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Need a protection circuit?

hi
i am making my own speaker system. i am using this amp http://www.dealextreme.com/p/y148-audio-amplifier-module-93121
the issue im facing is that a few days ago i power this amp with a smps 12v 1amp supply and it was working fine till something went wrong with the psu and there was a spark in the psu, the major problem which occurred  was that this caused a surge which travelled through the amp to my audio source which in this case was my computer. i ended up frying my sound card .
can anyone help me make some kind of protection circuit which allows audio signals to pass through but does not let current from the psu pass through.


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Normally, you would/should have a blocking capacitor to protect the sound card.
cfrek (author)  steveastrouk4 years ago
i was thinking of adding a capacitor in series but i am not sure of the value of the cap. i need a value which does not affect my audio frequency.
depends on the input impedance of the amp, you can try something like 1uF polyester.
You probably need to check your amp. If your sound card was damaged by the surge then your amp will have problems as well. You may want to consider a different amp module. A surge from the power source shouldn't have hurt the PC unless there isn't good enough isolation between the voltage inputs on the amp and the audio inputs from the PC. Can you rule out any possibility that the amp was faulty and cause the short in the PSU and subsequent surged into the PC?
cfrek (author)  mpilchfamily4 years ago
the amp is working fine no issues with it but im a bit concerned as i generally play music with my pc or phone.
i was using a very cheap low quality supply. A ceramic cap on it blew when this happened and caused this issue. i have experimented quiet a bit on the amp and i don't think anything is wrong with it but just to be on a safer side i was looking for a protection circuit.
frollard cfrek4 years ago
What he's saying is...
Don't trust your expensive electronics (computer/phone) to a cheap amp. It is the weakest link, it has proven to destroy other things, just replace it.