Help Headphone Jack Signal as Line Out

[Soul Searcher]

I want to use the headphone jack as a line out to go to an amplifier to use backing tracks on my phone. Apparently the phone detects the line impedance and stops the signal being sent. Does anyone know of a solution?

 

[olbriar]

I've never considered using the headphone jack as a line out. I've not looked but I'm sure the impedance and the power level can be found. Just guessing, a preamp that has a line in at the impedance, and then to your power amp. I'd be surprised even if you have a match, the power level is great enough to drive your amp. Hey... I'm often wrong lol. I hope another comes along that has more than a guess to offer. Good luck

 

[mikedt]

I want to use the headphone jack as a line out to go to an amplifier to use backing tracks on my phone. Apparently the phone detects the line impedance and stops the signal being sent. Does anyone know of a solution?

It should work like that. An amp is plugged into the phone jack, the phone should route the media audio to it. I've done that many times with various phones, amplified speakers, classroom PAs, etc. That's a main reason why I would never buy a phone that doesn't have a headphone jack.

Does the headset icon appear on the notification bar when the amp is plugged in?

 

[Soul Searcher]

It should work like that. An amp is plugged into the phone jack, the phone should route the media audio to it. I've done that many times with various phones, amplified speakers, classroom PAs, etc. That's a main reason why I would never buy a phone that doesn't have a headphone jack.

Does the headset icon appear on the notification bar when the amp is plugged in?

Thanks MikeDT. Yes the handset icon appears, but the signal is not getting through on this new phone, whereas it does on my old Galaxy S5. This is what someone else has said,

"The handset detects the impedance of the headset, which is typically around 300 Ohms, and switches the audio output to go out of the port. If use the headphone port to connect to audio line level equipment (eg amplifier) then the impedance of that is around 10,000 Ohm (10K) so the handset is not 'seeing' the amplifier as a valid connection, it appears as on open circuit. You can download an app called SoundAbout which allows you to manually control the audio output, so even if the amp is not detected you can still switch the audio to go out through the headset port.
I think this will solve your issue for the long term as the headset port is not specifically designed to connect to line level equipment and needs the low impedance seen in headsets to perform that switching decision."

I returned the brand new phone thinking the headphone port was defective. They gave me new one, but I haven't opened it yet. I know I'm being cautious ... but I want it to work!