Filter RF interference from mobile phones - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 2nd October 2008, 06:39 PM   #1
diyAudio Member
Join Date: Feb 2007
Location: Algarve
Default Filter RF interference from mobile phones


So, I had to get myself a Vodafone Connect Pen (mobile broadband), as I'm studying and living there most of the time. The problem is: I am going to take one of my amps (the TDA clone), and a small pair of speakers, to have music, and the vodafone card, just like any GSM phone, is causing audible interference, that we all know so well...
In my LM3886 I don't have the problem.
So, I'd like to hear some hints on what can I do to filter that.
I am thinking of:

- putting a 330pF cap between -In and +In of the chipamps, and also the preamp section opamps.
- putting 10pF decoupling caps at +V and -V to gnd, at both chipamps, and maybe also the preamp opamps?
- "glueing" some aluminium foil at the insides of the case, that are free (unfortunately very few... as most electronic is mounted there), as the case is wooden...
- installing ferrite beads (those found, i.e, in usb cables) around the cables that go from chipamp output to speaker binding posts.
- I already have a simple LPF at the amp's inputs, in form of 100pF to GND. Should I add another cap to the input of the preamp section opamps, aswell?

Any further ideas?

P.S.: interference isn't coming from input wires:
I can pull them out, and regulate volume pot to 0%, and still hear the same mobile phone buzzes...
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
how much DC through phones is okay? cuibono Everything Else 2 20th April 2008 12:22 AM
Toroidal transformer bolt question & mobile phone interference markiemrboo Chip Amps 19 5th December 2006 11:15 PM
CDMA tri-mode phones purplepeople Everything Else 10 1st October 2004 10:12 PM

New To Site? Need Help?

All times are GMT. The time now is 11:59 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2