Does the 5v input can be given directly from a 3.7v 2000mah battery . or i need a dc step up booster to 5.5v as u suggested . And also man , i don't know what a filter is can you give a diagram of with whatever components ?? or can u do a seperate video about filters low pass high pass with easy diagrams ??
According to the datasheet of the Pam8403 the supply voltage range is 2.5 to 5.5 volts so it should work just fine but you need to use a protection board for the Li-Ion battery. I will do a separate video about these passive filters, now I'm working on a DIY bluetooth speaker video which I will upload in the upcoming weeks and after that I might do a filter video because it got requested several times.
Apropos bad ideas - powering an amplifier through a breadboard. 10 Ohm? 100 Ohm? Who knows. By the time it arrives down there at the chip, it's unlikely to be nice 5V any longer. I also notice a measurement irregularity - if you are reading 5V 180mA on the input coming out to 0.9W, then to make up 1.2V RMS on the output, the load impedance would come out to 1.6 Ohm, which... obviously isn't the case. Assuming those are 4-Ohm speakers, at 1.2V RMS, they would be consuming 0.36W, so you are experiencing a lot of power loss along the way somewhere, as expected efficiency of the chip is above 70% at such moderate loads. I suggest that the power loss may be occurring in the breadboard rail. You don't need a reconstruction filter for audio quality - at all. Limits of speaker response and hearing form the reconstruction filter. While avoiding RF rudeness may be worth some precautions, looking at just the amp and speaker, you don't need or want an output filter.
I've tried to connect directly the power supply leads to the board and adding the capacitor there but there was no noticable difference. You are right that it won't be a nice 5V but it was around 4.9-4.95V and on the breadboard the loss was not significant. This module is advertised to work from 2.5 to 5V so what's the situation when the supply voltage goes down to, let's say, 3.4 volts (if a Li-ion battery is the supply)? When I was measuring the supply current drain (180mA) there was a lot of loss in the circuit, as you noticed, the breadboard rail, test leads of the multimeter (where the supply voltage was going through), the coil had also a resistance (if I remember well it was around 0.6Ω). I only have these instruments to work with, and I'm still learning a lot how to become better. I've connected the coil to be able to measure and see the output better on the oscilloscope, if I used only a speaker the signal was too hard to measure and using a speaker to measure the output power of an amplifier can really upset the neighbours. When I measured the output power, I had to use power resistors which had no inductance, so I had to add a coil. It is written in the datasheet that: 'When testing the PAM8403 without LC filters by using resistor instead of speaker as the output load, the test results, e.g. THD or efficiency, will be worse than those of using speaker as load.' I should have mentioned this in the video... Thanks for the feedback and highlighting my mistakes and thanks for watching!
“The board is 10 to 20 cents!!” Broooo i literally bought a two pack of the 8403 (alongside a 2 pack of 8610) and it turned out to be 15 dollars a few months back wtfffff - someone who was VERY fixated on the Pam boards in late 2022 early 2023
Taking notes 📝
You want to build an amplifier or you are just thinking about buying this circuit for testing? Thanks for watching!
Does the 5v input can be given directly from a 3.7v 2000mah battery . or i need a dc step up booster to 5.5v as u suggested .
And also man , i don't know what a filter is can you give a diagram of with whatever components ?? or can u do a seperate video about filters low pass high pass with easy diagrams ??
According to the datasheet of the Pam8403 the supply voltage range is 2.5 to 5.5 volts so it should work just fine but you need to use a protection board for the Li-Ion battery. I will do a separate video about these passive filters, now I'm working on a DIY bluetooth speaker video which I will upload in the upcoming weeks and after that I might do a filter video because it got requested several times.
Thanks man really helpful. Looking forward for that diy bluetooth speaker. I will appreciate if can build a mini wireless sub woofer.
It won't be mini, a 100mm diameter subwoofer will be built in along with a tweeter and a full range speaker.
Excited for your video
Thanks, and thank you for watching and commenting!
Upto How many watts can it handle?
The claimed output power by the manufacturer is 3 watts per channel. I could measure 1 watt power per channel at best. Thanks for watching!
What about PAM8406?
I already have the circuit and I will make a video about that too, I just have to finish other videos first.
I'm ur new subscriber. How to reduce noise from this bluetooth module ?
The noise can come from several noises, power supply, audio source etc. What kind of power supply do you use?
Apropos bad ideas - powering an amplifier through a breadboard. 10 Ohm? 100 Ohm? Who knows. By the time it arrives down there at the chip, it's unlikely to be nice 5V any longer. I also notice a measurement irregularity - if you are reading 5V 180mA on the input coming out to 0.9W, then to make up 1.2V RMS on the output, the load impedance would come out to 1.6 Ohm, which... obviously isn't the case. Assuming those are 4-Ohm speakers, at 1.2V RMS, they would be consuming 0.36W, so you are experiencing a lot of power loss along the way somewhere, as expected efficiency of the chip is above 70% at such moderate loads. I suggest that the power loss may be occurring in the breadboard rail.
You don't need a reconstruction filter for audio quality - at all. Limits of speaker response and hearing form the reconstruction filter. While avoiding RF rudeness may be worth some precautions, looking at just the amp and speaker, you don't need or want an output filter.
I've tried to connect directly the power supply leads to the board and adding the capacitor there but there was no noticable difference. You are right that it won't be a nice 5V but it was around 4.9-4.95V and on the breadboard the loss was not significant. This module is advertised to work from 2.5 to 5V so what's the situation when the supply voltage goes down to, let's say, 3.4 volts (if a Li-ion battery is the supply)? When I was measuring the supply current drain (180mA) there was a lot of loss in the circuit, as you noticed, the breadboard rail, test leads of the multimeter (where the supply voltage was going through), the coil had also a resistance (if I remember well it was around 0.6Ω). I only have these instruments to work with, and I'm still learning a lot how to become better.
I've connected the coil to be able to measure and see the output better on the oscilloscope, if I used only a speaker the signal was too hard to measure and using a speaker to measure the output power of an amplifier can really upset the neighbours. When I measured the output power, I had to use power resistors which had no inductance, so I had to add a coil. It is written in the datasheet that: 'When testing the PAM8403 without LC filters
by using resistor instead of speaker as the output load, the test results, e.g. THD or efficiency, will be worse than those of using speaker as load.' I should have mentioned this in the video...
Thanks for the feedback and highlighting my mistakes and thanks for watching!
thanks for for such a hard work.
Thanks for wathing!
it's clearly a pro tip to use ethernet cabling for the connections
nice audio video description
Thanks!
“The board is 10 to 20 cents!!” Broooo i literally bought a two pack of the 8403 (alongside a 2 pack of 8610) and it turned out to be 15 dollars a few months back wtfffff
- someone who was VERY fixated on the Pam boards in late 2022 early 2023
So nice!