Switching audio signals with relay - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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
Reply
 
Thread Tools Search this Thread
Old 15th April 2004, 04:36 PM   #1
diyAudio Member
 
Join Date: Apr 2004
Location: Cleveland, OH
Unhappy Switching audio signals with relay

Hey all,
I'm new and am not sure which section to post this in, but does anyone know how to switch audio signals with a relay without getting noise in the speakers? I know I need some sort of "filter" circuit, but I have no idea how to make one...any help would be appreciated.

Thanks,
Niral
  Reply With Quote
Old 15th April 2004, 06:54 PM   #2
gmarsh is offline gmarsh  Canada
diyAudio Member
 
gmarsh's Avatar
 
Join Date: Apr 2004
Location: Halifax, NS, Canada
Make sure the signals you're switching are muted, and have no DC offset, and you'll be OK.
  Reply With Quote
Old 15th April 2004, 08:12 PM   #3
diyAudio Member
 
Jan Dupont's Avatar
 
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
And make sure that your relay's will make a "Break before connection", so you avoid paralleling the two speakers
__________________
Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com
  Reply With Quote
Old 15th April 2004, 08:22 PM   #4
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
niral622, what sort of signals do you plan to switch? Is it input signals, speaker outputs?

It's rather important that the di/dt for the relays are reduced meaning that the switch off should be slow downed. If you only have a freewheeling diode across the relay coil you will get switch-off transients (0.7 volt over the supply voltage) from the diodes. This rather small but fast flank may cause capacitive or inductive coupling causing clicks. You can avoid this simply by making the switch-off slow but not too slow, just enough to avoid this click.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 16th April 2004, 02:48 AM   #5
diyAudio Member
 
Join Date: Apr 2004
Location: Cleveland, OH
Quote:
what sort of signals do you plan to switch? Is it input signals, speaker outputs?
I was planning on switching inputs between a CD player output and Computer sound card output
  Reply With Quote
Old 17th April 2004, 09:05 PM   #6
diyAudio Member
 
Join Date: Jan 2004
Location: rouen
Send a message via ICQ to apolon34
hi,

i just use small signal relays from naďs with no particular circuitry. they are polarised so i don't need for protection diode.

no noise or 'click' at all.
  Reply With Quote
Old 17th April 2004, 09:56 PM   #7
johnnyx is offline johnnyx  United Kingdom
diyAudio Member
 
Join Date: Jan 2004
Location: manchester
Default Relay Sigal Switching

Use gold plated cotact relays specified for low level switching, these relays have a minimum current of say 10uA.
If silver cotacts are used, they will become noisy and fail after time, the arcing when they switch cleans off the tarnish on the contact faces, and this will not occur with a CD player etc. output.
Telecomms. spec. relays should be used. I used "Type 47" relays in a preamp, with good results. I have also used reed relays.
Polarised relays still need a diode; they are polarised with a magnet to reduce the switching current in the coil, increasing sensitivity.
  Reply With Quote
Old 17th April 2004, 10:03 PM   #8
Banned
 
Join Date: Apr 2002
Location: Germany, Clausthal
I use Takamisawa RY12W-K and just recived a bunch of Meisei M1B-12H. Both are also used in commercial audio equipment.
  Reply With Quote
Old 18th April 2004, 06:14 AM   #9
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
Quote:
Originally posted by apolon34
hi,

i just use small signal relays from naďs with no particular circuitry. they are polarised so i don't need for protection diode.

no noise or 'click' at all.
Indeed, you need freewheeling diodes! Polarized means that the relay has a small permanent magnet inside which helps a bit to activate the relay (=less power consumption). If you use transistors as switching elements these diodes are essential but if you have a mechanical switch it's not that important but I recommend you to use these diodes because it will save the switch.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 18th April 2004, 09:45 AM   #10
diyAudio Member
 
Join Date: Jan 2004
Location: rouen
Send a message via ICQ to apolon34
I use bc547b in commutation to activate it.

it's running well six at least six months.

i'll add protection diode, just in case of...

thanks for the tip
  Reply With Quote

Reply


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
need dpdt switching relay help subaruzero Parts 1 27th September 2006 07:27 PM
help cleaning up switching signals please Evan Shultz Class D 5 2nd November 2005 03:12 PM
Solid state switching of signals eeka chu Parts 4 31st July 2005 10:59 AM
Relay switching circuit please jnewbold Solid State 10 3rd March 2005 06:39 AM
AV amp switching relay TPC Solid State 1 20th April 2003 05:00 PM


New To Site? Need Help?

All times are GMT. The time now is 04:10 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2