Speaker switch

smithy666 · 6th August 2008, 11:36 PM

I'm just starting to design an A/B speaker switch, that will use a small 8 pin PIC (12F675) and a couple of latching relays, operated by any style of momentary push button switch. It will also provide LED indication of which speaker is selected. I will design a couple of PCBs to suit. Just testing to see if there would be any interest in this project - if so I will get a few more PCBs made at the time.

Jan Dupont · 7th August 2008, 06:04 AM

Please provide some details like power handling, and how to get PIC source code etc.

smithy666 · 7th August 2008, 06:31 AM

I'm still looking at options for the relays, but would be min 8A switching rating. Going for latching does seem to limit the options available (at least for high quality sealed), and I prefer to use latching in this operation. I was thinking about paralleling 2, but I've gone off this due to concerns if 1 relay fails and doesn't switch over. Although I guess you would notice this (both speakers playing), so maybe it isn't such a big deal and it might be better power handling/quality wise to parallel two. Your thoughts?

Happy to make the source code freely available - there's no rocket science in it - so you can change it as you see fit (eg I'm making it light up 1 or 2 LEDs depending upon which speaker is selected)

Jan Dupont · 7th August 2008, 06:40 AM

Why latching relays ? You really narrow your choices....
If you want to make something easy to build, go for standard relays (consumption is only 30-40 mA at 24 Volts).
If you go for e.g. FINDER Series 4061 (16A) relays, the special Amplimo (20/100A) speaker relay fit´s in.
www.amplimo.nl

smithy666 · 7th August 2008, 06:50 AM

I really wanted to have next to zero power consumption (as these are never turned off) and having 4 relays potentially "on" all the time would be using a constant 4W. I know, it's not much but I would prefer if it was 0.1W (PIC power draw only)

Jan Dupont · 7th August 2008, 06:52 AM

Do you want two sets of speakers (two relays) connected "activated" at the same time

Edited

smithy666 · 7th August 2008, 06:56 AM

No but I would use one relay for the +ve, one for ground for each channel - sorry I wasn't clear

Jan Dupont · 7th August 2008, 06:57 AM

Why one for ground

smithy666 · 7th August 2008, 07:29 AM

I prefer to switch all connections. Just a personal preference. Likewise with preamp input switching.

Jan Dupont · 7th August 2008, 07:49 AM

That's ok

I agree regarding preamp input switching to prevent crosstalk between inputs, but for speaker outputs I don't see the point....
However good luck with the project

6th August 2008, 11:36 PM	#1
smithy666 diyAudio Member Join Date: Mar 2001 Location: Sydney	Speaker switch I'm just starting to design an A/B speaker switch, that will use a small 8 pin PIC (12F675) and a couple of latching relays, operated by any style of momentary push button switch. It will also provide LED indication of which speaker is selected. I will design a couple of PCBs to suit. Just testing to see if there would be any interest in this project - if so I will get a few more PCBs made at the time.

7th August 2008, 06:04 AM	#2
Jan Dupont diyAudio Member Join Date: Apr 2003 Location: Copenhagen, Denmark	Please provide some details like power handling, and how to get PIC source code etc. __________________ Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com

7th August 2008, 06:40 AM	#4
Jan Dupont diyAudio Member Join Date: Apr 2003 Location: Copenhagen, Denmark	Why latching relays ? You really narrow your choices.... If you want to make something easy to build, go for standard relays (consumption is only 30-40 mA at 24 Volts). If you go for e.g. FINDER Series 4061 (16A) relays, the special Amplimo (20/100A) speaker relay fit´s in. www.amplimo.nl __________________ Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com

7th August 2008, 06:52 AM	#6
Jan Dupont diyAudio Member Join Date: Apr 2003 Location: Copenhagen, Denmark	Do you want two sets of speakers (two relays) connected "activated" at the same time Edited __________________ Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com

7th August 2008, 06:57 AM	#8
Jan Dupont diyAudio Member Join Date: Apr 2003 Location: Copenhagen, Denmark	Why one for ground __________________ Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com


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7th August 2008, 06:31 AM	#3
smithy666 diyAudio Member Join Date: Mar 2001 Location: Sydney	I'm still looking at options for the relays, but would be min 8A switching rating. Going for latching does seem to limit the options available (at least for high quality sealed), and I prefer to use latching in this operation. I was thinking about paralleling 2, but I've gone off this due to concerns if 1 relay fails and doesn't switch over. Although I guess you would notice this (both speakers playing), so maybe it isn't such a big deal and it might be better power handling/quality wise to parallel two. Your thoughts? Happy to make the source code freely available - there's no rocket science in it - so you can change it as you see fit (eg I'm making it light up 1 or 2 LEDs depending upon which speaker is selected)

7th August 2008, 06:50 AM	#5
smithy666 diyAudio Member Join Date: Mar 2001 Location: Sydney	I really wanted to have next to zero power consumption (as these are never turned off) and having 4 relays potentially "on" all the time would be using a constant 4W. I know, it's not much but I would prefer if it was 0.1W (PIC power draw only)

7th August 2008, 06:56 AM	#7
smithy666 diyAudio Member Join Date: Mar 2001 Location: Sydney	No but I would use one relay for the +ve, one for ground for each channel - sorry I wasn't clear

7th August 2008, 07:29 AM	#9
smithy666 diyAudio Member Join Date: Mar 2001 Location: Sydney	I prefer to switch all connections. Just a personal preference. Likewise with preamp input switching.

7th August 2008, 07:49 AM	#10
Jan Dupont diyAudio Member Join Date: Apr 2003 Location: Copenhagen, Denmark	That's ok I agree regarding preamp input switching to prevent crosstalk between inputs, but for speaker outputs I don't see the point.... However good luck with the project __________________ Free Schematic and Service Manual downloads www.audio-circuit.dk, Company: www.dupont-audio.com, Joint venture: www.DupontMantra.com

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