Simple 1/8 jack question

T

The549

a hack
Someone who I'm working for is using a headphone splitter (the small male to 2 female plug) plugged into his laptop.
-Going out from one female split is the cable to the stereo with dual rca on the ends.
-Going out from the other female side is an INput from his other computer.

It works in that both computers can play through the stereo at the same time. I'm sure the resistance isn't enough to prevent that. My question is whether or not there can be damage done to the laptop?
 

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No.

Putting a cable from the soundcard out of one computer to the input of another (or even the same computer for loopbacks) is an old technique.

Just keep the levels reasonable so there is no distortion.

No damage will result.
 
It will work, but the signal from each device will drop in level, perhaps significantly, and could be degraded. This is because each device will see the output impedance of the other as a load, which could be excessive, and cause the performance of each device to decline.

If you want to improve matters, add a 1K ohm resistor (or so, it's not critical) in series with both outputs.

In any event, the laptop won't be damaged.
 
Ok, if this were a more important connection, I'd put the resistors in. But where would they be wired into? 3 resistors for each stereo cable - left, right, ground?
Thanks
 
My first setup with a computer many years ago I actually had piggybacked Y jacks hooked up to the output of my sound card. The first was a stereo Y adapter, and then into one side of that I had a stereo-to-L/R-mono splitter. The splitter outs went to the L/R tape ins of my mixer and the remaining stereo out went to my desktop computer speakers.

I ran that setup daily for several years with no issues whatsoever.

G.
 
The549 said:
Ok, if this were a more important connection, I'd put the resistors in. But where would they be wired into? 3 resistors for each stereo cable - left, right, ground?
Thanks
Click to expand...

No, just in series with left, and series with right.

PS to Glen--splitting an output is different than sharing an input; splitting an output is normally fine.
 
mshilarious said:
PS to Glen--splitting an output is different than sharing an input; splitting an output is normally fine.
Click to expand...
My bad...I think?! Going back and re-reading his first post I definitely misunderstood. Problem is I now understand even less what he has setup. The way I read it, he has an input on one brach of the Y, an output on the other, and an output on the root; i.e. he has the Y set up kinda "sideways". I don't get it.

G.
 
SouthSIDE Glen said:
My bad...I think?! Going back and re-reading his first post I definitely misunderstood. Problem is I now understand even less what he has setup. The way I read it, he has an input on one brach of the Y, an output on the other, and an output on the root; i.e. he has the Y set up kinda "sideways". I don't get it.

G.
Click to expand...

This coworker has things reversed, in a manner. Normally, a headphone splitter takes one input and splits it to outputs, and the genders of the connectors match (the male end plugs into the output of the audio device, and two 1/8" trs cables are plugged into the female outputs of the splitter).

In this instance, the person is reversing the usage of the splitter - they are running two separate audio sources into it, and running the third jack out to a set of speakers... i.e. the male jack is plugged into the audio output of a laptop, but instead of going to two audio playback devices (like two sets of headphones), one of the "outputs" of the adapter runs to stereo speakers, but the second output actually has the audio from another computer running INTO it. I've done this before myself, and worried about this very thing, but it always seemed to work fine. I'll draw a pretty MS Paint picture that makes a little more sense since Im bored :D
 

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SouthSIDE Glen said:
My bad...I think?! Going back and re-reading his first post I definitely misunderstood. Problem is I now understand even less what he has setup. The way I read it, he has an input on one brach of the Y, an output on the other, and an output on the root; i.e. he has the Y set up kinda "sideways". I don't get it.

G.
Click to expand...

Yep. It's still all a parallel connection though, the gender of the connector doesn't matter.

OP, when/if you add resistors, make sure they go inline with both output devices, not with the input device (the stereo).
 
Which in this case would mean a total of 4 resistors, right? And that would be to make the outputs higher resistance than the inputs for the correct signal flow or loading?
 
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