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Ping Paul - silly question - intelligent answer please.



 
 
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  #1  
Old September 26th 19, 06:05 PM posted to alt.comp.hardware.pc-homebuilt
Shadow[_2_]
external usenet poster
 
Posts: 190
Default Ping Paul - silly question - intelligent answer please.


I have an old MP3 Player, one that uses a single AAA battery and plays
for at least 4-5 hours with a recharged battery. Using Philips
ear-buds, which are uncomfortable ...
I have some reasonably good quality Philips Headphones, which I use on
the PC.
What would happen if I plug the headphone into the MP3 player? Damage
it? Drain the batteries in 20 minutes? Overheat? No sound audible?

I tried Googling, but all I got was ads ....

PS My physics is schoolboy stuff learned 40 years ago. I remember
vaguely that V=RI and P=voltage squared/R. But that's about it.
TIA
[]'s
--
Don't be evil - Google 2004
We have a new policy - Google 2012
  #2  
Old September 26th 19, 08:33 PM posted to alt.comp.hardware.pc-homebuilt
Paul[_28_]
external usenet poster
 
Posts: 1,146
Default Ping Paul - silly question - intelligent answer please.

Shadow wrote:
I have an old MP3 Player, one that uses a single AAA battery and plays
for at least 4-5 hours with a recharged battery. Using Philips
ear-buds, which are uncomfortable ...
I have some reasonably good quality Philips Headphones, which I use on
the PC.
What would happen if I plug the headphone into the MP3 player? Damage
it? Drain the batteries in 20 minutes? Overheat? No sound audible?

I tried Googling, but all I got was ads ....

PS My physics is schoolboy stuff learned 40 years ago. I remember
vaguely that V=RI and P=voltage squared/R. But that's about it.
TIA
[]'s


This depends on the operating characteristics of the
"ear-buds" versus the "headphones".

These are at first appearance, a pretty light load, but they
represent a pretty large capacitance (0.015uF). You would not
expect the power draw to be that high. I used to use these,
and even had some connected to a crystal radio (1N34A germanium
diode, 50 foot horizontal antenna, tuning coil and so on).

http://catalog.miniscience.com/catal.../Earphone.html

1. Impedance: 20K ohm
2. Capacity: 15,000 pf
3. Sensitivity: 57 dB at 1KHz
4. Frequency Range: 200 ~ 8000 Hz
5. Operation Temperatu -20 to 60 Celsius
6. Cord: 3ft twisted cable.

That web page also says:

"A sensitive earphone built around an electromagnet
might have an impedance of about 2,000 ohms"

Well, headphones have tended to settle on a standard
of 32 ohms, which is more electrical load and for
the same voltage level, uses a bit more power. If the
output voltage is around 1V from the MP3 player, then
V^2/R gives 31mW per ear.

In the article here, they claim

https://www.shure.com/en-GB/support/...specifications

"Earphones and headphones range from 8 Ohms to 600 Ohms
or higher. The audio source (the headphone output) also
has an impedance rating. To obtain maximum power transfer
(all usable power from the source reaches the earphones)
impedances should match. However, that's rarely the case."

And we hardly ever worry about the "matching" part and the
"loss" part. Instead, we might worry about "overloading"
the output.

And the MP3 player is probably designed for a 32 ohm load,
which is what we might expect in a 1/8" output jack ecosystem
with 1VRMS output voltage to be expected.

I don't think you're going to kill the device, unless
it states on the output "only for usage with an amplifying
device".

I think I may have had a telecom headset at one time,
and that was around 600 ohms and the ear pieces were
wound with many turns of fine wire (probably #36 to #40
or so). That would be an example of a high impedance
electromagnetic design. But the headphones I have
now are 32 ohms, and would not be nearly the same
construction.

I think it's a safe guess the battery life will be
shorter. I don't think it will kill your MP3 player.
If the MP3 player was "bundled" with earbuds or the
earbuds were permanently affixed to the player, that
would imply something about the adequacy of the design.
(Only designed to work with particular earbuds.)

But if you've ever worked with these, they're amazing.
They're very good on power consumption. My crystal radio
used to give room filling sound, just with the levels
coming out of the earphones lying on the table. No amplifier
or battery source or anything. Just energy picked out
of the air, rectified and presented to the phones. Strictly speaking,
you have to know the output device can drive a load
like this, which is mostly capacitive. The 741 OpAmp
might not like a load like this, and you'd have to put
a 50 ohm resistor into the output to change the pole
a load like this causes.

http://catalog.miniscience.com/catal.../Earphone.html

I think it's safe to try, unless the instructions for
the device specifically limit the kinds of loads it
will accept. There are electronics with 600 ohm output
impedance, and if you plug in a 32 ohm load to those,
there's almost no signal to listen to.

The MP3 player is unlikely to drive 2 ohm, 4 ohm, or
8 ohm speakers, and those could damage it (depending
on whether it's impedance protected or not).

Paul
  #3  
Old September 27th 19, 03:33 AM posted to alt.comp.hardware.pc-homebuilt
Shadow[_2_]
external usenet poster
 
Posts: 190
Default Ping Paul - silly question - intelligent answer please.

On Thu, 26 Sep 2019 15:33:12 -0400, Paul
wrote:

Shadow wrote:
I have an old MP3 Player, one that uses a single AAA battery and plays
for at least 4-5 hours with a recharged battery. Using Philips
ear-buds, which are uncomfortable ...
I have some reasonably good quality Philips Headphones, which I use on
the PC.
What would happen if I plug the headphone into the MP3 player? Damage
it? Drain the batteries in 20 minutes? Overheat? No sound audible?

I tried Googling, but all I got was ads ....

PS My physics is schoolboy stuff learned 40 years ago. I remember
vaguely that V=RI and P=voltage squared/R. But that's about it.
TIA
[]'s


This depends on the operating characteristics of the
"ear-buds" versus the "headphones".

These are at first appearance, a pretty light load, but they
represent a pretty large capacitance (0.015uF). You would not
expect the power draw to be that high. I used to use these,
and even had some connected to a crystal radio (1N34A germanium
diode, 50 foot horizontal antenna, tuning coil and so on).

http://catalog.miniscience.com/catal.../Earphone.html

1. Impedance: 20K ohm
2. Capacity: 15,000 pf
3. Sensitivity: 57 dB at 1KHz
4. Frequency Range: 200 ~ 8000 Hz
5. Operation Temperatu -20 to 60 Celsius
6. Cord: 3ft twisted cable.

That web page also says:

"A sensitive earphone built around an electromagnet
might have an impedance of about 2,000 ohms"

Well, headphones have tended to settle on a standard
of 32 ohms, which is more electrical load and for
the same voltage level, uses a bit more power. If the
output voltage is around 1V from the MP3 player, then
V^2/R gives 31mW per ear.

In the article here, they claim

https://www.shure.com/en-GB/support/...specifications

"Earphones and headphones range from 8 Ohms to 600 Ohms
or higher. The audio source (the headphone output) also
has an impedance rating. To obtain maximum power transfer
(all usable power from the source reaches the earphones)
impedances should match. However, that's rarely the case."

And we hardly ever worry about the "matching" part and the
"loss" part. Instead, we might worry about "overloading"
the output.

And the MP3 player is probably designed for a 32 ohm load,
which is what we might expect in a 1/8" output jack ecosystem
with 1VRMS output voltage to be expected.

I don't think you're going to kill the device, unless
it states on the output "only for usage with an amplifying
device".

I think I may have had a telecom headset at one time,
and that was around 600 ohms and the ear pieces were
wound with many turns of fine wire (probably #36 to #40
or so). That would be an example of a high impedance
electromagnetic design. But the headphones I have
now are 32 ohms, and would not be nearly the same
construction.

I think it's a safe guess the battery life will be
shorter. I don't think it will kill your MP3 player.
If the MP3 player was "bundled" with earbuds or the
earbuds were permanently affixed to the player, that
would imply something about the adequacy of the design.
(Only designed to work with particular earbuds.)

But if you've ever worked with these, they're amazing.
They're very good on power consumption. My crystal radio
used to give room filling sound, just with the levels
coming out of the earphones lying on the table. No amplifier
or battery source or anything. Just energy picked out
of the air, rectified and presented to the phones. Strictly speaking,
you have to know the output device can drive a load
like this, which is mostly capacitive. The 741 OpAmp
might not like a load like this, and you'd have to put
a 50 ohm resistor into the output to change the pole
a load like this causes.

http://catalog.miniscience.com/catal.../Earphone.html

I think it's safe to try, unless the instructions for
the device specifically limit the kinds of loads it
will accept. There are electronics with 600 ohm output
impedance, and if you plug in a 32 ohm load to those,
there's almost no signal to listen to.

The MP3 player is unlikely to drive 2 ohm, 4 ohm, or
8 ohm speakers, and those could damage it (depending
on whether it's impedance protected or not).

Paul


I don't have the specs for the MP3Player, it's pretty old.

The earbuds:

https://www.philips.co.in/c-p/SHE135...specifications

The Headphones:

https://www.usa.philips.com/c-p/SHL3...and-headphones

(Not my exact model, but near enough)

I tried it. Didn't break anything, but I had to turn the
volume up 3 notches to get same volume.

Note Maximum power input 50mW vs 1000mW
Impedance 32 Ohms vs 24 Ohms
I have no idea what that means.

-------------------------
PS I also had a crystal radio, made from a germanium diode, a
variable capacitor (all scrounged from discarded radios) and a very
long wire as an antenna. And a coil, which I made myself and "crystal
earplugs" (those I had to buy).
Kind of scary that radio waves back in the day had enough
energy to vibrate your eardrums from 50 miles away .... I wonder what
they do now with all this 5G hype? Probably vibrate your DNA ....
[]'s





--
Don't be evil - Google 2004
We have a new policy - Google 2012
  #4  
Old September 27th 19, 05:09 AM posted to alt.comp.hardware.pc-homebuilt
Paul[_28_]
external usenet poster
 
Posts: 1,146
Default Ping Paul - silly question - intelligent answer please.

Shadow wrote:
On Thu, 26 Sep 2019 15:33:12 -0400, Paul
wrote:

Shadow wrote:
I have an old MP3 Player, one that uses a single AAA battery and plays
for at least 4-5 hours with a recharged battery. Using Philips
ear-buds, which are uncomfortable ...
I have some reasonably good quality Philips Headphones, which I use on
the PC.
What would happen if I plug the headphone into the MP3 player? Damage
it? Drain the batteries in 20 minutes? Overheat? No sound audible?

I tried Googling, but all I got was ads ....

PS My physics is schoolboy stuff learned 40 years ago. I remember
vaguely that V=RI and P=voltage squared/R. But that's about it.
TIA
[]'s

This depends on the operating characteristics of the
"ear-buds" versus the "headphones".

These are at first appearance, a pretty light load, but they
represent a pretty large capacitance (0.015uF). You would not
expect the power draw to be that high. I used to use these,
and even had some connected to a crystal radio (1N34A germanium
diode, 50 foot horizontal antenna, tuning coil and so on).

http://catalog.miniscience.com/catal.../Earphone.html

1. Impedance: 20K ohm
2. Capacity: 15,000 pf
3. Sensitivity: 57 dB at 1KHz
4. Frequency Range: 200 ~ 8000 Hz
5. Operation Temperatu -20 to 60 Celsius
6. Cord: 3ft twisted cable.

That web page also says:

"A sensitive earphone built around an electromagnet
might have an impedance of about 2,000 ohms"

Well, headphones have tended to settle on a standard
of 32 ohms, which is more electrical load and for
the same voltage level, uses a bit more power. If the
output voltage is around 1V from the MP3 player, then
V^2/R gives 31mW per ear.

In the article here, they claim

https://www.shure.com/en-GB/support/...specifications

"Earphones and headphones range from 8 Ohms to 600 Ohms
or higher. The audio source (the headphone output) also
has an impedance rating. To obtain maximum power transfer
(all usable power from the source reaches the earphones)
impedances should match. However, that's rarely the case."

And we hardly ever worry about the "matching" part and the
"loss" part. Instead, we might worry about "overloading"
the output.

And the MP3 player is probably designed for a 32 ohm load,
which is what we might expect in a 1/8" output jack ecosystem
with 1VRMS output voltage to be expected.

I don't think you're going to kill the device, unless
it states on the output "only for usage with an amplifying
device".

I think I may have had a telecom headset at one time,
and that was around 600 ohms and the ear pieces were
wound with many turns of fine wire (probably #36 to #40
or so). That would be an example of a high impedance
electromagnetic design. But the headphones I have
now are 32 ohms, and would not be nearly the same
construction.

I think it's a safe guess the battery life will be
shorter. I don't think it will kill your MP3 player.
If the MP3 player was "bundled" with earbuds or the
earbuds were permanently affixed to the player, that
would imply something about the adequacy of the design.
(Only designed to work with particular earbuds.)

But if you've ever worked with these, they're amazing.
They're very good on power consumption. My crystal radio
used to give room filling sound, just with the levels
coming out of the earphones lying on the table. No amplifier
or battery source or anything. Just energy picked out
of the air, rectified and presented to the phones. Strictly speaking,
you have to know the output device can drive a load
like this, which is mostly capacitive. The 741 OpAmp
might not like a load like this, and you'd have to put
a 50 ohm resistor into the output to change the pole
a load like this causes.

http://catalog.miniscience.com/catal.../Earphone.html

I think it's safe to try, unless the instructions for
the device specifically limit the kinds of loads it
will accept. There are electronics with 600 ohm output
impedance, and if you plug in a 32 ohm load to those,
there's almost no signal to listen to.

The MP3 player is unlikely to drive 2 ohm, 4 ohm, or
8 ohm speakers, and those could damage it (depending
on whether it's impedance protected or not).

Paul


I don't have the specs for the MP3Player, it's pretty old.

The earbuds:

https://www.philips.co.in/c-p/SHE135...specifications

The Headphones:

https://www.usa.philips.com/c-p/SHL3...and-headphones

(Not my exact model, but near enough)

I tried it. Didn't break anything, but I had to turn the
volume up 3 notches to get same volume.

Note Maximum power input 50mW vs 1000mW
Impedance 32 Ohms vs 24 Ohms
I have no idea what that means.


OK, so V^2/R = V^2/32 = 0.050, V = 1.26volts (earbud max input)

= V^2/24 = 1.000, V = 4.9 volts (headphone max input) (eardrums might not like this)

The headphones, to reach their maximum power, need
more voltage than typical line level computer type
devices would deliver. The MP3 player is probably 1V
to 1.2V perhaps on amplitude. If you did put 4.9V
into the headphones, you'd probably lose an eardrum.
So while the headphone elements can accept that
power level (1000mW), your eardrums might not like
that. The 50mW on the other hand, is likely a better
value. Somewhere between 33mW and 50mW should be comfortable.

The headphones are a slightly heavier load (ohms lower,
means heavier load).

The MP3 player might have a small amount of trouble
driving a load like that. But the value is not far
off from the "expected" value.

The Shure web article talks of "matching", but at least
on computer audio right now, the actual output impedance
of HDAudio chips is in the vicinity of 1 ohm. No attempt
is made to "match". No attempt is made to set the
output impedance to 32 ohms, to "match" a 32 ohm ear bud.
There is no appreciable voltage divider action as a result.
When an HDAudio chip drives out a 1V signal, the low
output impedance sees to it that pretty well the entire
1V ends up applied to the ear buds.

Your MP3 player could be different. It might have a higher
output impedance, and "divide" the output power as heat
in the MP3 transistor output stage and power in the
headphones. So when you use a 24 ohm headphone, the MP3
player itself might get a bit warmer.

There are ways for you to test these properties with a
multimeter and a collection of suitably-sized power resistors.
You can work out the output impedance of the MP3 player.
You can determine its ideal output voltage, as well as
study how it handles loading and draw a load line or whatever.
Hours of fun for someone with nothing better to do :-)

Paul
  #5  
Old September 27th 19, 03:28 PM posted to alt.comp.hardware.pc-homebuilt
Shadow[_2_]
external usenet poster
 
Posts: 190
Default Ping Paul - silly question - intelligent answer please.

On Fri, 27 Sep 2019 00:09:38 -0400, Paul
wrote:

I don't have the specs for the MP3Player, it's pretty old.

The earbuds:

https://www.philips.co.in/c-p/SHE135...specifications

The Headphones:

https://www.usa.philips.com/c-p/SHL3...and-headphones

(Not my exact model, but near enough)

I tried it. Didn't break anything, but I had to turn the
volume up 3 notches to get same volume.

Note Maximum power input 50mW vs 1000mW
Impedance 32 Ohms vs 24 Ohms
I have no idea what that means.


OK, so V^2/R = V^2/32 = 0.050, V = 1.26volts (earbud max input)

= V^2/24 = 1.000, V = 4.9 volts (headphone max input) (eardrums might not like this)

The headphones, to reach their maximum power, need
more voltage than typical line level computer type
devices would deliver. The MP3 player is probably 1V
to 1.2V perhaps on amplitude. If you did put 4.9V
into the headphones, you'd probably lose an eardrum.
So while the headphone elements can accept that
power level (1000mW), your eardrums might not like
that. The 50mW on the other hand, is likely a better
value. Somewhere between 33mW and 50mW should be comfortable.

The headphones are a slightly heavier load (ohms lower,
means heavier load).

The MP3 player might have a small amount of trouble
driving a load like that. But the value is not far
off from the "expected" value.

The Shure web article talks of "matching", but at least
on computer audio right now, the actual output impedance
of HDAudio chips is in the vicinity of 1 ohm. No attempt
is made to "match". No attempt is made to set the
output impedance to 32 ohms, to "match" a 32 ohm ear bud.
There is no appreciable voltage divider action as a result.
When an HDAudio chip drives out a 1V signal, the low
output impedance sees to it that pretty well the entire
1V ends up applied to the ear buds.

Your MP3 player could be different. It might have a higher
output impedance, and "divide" the output power as heat
in the MP3 transistor output stage and power in the
headphones. So when you use a 24 ohm headphone, the MP3
player itself might get a bit warmer.

There are ways for you to test these properties with a
multimeter and a collection of suitably-sized power resistors.
You can work out the output impedance of the MP3 player.
You can determine its ideal output voltage, as well as
study how it handles loading and draw a load line or whatever.
Hours of fun for



someone**
with nothing better to do :-)


PS **someone that knows how to use his multimeter.....

I'll stick to the earbuds. They're so cheap I just buy new
ones when they get clogged up. The MP3 player OTOH is no longer
available here in Brazil. All you can get are those MicroSD-based
players with built-in batteries. My wife bought one, and it lasted 6
months. My MP3 player is 10 years old.
If it ain't broke....
TY
[]'s


--
Don't be evil - Google 2004
We have a new policy - Google 2012
 




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