Filtering switch mode power supply

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mpx
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Filtering switch mode power supply

Post by mpx » Mon Feb 22, 2021 10:35 pm

Hello necks

Is it possible to filter a switch mode power supply output? One I have is causing havoc with pilot tones, ringing noise. God only knows what spurs it might be generating. Wondered if I can cure it with some filtering caps or something.

Cheers

radium98
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Re: Filtering switch mode power supply

Post by radium98 » Tue Feb 23, 2021 7:05 am

try some ferrites or beads coils with decoup caps

mpx
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Re: Filtering switch mode power supply

Post by mpx » Tue Feb 23, 2021 7:38 am

Decoupling 0.1uF?

radium98
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Re: Filtering switch mode power supply

Post by radium98 » Tue Feb 23, 2021 12:05 pm

have to try many values 100 , 10 and 1 nf with some vk200 to remove thoses EMI

mpx
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Re: Filtering switch mode power supply

Post by mpx » Tue Feb 23, 2021 1:05 pm

LC in series (psu-L-C-out)?
Which type of vk200? Or can I use a few turns through a regular ferrite tube?

I read it is quite difficult to clean up smpsu outputs completely

Thanks

nrgkits.nz
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Re: Filtering switch mode power supply

Post by nrgkits.nz » Wed Feb 24, 2021 9:08 am

Use Meanwell power supplies, I’ve never had any problems with them.

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teckniqs
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Re: Filtering switch mode power supply

Post by teckniqs » Wed Feb 24, 2021 10:27 am

Yeah I think it would be much easier to just replace the PSU. I've tried using microwave link box from laptop charger and it made a high pitched whining noise over the audio but with another laptop charger it was fine (all I had at the time).

mpx
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Re: Filtering switch mode power supply

Post by mpx » Wed Feb 24, 2021 4:11 pm

I might replace it with a linear psu.

Do the Meanwell ones need anything on the output?

LeeCavanagh
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Re: Filtering switch mode power supply

Post by LeeCavanagh » Wed Feb 24, 2021 10:29 pm

mpx wrote:
Wed Feb 24, 2021 4:11 pm
Do the Meanwell ones need anything on the output?
No they dont, but they are also not the only brand that dont need extra filtering, you could find others cheaper, but mean well do have the best rep dont they.
Sony ST 920 QS

mpx
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Re: Filtering switch mode power supply

Post by mpx » Wed Feb 24, 2021 10:35 pm

Thanks :tup

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