How to select one input from multiple input? Audio amplifier TDA7297+ SDcard module + jack 3.5mm

Thread Starter

duykwe

Joined Nov 17, 2023
71
Hello everyone. I am new here. I am making an audio amplifier with TDA7297 15W+15W. I take the input from the jack 3.5mm and I also input from the SD card module (it can decode the data into audio signals already, it is called DFplayer mini ). I want there is a switch and when I switch it takes the input from the jack 3.5mm and switches off the SD card module, and when I switch to the SD card mode, it switches on and then plays when I hit the buttons or something. Is that possible? My background isn't so good, I'm a newbie so hope you guys can help me to figure this out. Thank you so much
 

Audioguru again

Joined Oct 21, 2019
6,608
You need to buy the DPDT switch and learn about how to connect the "double pole double throw switch".
One pole to switch the audio source and the other pole to turn the SD card module power on and off.
 

Thread Starter

duykwe

Joined Nov 17, 2023
71
You need to buy the DPDT switch and learn about how to connect the "double pole double throw switch".
One pole to switch the audio source and the other pole to turn the SD card module power on and off.
I had a look about DPDT switch. It works for selecting inputs, but when I switch to the jack 3.5mm mode, the SD card still on power. Is there any way that I can switch to Jack 3.5mm mode and turn off the SD card module at the same time?
 

Ian0

Joined Aug 7, 2020
9,497
I had a look about DPDT switch. It works for selecting inputs, but when I switch to the jack 3.5mm mode, the SD card still on power. Is there any way that I can switch to Jack 3.5mm mode and turn off the SD card module at the same time?
You need a 3-pole switch. They are quite rare as toggle switches, but you can find them as rotary switches.
 

Audioguru again

Joined Oct 21, 2019
6,608
A Single Pole switch can select one of two inputs or it can turn the SD module power on and off.
I said to use a Double Pole switch that has two switches in it that can do what you want.
Your description and photos in the other thread shows a mono single speaker.
 
Last edited:

Thread Starter

duykwe

Joined Nov 17, 2023
71
Is your audio mono or stereo?
It's a stereo audio amplifier.
A Single Pole switch can select one of two inputs or it can turn the SD module power on and off.
I said to use a Double Pole switch that has two switches in it that can do what you want.
Your description and photos in the other thread shows a mono single speaker.
It's just a demo, so I bought one speaker, but it will run in dual channels for a complete circuit. But I think I got your idea, I think I will try to find a triple one to complete it. Thank you so much!!
 

Audioguru again

Joined Oct 21, 2019
6,608
Yes, use a 3 pole double throw switch for stereo.
The cheap speaker you show will not play bass or very high audio frequencies. It will sound like an old telephone.
ALL speakers need an enclosure designed for its specs.
 

Thread Starter

duykwe

Joined Nov 17, 2023
71
Yes, use a 3 pole double throw switch for stereo.
The cheap speaker you show will not play bass or very high audio frequencies. It will sound like an old telephone.
ALL speakers need an enclosure designed for its specs.
This is really helpful. I have watched some video that they use formex 5mm to make the enclosure for the speaker, I think I will give it a try. Thank you so much!
 

Audioguru again

Joined Oct 21, 2019
6,608
If the size of the speaker enclosure matches the resonant frequency of the speaker in the enclosure them it will resonate like a bongo drum. The speaker specs will say the correct size of the enclosure and if it is sealed or ported.
Both speakers must be connected with the same polarities.
 
Top