Electronically switching an audio signal

[webpaul]

I'm trying to create an electronic switch so that I can turn on and
off an audio signal using an on/off signal of +3V/0V. For my test rig
I have a mono plug from a music source with two wires exposed, a red
and black. To start simple I first connect the red wire from the mono
plug to the red wire of an 8 ohm speaker and the black wire from the
speaker to the black of the mono plug - and I hear the music,
everything works fine. Now if I put a SPST switch between either of
those lines I have a mechanical version of what I want.

I've been struggling getting an electronic version working though.
I've been trying multiple things similar to what is shown at the below
link at the bottom of the page, using a transistor to try and do the
switching:

http://www.pic101.com/understanding_single_line_ptt.htm

I am a little confused what to do in this scenario with the black
wires, i've tried multiple arrangements and haven't been able to get
it to work. I've also tried feeding the audio and the +3/0V signal
through an AND gate but that didn't work either. What I would like to
be able to do is take +3V and apply it to a wire and have the audio
come on and when the wire is removed the audio will stop playing.
Seems simple but I haven't been able to figure it out. I'd like to
start with simple and possibly dangerous because of shared ground or
having a hum and then build on that with an octocoupler or something
similar to make it nicer. But first things first, how do I get the
simple circuit working with (I'm assuming) a transistor? I'd rather
not use a relay to avoid clicking sounds as it switches and because I
don't have any currently.

 

[George Herold]

On Feb 3, 1:00 am, webpaul <pb648...@gmail.com> wrote:

I'm trying to create an electronic switch so that I can turn on and
off an audio signal using an on/off signal of +3V/0V. For my test rig
I have a mono plug from a music source with two wires exposed, a red
and black. To start simple I first connect the red wire from the mono
plug to the red wire of an 8 ohm speaker and the black wire from the
speaker to the black of the mono plug - and I hear the music,
everything works fine. Now if I put a SPST switch between either of
those lines I have a mechanical version of what I want.

I've been struggling getting an electronic version working though.
I've been trying multiple things similar to what is shown at the below
link at the bottom of the page, using a transistor to try and do the
switching:

http://www.pic101.com/understanding_single_line_ptt.htm

I am a little confused what to do in this scenario with the black
wires, i've tried multiple arrangements and haven't been able to get
it to work. I've also tried feeding the audio and the +3/0V signal
through an AND gate but that didn't work either. What I would like to
be able to do is take +3V and apply it to a wire and have the audio
come on and when the wire is removed the audio will stop playing.
Seems simple but I haven't been able to figure it out. I'd like to
start with simple and possibly dangerous because of shared ground or
having a hum and then build on that with an octocoupler or something
similar to make it nicer. But first things first, how do I get the
simple circuit working with (I'm assuming) a transistor? I'd rather
not use a relay to avoid clicking sounds as it switches and because I
don't have any currently.

A relay may be what you want. Though the 3 volts may be a little low.
There are also analog switches, though I don't think you want to put
the output from a stero through one...

George H.

 

[webpaul]

Got it working using a relay, would love to see a non relay example
based on what I have to get rid of the clicking sound. Here is a
picture of what I have, feel free to offer suggestions or alternate
schematics to replace the relay without introducing any additional
constraints such as more power or a negative power supply source.

On Feb 3, 10:40 am, George Herold <ggher...@gmail.com> wrote:

On Feb 3, 1:00 am, webpaul <pb648...@gmail.com> wrote:





I'm trying to create an electronic switch so that I can turn on and
off an audio signal using an on/off signal of +3V/0V. For my test rig
I have a mono plug from a music source with two wires exposed, a red
and black. To start simple I first connect the red wire from the mono
plug to the red wire of an 8 ohm speaker and the black wire from the
speaker to the black of the mono plug - and I hear the music,
everything works fine. Now if I put a SPST switch between either of
those lines I have a mechanical version of what I want.

I've been struggling getting an electronic version working though.
I've been trying multiple things similar to what is shown at the below
link at the bottom of the page, using a transistor to try and do the
switching:

http://www.pic101.com/understanding_single_line_ptt.htm

I am a little confused what to do in this scenario with the black
wires, i've tried multiple arrangements and haven't been able to get
it to work. I've also tried feeding the audio and the +3/0V signal
through an AND gate but that didn't work either. What I would like to
be able to do is take +3V and apply it to a wire and have the audio
come on and when the wire is removed the audio will stop playing.
Seems simple but I haven't been able to figure it out. I'd like to
start with simple and possibly dangerous because of shared ground or
having a hum and then build on that with an octocoupler or something
similar to make it nicer. But first things first, how do I get the
simple circuit working with (I'm assuming) a transistor? I'd rather
not use a relay to avoid clicking sounds as it switches and because I
don't have any currently.

A relay may be what you want.  Though the 3 volts may be a little low.
There are also analog switches, though I don't think you want to put
the output from a stero through one...

George H.- Hide quoted text -

- Show quoted text -

 

[webpaul]

Whoops, here is the picture:

http://i1200.photobucket.com/albums/bb335/pb648174/IMG_1276.jpg


On Feb 4, 9:58 pm, webpaul <pb648...@gmail.com> wrote:

Got it working using a relay, would love to see a non relay example
based on what I have to get rid of the clicking sound. Here is a
picture of what I have, feel free to offer suggestions or alternate
schematics to replace the relay without introducing any additional
constraints such as more power or a negative power supply source.

On Feb 3, 10:40 am, George Herold <ggher...@gmail.com> wrote:



On Feb 3, 1:00 am, webpaul <pb648...@gmail.com> wrote:

I'm trying to create an electronic switch so that I can turn on and
off an audio signal using an on/off signal of +3V/0V. For my test rig
I have a mono plug from a music source with two wires exposed, a red
and black. To start simple I first connect the red wire from the mono
plug to the red wire of an 8 ohm speaker and the black wire from the
speaker to the black of the mono plug - and I hear the music,
everything works fine. Now if I put a SPST switch between either of
those lines I have a mechanical version of what I want.

I've been struggling getting an electronic version working though.
I've been trying multiple things similar to what is shown at the below
link at the bottom of the page, using a transistor to try and do the
switching:

http://www.pic101.com/understanding_single_line_ptt.htm

I am a little confused what to do in this scenario with the black
wires, i've tried multiple arrangements and haven't been able to get
it to work. I've also tried feeding the audio and the +3/0V signal
through an AND gate but that didn't work either. What I would like to
be able to do is take +3V and apply it to a wire and have the audio
come on and when the wire is removed the audio will stop playing.
Seems simple but I haven't been able to figure it out. I'd like to
start with simple and possibly dangerous because of shared ground or
having a hum and then build on that with an octocoupler or something
similar to make it nicer. But first things first, how do I get the
simple circuit working with (I'm assuming) a transistor? I'd rather
not use a relay to avoid clicking sounds as it switches and because I
don't have any currently.

A relay may be what you want.  Though the 3 volts may be a little low..
There are also analog switches, though I don't think you want to put
the output from a stero through one...

George H.- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

 

[George Herold]

On Feb 4, 10:58 pm, webpaul <pb648...@gmail.com> wrote:

Whoops, here is the picture:

http://i1200.photobucket.com/albums/bb335/pb648174/IMG_1276.jpg

On Feb 4, 9:58 pm, webpaul <pb648...@gmail.com> wrote:



Got it working using a relay, would love to see a non relay example
based on what I have to get rid of the clicking sound. Here is a
picture of what I have, feel free to offer suggestions or alternate
schematics to replace the relay without introducing any additional
constraints such as more power or a negative power supply source.

On Feb 3, 10:40 am, George Herold <ggher...@gmail.com> wrote:

On Feb 3, 1:00 am, webpaul <pb648...@gmail.com> wrote:

I'm trying to create an electronic switch so that I can turn on and
off an audio signal using an on/off signal of +3V/0V. For my test rig
I have a mono plug from a music source with two wires exposed, a red
and black. To start simple I first connect the red wire from the mono
plug to the red wire of an 8 ohm speaker and the black wire from the
speaker to the black of the mono plug - and I hear the music,
everything works fine. Now if I put a SPST switch between either of
those lines I have a mechanical version of what I want.

I've been struggling getting an electronic version working though.
I've been trying multiple things similar to what is shown at the below
link at the bottom of the page, using a transistor to try and do the
switching:

http://www.pic101.com/understanding_single_line_ptt.htm

I am a little confused what to do in this scenario with the black
wires, i've tried multiple arrangements and haven't been able to get
it to work. I've also tried feeding the audio and the +3/0V signal
through an AND gate but that didn't work either. What I would like to
be able to do is take +3V and apply it to a wire and have the audio
come on and when the wire is removed the audio will stop playing.
Seems simple but I haven't been able to figure it out. I'd like to
start with simple and possibly dangerous because of shared ground or
having a hum and then build on that with an octocoupler or something
similar to make it nicer. But first things first, how do I get the
simple circuit working with (I'm assuming) a transistor? I'd rather
not use a relay to avoid clicking sounds as it switches and because I
don't have any currently.

A relay may be what you want.  Though the 3 volts may be a little low.
There are also analog switches, though I don't think you want to put
the output from a stero through one...

George H.- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

There are lots of analog switches out there.... I found the ADG702 as
the first hit on a digikey search... This will only handle 30mA. How
much current are you switching? (Digikey is great for parameter
searches)

I haven't used an analog switch in several years... perhaps someone
else will have some other part numbers to try.

George H.