation - and as such VERY uncertain - to play with decimals leaving the actual value out, pretending that it is 0 (?) is silly - nobody here is fooled by that - you must realise that. Be open - play no games.

//

 

[lineup]

Thanks for posting a question.
THD is rounded up or down for 3 decimals.
In this case the actual value could be anything lower than 0.00050%