eliminate the common mode hum , Silence audio o/p

[bimbla]

Silence audio o/p

In audio circuits, the control circit invariably produces some sort of hum. No matter what you do, getting silence at the

output is very difficult.
What are the different ways to obtain silent o/p? I autoroute my boards having control and power sections on the same board

using Layout Plus.

I am using amps in bdg configuration in the final stage. Instead of bridging it in the amp circuit itself, I plan to invert

the final control signal and feed the complementary signals to two identical amps.
I hope that this will eliminate the common mode hum. I also hope that this will eliminate the need to have a turn- on delay

circuit along with the bulky relay.

All comments and views welcome.

bimbla.

 

[flatulent]

twisted pairs

The low level audio should be routed on shielded twisted pairs or coaxial type cables. Also, the level should be made large before going on long wires to such things as volume control variable resistors that are off the PC card.

 

[barrybear]

Even if you grounded thi input to the power amplifier the chances are that you would get a thump from the speakers at switch on, as the output stage stabalised.
The only option for quite start of your power amps would be to chose high quolity ICpower amps that have a mute pin that you can control at switch on to silence your output stage at switch on.

Barrybear