Audio amplifier design

I am making a audio amplifier using tda2030 or tda2050. It will connected to my raspberry pi and will be on 24*7. There is a continuous hum noise when i connect it to Pi but no noise when connected to mobile. Please suggest me a way to eliminate the humm. And is there a way to keep the amplifier in a sleep state unless an audio signal is received because keeping it always on will heat it up significantly. These are the circuits i will be using. And i would power it with 5V (most preferable)or 12V.
**broken link removed**

You show the datasheet circuit that has a positive supply and a negative supply but your schematic has no supply (single positive 5V or single positive 12V?). Its input must be biased at half the supply voltage if a single positive supply is used and the minimum supply must be observed.
Your output zobel network has wrong values.
Your output is missing the protection diodes.

audioguru said:

Your output zobel network has wrong values.

Click to expand...

It has 'different' values to the datasheet example, but they look perfectly fine, and probably better than the datasheet values. There's nothing critical about zobel network values, and they often change considerably during the manufacturing life of a product.

Nigel and Guru,
I drew a red line connecting PWR_GND and SIG_GND.
What do you think?
Ron

The amplifier still has no power supply shown.