Hi, recently I putted an hdmi tv decoder to my mother's tv, and the thing is this last christmas my brother and I bought her some wireless headphones and she was using them until now. She can't use them anymore because the tv doesn't have audio output when you connect something via hdmi.
So I figured out, well, I just solder some cables to the tv speakers, and I adapt it to a female jack, so then I can plug the wireless emitter base there and problem solved. I know how to do this, and in fact it works, only that I hear a horrible soft but loud "bzzz" kind of sound along with the tv audio (so this indicates that the cables are not mixed up, right? if it was shorted (example l/r channel connected to ground) I wouldn't hear anything but a loud low tone, right?)
The speakers on the tv are rated 8ohm 15w, and I forgot to put a switch to disable the speakers in order to hear just through the jack and not from both the tv and the jack, does anyone here think this could be the problem? The noise appears when I connect just a jack adapter (6.35mm jack to 3.4mm jack) , with no device attached to it.
Maybe there's something wrong with what I did? I don't think I made any mistakes but I can't find a solution for this problem... The tv speakers have a big terminal and a small terminal, the big one being the ground and the small one being Left or right channel, and I soldered those to the matching tabs on a TRS 6.35mm female jack, using the pinout reference in electrodroid. So It was pretty easy to do, no idea what could be wrong there... Maybe the cables that run from the speakers to the jack are too long? Or the cables I used are not adequate for this? (just regular thin copper wire with insulation like 2mm thick) Or should I solder those cables in the pcb instead of in the speakers ? Just thought it would be easier to solder it to the speakers but I have come up with this idea right now, that might be the problem. But again, no idea.
Also, if I put a switch to switch the audio output through the speakers or through the female jack, could I do that with a simple shaft toggle switch or would I have to do it via some circuit? I would appreciate a lot if anyone could help me with this
Thanks