In alt.comp.os.windows-10, on Mon, 24 Aug 2020 14:24:23 +0200, "Carlos
E.R." wrote:

On 24/08/2020 06.26, micky wrote:
In alt.comp.os.windows-10, on Sat, 08 Aug 2020 21:13:51 -0400, micky
wrote:

In alt.comp.os.windows-10, on Sat, 08 Aug 2020 20:53:51 -0400, Paul
wrote:

micky wrote:
Now that I sometimes have the laptop and desktop running at the same
time, and I listen to web radio from whichever is doing a better job, I
wanted a Y-connector, to send both signals to the speakers.

There appeared to be many but most just split off the mic from
headphones. Another was 8 feet long but the part where the wires could
go in 2 directions to two sources was not shown. It definitely wasn't
all 8 feet. Another was only 20 cm long. I don't know what that is
in real numbers but I dont' think it will work, especially if the
computers were on opposite sides of even the same desk.

One was 6 feet long with totally separate wires. 6 feet is more than
enough but I think this means 12 feet. I have the url if you want.

But this last one had a warning, given liteally 3 times in the Amazon
webpage offering it for sale:
"Don't play two different audio at the same time. If the audio from
two different audio sources, more powerful output will be louder."

Well of course, and so what, and won't anyone notice this right away?

Is there a valid reason for this warning?

A foreigner teaching you some maths ?

That might be it. When the Chinese warn you that one sound might be
louder than another, that's enough to make me think MS might insist on a
password even when I'm alone.

The person neglected to consider if the signals
are identical, but one signal is upside-down with respect
to the other signal. The net signal output is zero :-)

PC#1 ----- R1 ------+
|
+---------- In, computer speakers, 10K input impedance
|
PC#2 ----- R2 ------+

You're allowed to make your own cables, you know.


So the resistors are meant to solve the problem that Carlos brought up??
Burning out one of the sound outputs.

It is not that easy.

It the resistors are high value, you hear nothing. If they are low, the
outputs are still in danger. Plus, there is the issue of impedance coupling.

I repeat: just don't do that.


Yes, but it's so much easier to buy.

This answer was when I thought I coudl just buy it.

For R1 and R2, you could make then both 390 ohms
or both 560 ohms, without too much impact on the results.

Carlos, you raised the problem more clearly to this newbie than Paul
did.

Do you agree that 300 or 560 ohm reistors oin the positive wires of the
Y-connector would keep the sound output from burning out?

It would render the speakers silent as well...


Okay, I won't do it. I trust you, even though I've never met you.
Having two computers running will probably be temporary anyhow, as
planned. I sort of like it but when I have one good computer, I won't
want to waste the elecfricity.