Instructables

How do I make a headphone jack cancel the output of the speakers when headphones are plugged in?

I made a small stereo amplifier with 3 inputs, and L and R outputs for speakers,  but how do i make another output that cancels out the speaker output?

EMuentes11 months ago
At radio shack it's called a 1/8" Stereo Panel-Mount Phone Jack.
EMuentes11 months ago
I was trying to find this plug everywhere but couldn't...

until I found out that it's called a 3.5mm closed circuit stereo headphone jack.

That brought up tons of options for purchase!

Thought you, or anybody looking for the same answer, would want to know.
aelias363 years ago
They sell 1/4" jacks that get bypassed when nothing is plugged in, called switch contact connectors. That should be fine for your purpose.

You can see in the picture that when nothing is plugged in to the jack, elecricity flows normally, but when a connector is plugged in, the signal gets sent to the connector instead.
Jack-plug--socket-switch.jpg
Seconded. As soon as you plug into the jack, the 'spring loaded' connectors in the jack are both connected to the male plug, and disconnected internally from the speakers.

The speakers are ALSO connected to the jack so that when the connector is inserted, the speakers are cut.

In the picture above, you can see how the tip of the plug presses the connector 'up', which disconnects it from the plate just inside of it - that plate goes to the speakers. No connection = no speakers.
metsfan1938 (author)  frollard3 years ago
So does this mean I should wire the jack in parallel with the speakers, or series?
Series, sorta.

The jack will have input and outputs

Input is your signal, output goes to your amplifier to your speakers. When the plug is inserted in the jack, the signal is cut off to the amplifier, and the speakers shut off, and the headphones get the signal.
Oh, and 1/8" jacks are also made if that's what you want.