Line powered audio switch, getting there it seems

O

OBones

Guest
Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.

Cheers
Olivier
 
On Tue, 26 Apr 2005 19:29:39 +0200, in sci.electronics.design OBones
<obones_gfd_@_gds_altern.org> wrote:

Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.

Cheers
Olivier
Nice try, but..................
Click to expand...

OP213 3mA per opamp Iq.

consider the initial startup, no VCC.

Audio in via 100K resistor, how does the opamp rectify without VCC.

6V/100K is not a lot of current.

Keep trying...( I like the page design)



martin

After the first death, there is no other.
(Dylan Thomas)
 
On Tue, 26 Apr 2005 19:29:39 +0200, in sci.electronics.design OBones
<obones_gfd_@_gds_altern.org> wrote:

Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.

Cheers
Olivier
This might be a dead end, but
Click to expand...

follow the transformer bridge rectifier
If (a big IF) you can obtain 20uA you could power a 74HC4052 cmos
switch. (Icc 18uA max)


martin

After the first death, there is no other.
(Dylan Thomas)
 
I read in sci.electronics.design that OBones
<obones_gfd_@_gds_altern.org> wrote (in
<426e7a87$0$5357$636a15ce@news.free.fr>) about 'Line powered audio
switch, getting there it seems', on Tue, 26 Apr 2005:
I would very much appreciate feedback from more experienced designers.
Click to expand...
I don't think it will start, because the op-amp needs Vcc before it will
generate it. You need to take your Vcc directly from the transformer
secondary via a single Schottky diode and filter cap.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
John Woodgate wrote:

I read in sci.electronics.design that OBones
obones_gfd_@_gds_altern.org> wrote (in
426e7a87$0$5357$636a15ce@news.free.fr>) about 'Line powered audio
switch, getting there it seems', on Tue, 26 Apr 2005:

I would very much appreciate feedback from more experienced designers.


I don't think it will start, because the op-amp needs Vcc before it will
generate it. You need to take your Vcc directly from the transformer
secondary via a single Schottky diode and filter cap.
Click to expand...
Yeah, that's what I thought as well. But I think the schema I got for
the op amp rectifier is wrong, there is an almost direct path from the
transformer to the output.

Anyway, if I was to use a single low drop out diode (like BAT42 for
instance), that would do half wave regulation and I guess it would be
enough for my purposes. It would mean longer charge time, but that's no
big deal.
Would that be right?

Cheers
Olivier
 
martin griffith wrote:

On Tue, 26 Apr 2005 19:29:39 +0200, in sci.electronics.design OBones
obones_gfd_@_gds_altern.org> wrote:


Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.

Cheers
Olivier

Nice try, but..................

OP213 3mA per opamp Iq.

consider the initial startup, no VCC.

Audio in via 100K resistor, how does the opamp rectify without VCC.

6V/100K is not a lot of current.

Keep trying...( I like the page design)
Click to expand...
Thanks for the input, I'll keep trying.
As to the page design, I like it too ;-)

Cheers
Olivier
 
I read in sci.electronics.design that OBones
<obones_gfd_@_gds_altern.org> wrote (in
<426ead0e$0$5353$636a15ce@news.free.fr>) about 'Line powered audio
switch, getting there it seems', on Tue, 26 Apr 2005:

Anyway, if I was to use a single low drop out diode (like BAT42 for
instance), that would do half wave regulation and I guess it would be
enough for my purposes. It would mean longer charge time, but that's no
big deal.
Would that be right?
Click to expand...
Yes. First get your Vcc sorted out, then go on to the relay supply
rectifier etc.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
 
On Tue, 26 Apr 2005 23:05:19 +0200, OBones
<obones_gfd_@_gds_altern.org> wrote:

John Woodgate wrote:

I read in sci.electronics.design that OBones
obones_gfd_@_gds_altern.org> wrote (in
426e7a87$0$5357$636a15ce@news.free.fr>) about 'Line powered audio
switch, getting there it seems', on Tue, 26 Apr 2005:

I would very much appreciate feedback from more experienced designers.


I don't think it will start, because the op-amp needs Vcc before it will
generate it. You need to take your Vcc directly from the transformer
secondary via a single Schottky diode and filter cap.

Yeah, that's what I thought as well. But I think the schema I got for
the op amp rectifier is wrong, there is an almost direct path from the
transformer to the output.

Anyway, if I was to use a single low drop out diode (like BAT42 for
instance), that would do half wave regulation and I guess it would be
enough for my purposes. It would mean longer charge time, but that's no
big deal.
Would that be right?

Cheers
Olivier
Click to expand...
Doesn't the relay driver circuitry seem overly complicated? Why is an
H bridge required? The relay has only 2 states, either operated or non
operated. That takes only one transistor and simple toggle logic IMO.
 
On Tue, 26 Apr 2005 22:55:09 +0000, Ross Herbert wrote:
On Tue, 26 Apr 2005 23:05:19 +0200, OBones
John Woodgate wrote:
I read in sci.electronics.design that OBones
I would very much appreciate feedback from more experienced designers.
Anyway, if I was to use a single low drop out diode (like BAT42 for
instance), that would do half wave regulation and I guess it would be
enough for my purposes. It would mean longer charge time, but that's no
big deal.
Would that be right?
Doesn't the relay driver circuitry seem overly complicated? Why is an
H bridge required? The relay has only 2 states, either operated or non
operated. That takes only one transistor and simple toggle logic IMO.
Click to expand...
If he has to push a button anyway, I can't understand why he doesn't just
get a switch:
http://www.allelectronics.com/cgi-bin/category.cgi?item=PB-94

Cheers!
Rich
 
Ross Herbert wrote:

Doesn't the relay driver circuitry seem overly complicated? Why is an
H bridge required? The relay has only 2 states, either operated or non
operated. That takes only one transistor and simple toggle logic IMO.
Click to expand...
This is a latching relay, with one coil. Depending on the current flow
direction, the relay will be set or reset. Hence the need to have a
circuit allowing to control which way the current flows inside the coil,
and the H bridge is the only one I know of.
 
Rich Grise wrote:

If he has to push a button anyway, I can't understand why he doesn't just
get a switch:
http://www.allelectronics.com/cgi-bin/category.cgi?item=PB-94
Click to expand...
As I said on the website, I know those buttons exist, but for the fun of
it I'm investigating an electronics based solution.
 
OBones wrote:

Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.
Click to expand...
You have a basic problem with the law of conservation of energy. ;-)

Graham
 
On Wed, 27 Apr 2005 07:23:12 +0100, in sci.electronics.design Pooh
Bear <rabbitsfriendsandrelations@hotmail.com> wrote:

OBones wrote:

Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.

You have a basic problem with the law of conservation of energy. ;-)

Graham
Nope, it's an Over Unity device, the palladium contacts on the relay
Click to expand...
will.......


martin

After the first death, there is no other.
(Dylan Thomas)
 
Pooh Bear wrote:

OBones wrote:

Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7
http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.


You have a basic problem with the law of conservation of energy. ;-)
Click to expand...
Could you explain a bit more, I'm curious.
 
"OBones" <obones_gfd_@_gds_altern.org> wrote in message
news:426e7a87$0$5357$636a15ce@news.free.fr...
Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.

Cheers
Olivier
Click to expand...
Apart from the other problems already mentioned, you need to have some
contact debounce, when the switch initialy makes contact the contacts bounce
and make and break several times over about 10ms, wich wil togle the flip
flop an inderterminate amount of times, an rc filter folowed by a schmit
triger usualy sufices, or if you have make and break or changover contacts
you can just use a capacitor.

Colin =^.^=
 
colin wrote:

"OBones" <obones_gfd_@_gds_altern.org> wrote in message
news:426e7a87$0$5357$636a15ce@news.free.fr...

Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.

Cheers
Olivier


Apart from the other problems already mentioned, you need to have some
contact debounce, when the switch initialy makes contact the contacts bounce
and make and break several times over about 10ms, wich wil togle the flip
flop an inderterminate amount of times, an rc filter folowed by a schmit
triger usualy sufices, or if you have make and break or changover contacts
you can just use a capacitor.
Click to expand...
Thanks for that.
 
OBones wrote:

Pooh Bear wrote:

OBones wrote:

Hi all

A few days ago, I started a thread to ask if it would be feasible to
create a line powered audio switch connecting one stereo output to
either of two inputs.
After a nice discussion with many people, I came up with a schematic
that is available at this address:

http://obones.com/index.php?module=article&view=7
http://obones.com/index.php?module=article&view=7

Along with it is the detail the working principle, as I understand it.
Could anyone be kind enough to have a look at this and comment on it?
I would very much appreciate feedback from more experienced designers.


You have a basic problem with the law of conservation of energy. ;-)

Could you explain a bit more, I'm curious.
Click to expand...
Basically says - you can't create more energy by use of a device than you had
to begin with. All systems are 'lossy'.

Graham
 
John Woodgate wrote:

Yes. First get your Vcc sorted out, then go on to the relay supply
rectifier etc.
Click to expand...
Okay, I think I've got it sorted, it's online here:

http://obones.com/index.php?module=article&view=7&MMN_position=22:18

It looks like following a trail of clues, but I'd like to eventually get
there.
Thanks to all for the help and support.

Cheers
Olivier
 
"OBones" <obones_gfd_@_gds_altern.org> wrote in message
news:42714c9d$0$26321$626a14ce@news.free.fr...
Okay, I think I've got it sorted, it's online here:

http://obones.com/index.php?module=article&view=7&MMN_position=22:18

It looks like following a trail of clues, but I'd like to eventually get
there.
Thanks to all for the help and support.
Click to expand...
The OP213 still draw 3 mA/amplifier. That corresponds to a 6 V drop across
R4...

I don't think the opamp full-wave rectifier works like you think it does; it
will never output a voltage greater than Vcc, and is therefore not helping
anything. You can get rid of it.

Would a lithium battery be considered unsporting?

Jonathan
http://cq.cx/
 
Jonathan Westhues wrote:

The OP213 still draw 3 mA/amplifier. That corresponds to a 6 V drop across
R4...
Click to expand...
OP213 is just a reference for an op amp, I can find a better one with
respect to consumption.


I don't think the opamp full-wave rectifier works like you think it does; it
will never output a voltage greater than Vcc, and is therefore not helping
anything. You can get rid of it.
Click to expand...
Ok, but what to use instead ? A single BAT-42 diode just like for the
Vcc storage ? Or a bridge made out of low forward voltage diodes ?
I went the "op amp" way as someone suggested that diodes would not
behave properly with low voltages like that.


Would a lithium battery be considered unsporting?
Click to expand...
Yeah, it would ;-)
After all, I know I could use a mechanical switch just to do all this.

Thanks for the help.
 
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