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I would like to at night use just my (unamplified) phone as signal for two speakers.

However, I also want to use them with an amplifier. To do so, would I need to just switch between the + cables, and join the other ones, or will doing so be potentially harmful to the phone? (since it is an ac current) or would I need to switch out all of the connections? (by using a switch with 4 channels)

I really like my phone, so I don't want to just try it.

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Mordern amps are usually bridged, that means each speaker is connected in a H-bridge setup. This allows higher output currents due to polarity reversal.

In your case that means you must switch all 4 wires - the speaker "minus" wires are not GND.

In contrast, the headphone minus wires are connected together as GND. The forth wire on the connector is for the mic.

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  • \$\begingroup\$ So, if I will join the "ground" ( I know it's not really that, but the black wires) together I am in risk of damaging my phone? Also, Thank you for your quick reply! \$\endgroup\$
    – user31191
    Nov 2 '13 at 17:28
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I would like to at night use just my (unamplified) phone as signal for two speakers.

In general, the audio output available from mobile phone is intended to drive earphones and is not suited to drive passive loudspeakers.

For passive speakers you will have to buy or build an amplifier or connect your phone via an adapter into your existing amplifier.

If your speakers are "active speakers" or "monitors", they will have an amplifier built in to them and may be able to produce an audible output from your phone. These types of speakers typically have a volume control on one speaker.

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Even active speakers expect line-level inputs, not the signal levels from earphone outputs. You can purchase attenuators that are intended to convert the audio signal levels.

I need to just switch between ...

The tradition solution for this is an audio mixer

enter image description here

With some knowledge of electronics, you can of course build a suitable circuit to connect your phone to your speakers and to switch the inputs of your speakers between two sources.

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  • \$\begingroup\$ Thanks, the speakers I'm using will provide a during the night suitable volume (they are going to be within 1.5 m from my head) but during the day I want to be able to pump up the volume. I just don't like to have the amp on all the time.I'll just use two switches to change all the wires to be on the safe side, then. Thanks, everyone! \$\endgroup\$
    – user31191
    Nov 6 '13 at 20:43

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