Coupling Audio Stages Together

Thread Starter

irobot2020

Joined Jun 1, 2016
6
I have two audio stages to connect.

The circuits are taken from the datasheets of the IC's. Would you use both capacitors C8-C6 (right channel) and C9-C7 (left channel) in series or just one cap? If just one cap, what value? Any resistors needed? Side note: The output impedance of the SI4735 chip is about 20K, the input to the TDA7052 is 10K.
interface.PNG

Side note: The output impedance of the SI4735 chip is about 20K, the input to the TDA7052 is 10K.
 

AlbertHall

Joined Jun 4, 2014
12,345
You will only need one capacitor for each channel BUT you should watch the dc level of the outputs and inputs if using polarised capacitors. The TDA7052 shows 0.47u capacitors and they can easily be a non-polarised type which avoids the DC problem.
 

Thread Starter

irobot2020

Joined Jun 1, 2016
6
Thanks Albert

Question is, do I use a 4.7uf or .47uf to couple these stages? I have run into this issue many times before when connecting various audio circuits together.
 

crutschow

Joined Mar 14, 2008
34,280
Note that the input bias current (Ibias) is up to 300nA so you need a resistor to ground to provide that.
The application diagram shows 5k:
upload_2016-6-5_7-51-4.png
The coupling capacitor should then be ≥4μF (4.7μF is fine) to get a 20Hz rolloff.
 

Thread Starter

irobot2020

Joined Jun 1, 2016
6
Note that the input bias current (Ibias) is up to 300nA so you need a resistor to ground to provide that.
The application diagram shows 5k:
View attachment 107254
The coupling capacitor should then be ≥4μF (4.7μF is fine) to get a 20Hz rolloff.
So am I correct in saying that the 5K R(s) is also effectively changing the input impedance to around 5K, or maybe a little less?
 
Top