Another EMI filter

Jump to Latest
#61
Grauwacke said:
So voltage level and impedances could be seen as roughly comparable in both sets, but, of course, are far from any real world situation. Btw, are impedance measurements done at 230V AC right into the MHz region available?

"So conclusion could be that they do filter and provide galvanic isolation but are best helped by an added mains filter and an RF proof PSU.
... A pollution that changes randomly so why not fight it somewhat at all fronts?"

Fully d'accord with you.
Click to expand...
Thank you.
gabdx said:
gabdx said:
OHM, 500va, 1000Va, watts, Mhz, 60hz into 20khz and 20 hz. 2khz....a 2kvA and 3kvA, using 250vA is not a good idea.
Click to expand...
Click to expand...
It is an even worse idea to abuse terms the way you do. Man it hurts my electrical soul. If you can’t do the talk you can’t do the walk. Sorry.


Enough threadjacking. Please let's go back to the topic "DIY EMI filter for power supply" and the board. Where is our friend Mimiragon?
 
Last edited:
  • Like
Reactions: Mimiragon
#62
.
1000027631.jpg

I only use Vitroperm coils from the vacuum melting plant, in my opinion these are the best





This is my homemade EMI filter. The upper board contains the filter for my amplifier, the lower board contains a replica Thel filter for the network player, and I use the Thel board as the DC filter.
1000010366.jpg


On the left of the photo are a Chinese DC filter and a Chinese EMI filter. On the right are the Thel circuit boards.
1000007209.jpg
 
#66
Dies ist nur ein Beispiel.
Ich nutze USB nicht von meinem Computer. Es dient als Filter für meinen Netzwerkplayer und Computer. Alibaba, eBay und Amazon bieten große Gehäuse mit vier oder acht Anschlüssen für Netzfilter an. Dabei handelt es sich um Aluminiumgehäuse. Rack-Gehäuse sind ebenfalls eine Option. Ich bezweifle, dass man für jedes Gerät einen DC-Filter und einen EMI-Filter in eine Steckdosenleiste integrieren kann. Mehrere in Reihe geschaltete Leisten wären kontraproduktiv.
Besser wäre es, den Filter direkt in das Verstärkergehäuse einzubauen.


This is just an example.
I don't use USB from my computer. It's a filter for my network player and computer. Alibaba, eBay, and Amazon offer large enclosures with four or eight outlets for line filters, and these are aluminum enclosures. Rack-mounted enclosures are also an option. I doubt you can integrate a DC filter and EMI filter for each device into a power strip. Multiple strips in series would be counterproductive.

It would be better to build the filter directly into the amplifier enclosure.

1000012164.jpg
1000027934.jpg
1000027275.jpg
1000028656.jpg
 
Last edited:
  • Like
Reactions: gabdx
#67
Yeah, I get the idea. Man does it makes a difference in the soundstage...

Just the chinese filter module, I use the 20A one just like that for now without any case for the USB emu0404

The passive transformer (I replaced the stock switching one) is now very happy and the dac starts without rebooting for 10 minutes like before.

This is a MUST and cleaver to install it in the Amp chassis so that you bring the amp anywhere you are sure the Toroid is protected.

My problem now is that the computer is sending video card and cpu noises inside the dac and it goes through the input through pollution of the power supply . It is only from the USB line and originates in the computer.

I am looking for options but tonight I could listen back to what music sounded 20 years ago.

I think I am going to cry. This is so emotional moment after what they CLF, Switching cars power supply etc have done to the Grid.
 
  • Like
Reactions: Franz Shottky
#69
A few links for accessories and components.
The 2.5mm² shielded cable seems like a good choice to me; the connectors are made of aluminum, which improves shielding.


https://www.ebay.de/itm/176474493010?mkcid=16&mkevt=1&mkrid=707-127634-2357-0&sss po=93DDj7qwR8C&sssrc=4429486&ssuid=HIkhxjHJTLq&var=&widget_ver=artemis&media=COPY

https://www.ebay.de/itm/166783075160?mkcid=16&mkevt=1&mkrid=707-127634-2357-0&sss po=k80Mu6A-TbK&sssrc=4429486&ssuid=HIkhxjHJTLq&var=&widget_ver=artemis&media=COPY

https://www.ebay.de/itm/183926559599?mkcid=16&mkevt=1&mkrid=707-127634-2357-0&sss po=2FGIWbVPRim&sssrc=4429486&ssuid=HIkhxjHJTLq&var=&widget_ver=artemis&media=COPY

https://www.ebay.de/itm/16555629036...IkhxjHJTLq&var=&widget_ver=artemis&media=COPY

https://www.ebay.de/itm/14514060298...IkhxjHJTLq&var=&widget_ver=artemis&media=COPY

https://www.ebay.de/itm/310956395472?mkcid=16&mkevt=1&mkrid=707-127634-2357-0&sss po=EkE56GmhSOi&sssrc=4429486&ssuid=HIkhxjHJTLq&var=&widget_ver=artemis&media=COPY
 
#72
There's no single filter that fits everything!
It always depends on what's connected behind it. A filter for a source device is relatively straightforward, whereas for an amplifier, it's more complicated. I initially used large coils, resulting in a dead, boring sound with dynamic loss. Then I increased the wire diameter of the coils, used lower coil values until I no longer heard any dynamic loss, and then increased the X2 capacitor values until I had almost the same cutoff frequency again (mine was about 1.9 kHz). Try it, and you'll see that every amplifier responds differently to a filter!

You can get reasonable ferrite beads from Thel
 
#78
#79
Honestly, no. I relied exclusively on my multimeter and hearing. I've been doing it this way for about twenty years. A friend of mine once did measurements on one of my line filters. The calculations roughly matched the measurements. The attenuation was about 35 dB at 5 kHz, although asymmetrical interference was somewhat less attenuated; no standardized test method was used.
 
You must log in or register to reply here.
Top Bottom