I am building an arduino alarm clock / radio.
The project I was following uses a TDA7053A chip for the amplifier, which has a digital input for volume.
I could not get one of those chips and instead got the TDA7053, which does not have digital volume control.
How does one then adjust the volume digitally in such a case?
Also, how does an analog volume control work? (in case digital is not possible.) Is it just a pot that has one side connected to the audio signal and the other to ground, with the middle pin going to the input of the amp?
As far as I understand neither are controlled digital. The 7053A-version requires an analogue DC-signal to set the volume, by changing voltage on the dc-pin, volume is changed.
( http://www.nxp.com/documents/data_sheet/TDA7053A.pdf, page 10)
You can indeed use pot meters to control the volume, next schematic should work.
If you want digital control, use a Digital Potentiometer, the article describes just one, but many different types are available.
Thanks Simpson.
That's kind-of what I thought. I was worried though about shorting the output to ground when resistance on the pot is 0. Is this harmful?
@sonnyyu I don't exactly want to wait months for one to arrive in the post. I live in the middle of nowhere.
HI,
Shorting the INPUT pins 2 and 6 of the amplifier to gnd is fine, as it is the only reliable way of making sure that no audio is passed to the amp and the input does not pick up any noise while the amplifier is silent.
