SV VCF vs wireless lan and cordless telephone

isak

Hi guys.

i finished the SV VCF 12db from MFOS few days ago.
turn it up i was very happy to hear its sounds amazing.
but...(there is always but) i heard background noises, not like any hiss or white noise or any thing like it.
i actually heard bipping sound and some f**** low freq osc sound with it.
i was very mad that i was not able to find the problem and sent an email to Ray.
he was so kind and was trying to help but without any success.
i did everything i thought i needed to do to try fixing this noises, replaced chips replaced transistors and so on...
and then i thought to my self that thous sounds sound like air interference, i turn off the wireless lan (sits on my soldering working desk) soddenly the low freq osc sound is gone, and the bipping sound is still on, i turn off the cordless telephone i have also on the soldering desk and the sound went off and i could hear only the natural white noise of this amazing SV VCF.

now for the question...
HOW THE HELL I GET RID OF IT?

BTW the wireless lan is : TP-Link, model : TLWR340G
the cordless telephone is : Uniden apx7000
PS i cant move them from the room, cable issues and stuff..

cheers,
Isak E.

marvkaye · Joined: Mar 14, 2011 Posts: 221 Location: Fla

A lot of designers incorporate ferrite beads into the power lines on their PCBs to filter stray noise caused by RF sources, which is what it sounds like you're dealing with... maybe adding them to your power inputs will help. They simply get installed in series with the + and - leads right where they come into your PCB. It's worth a shot.

<marv>

isak · Posted: Fri May 25, 2012 10:43 pm Post subject:

Hi Marv and thank you for replying.

Adding them? Sorry, I don't understand.
What do you mean?
Can you explaine please what exactly I need to try?

Thanks in advance,
Isak E.

marvkaye · Joined: Mar 14, 2011 Posts: 221 Location: Fla

The ferrites look like resistors, just small black cylinders with axial leads. To connect them in series with the power leads you need to disconnect the +12 and -12 wires from the PCB. You would connect the +12 lead from your power supply to one end of a ferrite and connect the other end of the ferrite to the +12 pad on the PCB. Run a piece of shrink tubing up the wire before doing the connection so you can shrink it over the ferrite and its leads when the mod is completed. Do the same thing with the -12 wire and you're done.

isak · Posted: Sat May 26, 2012 12:14 pm Post subject:

Hi Marv.

i dont know what is "ferrite".
its the first time i hear about it Embarassed

.

where can i get this ferrite?

elmegil · Posted: Sat May 26, 2012 1:40 pm Post subject:

The ones pictured are on a larger scale than we're talking about but here's some background:

http://en.wikipedia.org/wiki/Ferrite_bead

isak · Posted: Sat May 26, 2012 3:09 pm Post subject:

Thanks for the link.

Seems that I know what it is after see the link above.
I just didn't knew its called ferrite.

Thank again,
Isak E.

marvkaye · Joined: Mar 14, 2011 Posts: 221 Location: Fla

Look up Mouser part #623-2743001112LF then follow the link to the catalog page to see what they look like. They're in the 2nd box up from the bottom on the right hand side of the page, labeled EMI SHIELD BEADS ON LEADS. I hope this helps.

<marv>

isak · Posted: Sat May 26, 2012 9:35 pm Post subject:

Thank you very much!

isak · Posted: Mon Jun 04, 2012 1:23 am Post subject:

Hi guys.

just got the ferrites beads, gonna test them tonight, cross my fingers Shocked

.

i'll update as soon as i'll finish.

cheers,
Isak E.

isak · Posted: Mon Jun 04, 2012 9:27 pm Post subject:

Hi guys.

Sadly...didnt worked, not even a bit.

Any more ideas?

kvitekp · Joined: Feb 24, 2012 Posts: 22 Location: Santa Clara, CA

You may want to try different WiFi router: I have two antenna D-Link router sitting across the wall from my modular (distance is about 5 to 6 feet) and there is no interference.

However, my neighbor across the street is ham radio enthusiast, his house roof is full of antennas. I often see and hear his interference when working with prototyping boards, it's easy to detect since he usually is active at certain time.

Ferrite beads on each module power inputs, tightly twisted pairs on all control signals and shielded cable on all audio signals help to defeat EMI interference.

Also, make sure your power supply provides adequate filtering of AC lines high frequency noise.

/Peter

isak · Posted: Sat Jun 16, 2012 11:42 pm Post subject:

Thank you Peter.

Do you think that the ferrites beads need to be on the pcb audio signal out or at the audio out jacks or on both pcb and jacks?
What about the input, do I need to put them there as well?