Hello, all!
I am building a small amplifier using the PAM8403 chip and would like your input as to which capacitors would really be necessary and what values you might prefer.
I have been a bit confused by the datasheet which seems to suggest the adding of a lot of different capacitors. Elsewhere i have been told that many of the suggested capacitors are already on the finished version of the board. I would like to keep it simple but i want decent quality sound. I don't expect it to be fantastic but i would like to get the best sound out of the board for bluetooth and phone/ipod music playback.
I have already used a 16V 10uF cap on the DC input voltage and it yields a pop on power up but seems to do the job otherwise. I will be powering the board with 3 AA batteries and the speakers will be full range 4" or 5" speakers 4ohm.
EMI is a concern. I have noticed that apple phones in particular create a "click click click" on the line that comes and goes and is slightly unpleasant. I would like to know if there is a way to remedy that. I have some ferrite beads available but i also have been told that they degrade the sound. I will start wiring up here in a few weeks and i didn't want to reinvent the wheel on this.
thanks ahead for any help.
http://www.diodes.com/datasheets/PAM8403.pdf
I am building a small amplifier using the PAM8403 chip and would like your input as to which capacitors would really be necessary and what values you might prefer.
I have been a bit confused by the datasheet which seems to suggest the adding of a lot of different capacitors. Elsewhere i have been told that many of the suggested capacitors are already on the finished version of the board. I would like to keep it simple but i want decent quality sound. I don't expect it to be fantastic but i would like to get the best sound out of the board for bluetooth and phone/ipod music playback.
I have already used a 16V 10uF cap on the DC input voltage and it yields a pop on power up but seems to do the job otherwise. I will be powering the board with 3 AA batteries and the speakers will be full range 4" or 5" speakers 4ohm.
EMI is a concern. I have noticed that apple phones in particular create a "click click click" on the line that comes and goes and is slightly unpleasant. I would like to know if there is a way to remedy that. I have some ferrite beads available but i also have been told that they degrade the sound. I will start wiring up here in a few weeks and i didn't want to reinvent the wheel on this.
thanks ahead for any help.
http://www.diodes.com/datasheets/PAM8403.pdf
Try following the data sheet exactly to start with, usually this is what will have been tested in house.......
thanks for the replies. i will probably have a good many more questions going forward. I really appreciate the help. i'm somewhat of a noobie.
This little amplifier has a great sound until you get about halfway up on the input gain coming from your device. whether it is a phone or ipod, etc. It seems that the more dynamic passages of some types of music that are not highly compressed yield square waves and distortion to the output. given the nature of how this is somewhat predictable, would it be possible to put a resistor at the analog input of some value to decrease the input gain across the board no matter what the input is from?
if so, what value do you suggest?
This little amplifier has a great sound until you get about halfway up on the input gain coming from your device. whether it is a phone or ipod, etc. It seems that the more dynamic passages of some types of music that are not highly compressed yield square waves and distortion to the output. given the nature of how this is somewhat predictable, would it be possible to put a resistor at the analog input of some value to decrease the input gain across the board no matter what the input is from?
if so, what value do you suggest?
wow! thank you very much for the help. i can see by your picture that the board you were using is labeled properly also. the one i have right now is not.
i had not seen a ferrite placed there before. interesting.
also i was planning on using a 1uF and 470uF and 1000uF in a stack where you have just one 2700uF filter on the input Voltage. I was basing that on the PAM8403 datasheet and also some reading of hifi preferences for a grouping of 3 caps for this filtering. Do you think that would pose any problems? totally unnecessary?
i had not seen a ferrite placed there before. interesting.
also i was planning on using a 1uF and 470uF and 1000uF in a stack where you have just one 2700uF filter on the input Voltage. I was basing that on the PAM8403 datasheet and also some reading of hifi preferences for a grouping of 3 caps for this filtering. Do you think that would pose any problems? totally unnecessary?
The LC-Filter is only for the BT-module. The 2700uF were determined empirical - is giving least audible noise here. The PAM8403 is silent by its own.
I see. thank you, Dr.
For the purposes of getting the best quality sound (not referring to EMI problems), which capacitors/resistors on these stock boards would you be most apt to replace or modify?
VREF? Input caps? Power supply caps? PVDD caps for the signal Left and right?
Quality of components and values are the biggest concern to me now. I have figured out what is actually on the board as it is shipped to me so thanks for the help on that.
For the purposes of getting the best quality sound (not referring to EMI problems), which capacitors/resistors on these stock boards would you be most apt to replace or modify?
VREF? Input caps? Power supply caps? PVDD caps for the signal Left and right?
Quality of components and values are the biggest concern to me now. I have figured out what is actually on the board as it is shipped to me so thanks for the help on that.
None. 🙂
(You may change the input caps to 1uF MKT if you dont like ceramics, but i won't garante that you'Ll hear any difference)
(You may change the input caps to 1uF MKT if you dont like ceramics, but i won't garante that you'Ll hear any difference)
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