Hello again!!
I have bought yesterday a stereo amplifier kit, that uses TDA7262. I'll make a schematic for that PCB, but I think is a copy of the suggested application found in the datasheet
**broken link removed**
Even when I didn't posted the schematic yet, I guess the fail symptoms are very recognizable for an expert:
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Either when feeding the circuit with 12V battery or PC PSU:
- Very loud hum and interfence when the input (a 3.5 mm plug) is not connected to anything, or if touched with the bare fingers
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In the following cases, the PC PSU +12V and 0V rails are used to feed the cicuit:
- Loud ground loop when connected to a PC sound card. Grounding the circuit with the soundcard ground doesn't fix the problem
- When feed with signal coming from an iPod or external player, the circuit works perfectly
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Thank you in advance!