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I would like to connect 2 devices (player and tablet) to my headphones; would it be safe to do so using a simple Y splitter?

(Two male 3.5 mm connectors would to go both devices and one female 3.5 mm connector to the headphones)

sorry for the lame question, I don't want to damage anything

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This in NOT a good idea.

The general rule is that you can split signals, but you cannot merge/mix them without special circuitry.

That's why you need a mixer for: to MIX signals. Here's a small, passive mixer that could well do the job. (See also here.)

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I once accidentally connected the same speaker to 2 different amps and blew out one of them from the power of the one amp flowing into the other.

Headphone outputs have a much lower output level, but some devices may be more sensitive than others to signal being sent back in through the output.

I would recommend playing it safe and getting a small inexpensive mixer. It will give you much better control of the mix and prevent damage to your equipment.

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  • thank you for the warning. Unfortunately, these mixers are too big (I need something I can put in my pocket). Thanks again.
    – Steve V
    Jul 10, 2013 at 15:51
  • Here is the closest thing I could find to what you are looking for. You might want to try searching for a DIY project. You should be able to find a simple mixer project similar to this headphone amp.
    – Friend Of George
    Jul 10, 2013 at 16:14
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I don't think this is going to work well. I've never seen a passive device for blending signals together. You might be able to get something out of it and I'd hope that the audio hardware is designed well enough to avoid serious damage since the power levels are low, but I'd expect the signal might be quite a mess when you try listening to it.

To do it right, you really need something that prevents backfeed and isolates the two inputs, that requires power unfortunately, which either comes externally or from the signal itself (which would result in massive attenuation thus not suitable for powering headphones.)

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  • There definitely are passive mixer circuits. epanorama.net/circuits/linemix.gif Like you said though, they lower the power significantly.
    – Brad
    Jul 10, 2013 at 14:24
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    @Brad - yeah, I found the exact same circuit while looking for a passive design. I actually stopped looking when I found that one because it demonstrated the problem so well.
    – AJ Henderson ♦
    Jul 10, 2013 at 15:43
  • could you suggest a schematics I could follow in order to build an active device? (something as simple as possible, I can weld, but I know very little about building electronics).
    – Steve V
    Jul 10, 2013 at 15:54
  • @SteveV - you would honestly be better off buying something like the little $20 mixer that FriendOfGeorge linked to. You'll end up spending more on parts to build one yourself.
    – AJ Henderson ♦
    Jul 10, 2013 at 15:55
  • @AJHenderson I don't mind spending money, but I need something small (I tried to find a pocket-size mixer but no luck so far)
    – Steve V
    Jul 10, 2013 at 15:57

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