Thanks Rick, Peter, for the information. I did some checking after reciving the posts from you guys, and what I find is this: The TV has a 2 pin mains plug (no earth); neither of the two seem connected to the PCB ground (the ground on the Audio IN, Video IN plugs). Also, neither of the speaker wires seems directly connected to the PCB ground. On this basis, am I right in assuming that a workable solution might be: 1) a 100 ohm resistor in series with the speaker / headphone socket, always in circuit regardless of whether the headphones are plugged in, for short circuit protection, and 2) an audio transformer to drive the headphones; this comes into circuit only when the speakers are cut out, and would give complete isolation to the headphones? The only issue I foresee is that I still would short the circuit at the socket while inserting the headphones, but now it would be thru' the 100 ohm resistor. Would this work? And, would it be safe? ----- Original Message ----- From: "Anand Dhuru" To: Sent: Monday, July 01, 2002 10:00 PM Subject: Re: [OT]: Audio Amplifier Please excuse the completely OT nature of this post; its just that I have seen such great talent in various branches of electronics on this list, I feel tempted to put my query here. I have a TV which came without a earphone socket. I just wired in a socket the usual way (speaker automatically gets disconnected if you plug in a headphone), and it seemed to work fine...for a few seconds. After that, there was a bang, and the amplifier chip within blew up. The chip used is Philips TDA 8945S. The TV speaker has an impedence of 8 ohms; the headphones are of course, a much larger impedence. This being the case, why would the chip blow? Do some amplifiers also get damaged if the load impedence is *higher* than the one specified? In which case, would a resistor network that still offerred about 8 ohms to the amplifier even when the headphone is connected help? I just might have inadvertantly shorted the output wires (for not more than a second or two, I'm sure). This chip is supposed to have both, thermal and short circuit protection. Could the possible short then still have caused the problem? I have replaced the chip, but before trying out the headphone again, I would like to get some advice from you folks out there. Regards, Anand Dhuru -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics