bootstrapsCCS+T-TMC

[dadod]

Hi Dadod,
I sent an Email this morning. No reply yet.
I wonder if it ended up in your Spam bin?

I've sent answer email one hour ago, and now again.
dado

 

[AndrewT]

Hi D,
got them.
They were in my old Email.
the .asc opens and runs on the first I tried.
Thanks.

 

[Andreas B]

Hi Dado

You have a PM

Regards
Andreas

 

[sumeshak]

Darington VAS resistors

Dear Sir,
Can you lease expain how do we chose the resistors R14 and R19?
In Text books , the collector is direcly gounded.
Thanks and regards,
sumesh

Here is last schematic and bill of materials.
dado

 

[dadod]

Dear Sir,
Can you lease expain how do we chose the resistors R14 and R19?
In Text books , the collector is direcly gounded.
Thanks and regards,
sumesh

Sorry for late answer, I've been with no internet util now.
R19 is protection resistor against overload, that Self did badly connecting collector directly to the ground.

 

[RCruz]

Oh, I forgot one informatio that could be intereting.
VAS current fluctuation with simple bootstrap was cca 13% and down to 2-3% with this improved bootstrap.
As expected the low frequences sound was very firm an deep(normal for bootstrap)
dado

 

[GEirin]

Hi all.
I recently discovered this thread. Very interesting.
Dadod:
Could you tell me how R2 is calculated?

 

[dadod]

Hi all.
I recently discovered this thread. Very interesting.
Dadod:
Could you tell me how R2 is calculated?

If you read this thread from beginninig, that deplation mosfet defines the VAS current, it is current source. R2 defines that current. Look in the mosfet datasheet.

 

[printnik]

Hi. I'm learning the programm LTspice. I completed this circuit with other transistors.

 

[printnik]

DADO-TMC-T_bootfetCCS_2.asc

 

[donovas]

Hi i have downscaled this circuit for +-15v to be used as a headphone amp. Did without the jfet ccs for now. The thing sounds wonderful. However at +-v10 supply i get rail sticking. Offset is at 0.5v and no sound. Tried increasing ccs resistors ect. but no success. I havent learned ltspice yet so im in the dark

Any tips on how to get it to work at that low v?

All small transistors are bc327 337, output bd139 140. Gain x3

 

[printnik]

Any tips on how to get it to work at that low v?

 

[donovas]

Wow thank you!

I see that youve added some bells and whistles. In order to simply things so that i can p2p on my existing pcb, which components are responsible for making low voltage operation possible? Im thinking R41 R30 and their adjascent components.

Thank you again.

 

[printnik]

D11 - 4V7

 

[dadod]

This is not anymore bootstrapsCCS

 

[donovas]

Right. I omited that in my build because i wasnt sure if i'll like the sound. Im planning on adding it later