[sdiy] anti pop mosfets in minibrute

[René Schmitz]

Yes, the FET reverse diode will go into conduction at about -0.5-0.6V. 
So maybe 1 to 1.2Vpp.

If what is driving the headphone amp is 2Vpp, and the output was open 
(or light load), it could clip.

The 22R resistors form a voltage divider together with the other 22R and 
the load.

So the actual clipping level depends on the headphones connected.

Assuming you don't run this full steam it's probably good enough.

Not a great solution, but it works aparrently.


I would have used two NMOS in anti-series instead.

No need for exotic components or PMOS (which would just flip the sign) 
as discussed.


Best,

  René



On 24.04.2024 22:14, Chris McDowell via Synth-diy wrote:
> preview.png
> MiniBrute-10-OUTPUT 
> <https://hackabrute.yusynth.net/MINIBRUTE/digital-board/schematics/MiniBrute-10-OUTPUT.pdf>
> PDF Document · 339 KB 
> <https://hackabrute.yusynth.net/MINIBRUTE/digital-board/schematics/MiniBrute-10-OUTPUT.pdf>
>
> <https://hackabrute.yusynth.net/MINIBRUTE/digital-board/schematics/MiniBrute-10-OUTPUT.pdf>
>
>
> hello list, I've been looking at minibrute schematics today and I'm 
> puzzled by the anti pop circuitry in the headphone driver. it -seems- 
> like the body diode of the mosfets would conduct when the signal went 
> below 0.6ish volts (something I've run into this using mosfets for dc 
> signal muting).
>
>  From the vca page, that signal can be up to 2Vpp. 
> https://hackabrute.yusynth.net/MINIBRUTE/analog-board/schematics/MiniBrute-08-VCA.pdf
>
> What am I missing here? Is 2Vpp just fine in this case? Now reading 
> the 2n7002 datasheet I see the forward voltage of the source-drain 
> diode is typ 0.88V, 1.5V max. Did I just answer my own question? 😜


>
> Cheers,
> Chris McDowell
>
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to:Synth-diy at synth-diy.org
> View archive at:https://synth-diy.org/pipermail/synth-diy/
> Check your settings at:https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Usemarketplace at synth-diy.org


-- 
--
synth at schmitzbits.de
http://schmitzbits.de
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20240425/f39ddc10/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: preview.png
Type: image/png
Size: 73309 bytes
Desc: not available
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20240425/f39ddc10/attachment.png>