Earphone 3.5mm socket on Tx

[IanF9X]

Hi any advice on fitting an 3.5mm mono audio socket to bypass the speaker. I've fitted a maplin one which is nice cause it locks out the speaker by disconnection. What I am finding is that the earphones are heating up. Now I have paired up a pair of cheap stereo earphones as mono and just wondering if this has had a bearing on them heating up or perhaps too much current from the 9x board. Any advice on what size of resistor I could put in line so I don't roast my ears

[jhsa]

Is that the stock 9x board with the stock beeper, or do you have a voice module installed?

João

[IanF9X]

Is that the stock 9x board with the stock beeper, or do you have a voice module installed?

João

Joao I've got the 9xtreme board installed. Just piggybacking the mono socket from the speaker connections from the 9xtreme. When earphones plugged on speaker is out of circuit by virtue of the 3.5mm socket design. But earphones are getting warm

[jhsa]

Ahh yes, sorry, I'm on the phone so I've failed to see you did post on the 9xtreme forum.
I really find it strange that the headphones are getting HOT???
Unless there is some DC voltage always present at the audio output?
Do you have a capacitor say 47uF you can place in series with the headphone? Then see if it still happens.
Also can you draw a little schematic of your connections? This is all I can think at the moment just afer waking up. Need coffee

João

[MikeB]

For information, the audio amplifier on the 9Xtreme is a class D amplifier. This means it outputs a high frequency square wave on both signals.
Certainly, try a capacitor.
For a resistor, I'd suggest 22 ohms up to 100 ohms.

Mike.

[jhsa]

Maybe a capacitor should be already placed on board on the next revision of the board?
This should stop any DC component..
João