Here is the content reorganized into a well-structured article:

**Eliminating Interference Noises in Audio Amplification**

As I was experimenting with my audio amplifier and Bluetooth music receiver, I encountered a frustrating issue - unwanted interference noises. These pesky sounds were ruining my listening experience, and I was determined to figure out why they were happening.

To start, I soldered the left and right channels to the amp inputs. After hooking up a speaker to the amp and connecting an audio cable from my phone, I could hear that the audio amplification worked just fine - no buzzing or interference noises whatsoever. However, when I connected the Bluetooth music receiver to the same power source, the problem persisted.

**Understanding the Source of Interference**

To investigate further, I examined the waveform of the sound and observed reoccurring pulses. Next, I hooked up a 1 ohm current shunt in series to the Bluetooth receiver's power line and measured the voltage across it. What I saw was alarming - the current drawn by the receiver looked similar to the interference sounds we were experiencing.

**Conclusion: The Cause of Interference**

The source of the unwanted noises became clear: the receiver's current draw was causing the problem. Since both the amplifier and Bluetooth receiver shared the same ground potential, noise was being injected into both the audio signal ground as well as the amplifiers' ground. It seemed that I needed to find a way to separate these power grounds.

**Testing the Empty PCB**

To rule out any issues with my custom-built PCB, I connected all components and signals to a pre-made amplifier PCB based on the PA M8 406 ICU. Unfortunately, even with this optimized design, the interference problems persisted - albeit at a lower level.

**Solutions to Eliminate Interference Noises**

After researching various solutions, I came up with three methods to eliminate the unwanted noises:

1. **Two Mains Power Supplies**: By using two separate power supplies, we can keep all noise-trading currents away from the amplifier. This isolation ensures that only a ground connection is made through the audio cable, eliminating most of the interference.

2. **Amplifier PCBs with Isolated Ground Pins**: Some amplifier PCBs come with ground pins and isolated analog ground pins. By connecting these to separate power grounds, we can minimize noise pickup.

3. **DC to DC Converters for Power Rail Isolation**: Another solution is to use a DC to DC converter specifically designed to isolate DC power rails. By placing this device in series with the Bluetooth receiver's power line, we can isolate its power ground from the amplifier's power grounds.

**Conclusion**

After experimenting and testing various solutions, I found that the most effective method was using two mains power supplies to separate the noise-trading currents from the amplifier. This approach proved to be the most successful in eliminating the unwanted interference noises.

I hope this article has been informative and helpful for those interested in audio amplification and Bluetooth music receivers. By understanding the source of the problem and applying these solutions, you too can enjoy cleaner, more reliable sound quality.

WEBVTTKind: captionsLanguage: enlet's say you just got yourself such a cheap Bluetooth music receiver from eBay and now you want to create a music system with it's by adding a power supply amplifier and speaker well I actually created such a system in one of my previous videos but back then I was having the problem that interference noises were clearly here Opel while using one 12 foot power supply for the amplifier and an additional five foods linear regulator for the Bluetooth receiver the simplest solution to get rid of the interference sounds back then was to simply use an additional five foods mains power supply to power the Bluetooth receiver but why exactly did this additional power supply solve the problem and other maybe cheaper ways to achieve the same interference free results let's find out in this video this video is sponsored by jl CPCB who increased their user base by 226 thousands and produced over 4 million 490,000 PCB designs in the past year of 2019 so why not give the service a try by uploading your Gerber files today and ordering your custom PCBs to properly recreate the interference problem I started by removing the housing of the Bluetooth music receiver after soldering a wire to its ground and fifoota pin I hooked it up to five foot power to find out that it still works fine and that my smartphone can connect to it now at this point we obviously need the amplifier from back then but since I could no longer find it anywhere I was pretty much forced to gather all the required components and start building a second amplifier based on the schematic and created back in the days and after around two hours of soldering the amplifier was complete and does not blow up when powering its with 12 volts perfect as the first tests I cut up a 3.5 millimeter audio cable in order to expose its three wiris after determining that the blue wire was grounds isola dates to the ground of the amplifier boards and afterwards I soldered the left and right channel to the amp inputs now after hooking up a speaker to the amp and the audio cable to my phone you can hear that the audio amplification works just fine and that there are no buzzing or interference noises whatsoever so next I used to fight fools linear regulator to step down the mandatory 12 volts amplifier voltage to 5 volts this way I can hook up the Bluetooth music receiver to the same power source and as you can see it works without any problems but as soon as I connected the audio cable you can clearly hear the interference sounds I was talking about early on so where do they come from to find that outs I firstly had a look at the waveform of the sound which looks something like this and is characterized by reoccurring pulses next I hooked up a 1 on current shunt in serious to the Bluetooth receivers power line and had a look at the voltage across it as you can see the current reporters of the reciever look pretty similar to the interference sounds we are experiencing so in conclusion that means that the receivers current draw is what is causing the unwanted noises and you can hear them since the amplifier as well as the Bluetooth receiver shall be same ground potential simplified speaking that means noise gets injected into the audio signal ground as well as the amplifiers ground and there is something we have to change in order to get rid of the buzzing but before finding proper solutions to this problem I want to prove that my empty sign is not the reason for this problem that is why I hooked up all of the components and signals to a premade amplifier ports based around the PA m8 406 ICU and as you can once again hear the interference problems to still exists but are a bit less horrible because this PCB design is way more optimized than my crude perfect soldering design so the first proper solution to this problem is like earlier mentioned by using two mains power supplies this way there's only a ground connection through the audio cable but all the noise trading currents are kept away from the amplifier because the power grounds are isolated from one another I actually built up such a two mains power supply circuits once again in order to let you hear that it truly does solve the problem the next solution is to use an amplifier ports which comes with a ground pin and then a ground or analog ground pin which are isolated from one another like with this TPA a 3 100 t2 amplifier ports this way by hooking up the audio signal ground to a ground and the power ground to ground we can keep most of the power noise away from the audio signal and as you can hear it drastically reduces the interference noises because of this solution you might think that isolating the audio ground from the power ground would always be the best solution and that is what the comment section underneath my videos and I thought as well that is why the third and supposedly best solution should be a ground loop isolator that sits in between the Bluetooth audio signal and the amplifier inputs and isolates the grounds from one another so I got myself such a ground loop isolator which after tearing it open later basically consists of two transformers which like already mentioned create a galvanic isolation between the inputs and outputs and after placing it in between the Bluetooth outputs and the amp inputs we can hear that it pretty much changes nothing when it comes to the interference noises so sadly I was wrong with this solution and we should focus more on creating a separate power ground for both devices and that brings us to the last solution which is a DC to DC converter suited for isolating DC power rails by simply placing it in serious to the fifl power line of the Bluetooth receiver we isolated its power ground from the amps power grounds and thus once again achieved pretty much the same effects two mains adapters would have achieved only at a smaller budgets and of course if you're using battery power then two mains adapters would not be possible and you would have to use this solution as a replacement and as you can hear the interference sounds are gone with this solution and I hope that you learned a thing or two through this video and maybe even use some of its ideas in your own upcoming projects as always thanks for watching don't forget to Like share subscribe and hitting the notification Bell stay creative and I will see you next timelet's say you just got yourself such a cheap Bluetooth music receiver from eBay and now you want to create a music system with it's by adding a power supply amplifier and speaker well I actually created such a system in one of my previous videos but back then I was having the problem that interference noises were clearly here Opel while using one 12 foot power supply for the amplifier and an additional five foods linear regulator for the Bluetooth receiver the simplest solution to get rid of the interference sounds back then was to simply use an additional five foods mains power supply to power the Bluetooth receiver but why exactly did this additional power supply solve the problem and other maybe cheaper ways to achieve the same interference free results let's find out in this video this video is sponsored by jl CPCB who increased their user base by 226 thousands and produced over 4 million 490,000 PCB designs in the past year of 2019 so why not give the service a try by uploading your Gerber files today and ordering your custom PCBs to properly recreate the interference problem I started by removing the housing of the Bluetooth music receiver after soldering a wire to its ground and fifoota pin I hooked it up to five foot power to find out that it still works fine and that my smartphone can connect to it now at this point we obviously need the amplifier from back then but since I could no longer find it anywhere I was pretty much forced to gather all the required components and start building a second amplifier based on the schematic and created back in the days and after around two hours of soldering the amplifier was complete and does not blow up when powering its with 12 volts perfect as the first tests I cut up a 3.5 millimeter audio cable in order to expose its three wiris after determining that the blue wire was grounds isola dates to the ground of the amplifier boards and afterwards I soldered the left and right channel to the amp inputs now after hooking up a speaker to the amp and the audio cable to my phone you can hear that the audio amplification works just fine and that there are no buzzing or interference noises whatsoever so next I used to fight fools linear regulator to step down the mandatory 12 volts amplifier voltage to 5 volts this way I can hook up the Bluetooth music receiver to the same power source and as you can see it works without any problems but as soon as I connected the audio cable you can clearly hear the interference sounds I was talking about early on so where do they come from to find that outs I firstly had a look at the waveform of the sound which looks something like this and is characterized by reoccurring pulses next I hooked up a 1 on current shunt in serious to the Bluetooth receivers power line and had a look at the voltage across it as you can see the current reporters of the reciever look pretty similar to the interference sounds we are experiencing so in conclusion that means that the receivers current draw is what is causing the unwanted noises and you can hear them since the amplifier as well as the Bluetooth receiver shall be same ground potential simplified speaking that means noise gets injected into the audio signal ground as well as the amplifiers ground and there is something we have to change in order to get rid of the buzzing but before finding proper solutions to this problem I want to prove that my empty sign is not the reason for this problem that is why I hooked up all of the components and signals to a premade amplifier ports based around the PA m8 406 ICU and as you can once again hear the interference problems to still exists but are a bit less horrible because this PCB design is way more optimized than my crude perfect soldering design so the first proper solution to this problem is like earlier mentioned by using two mains power supplies this way there's only a ground connection through the audio cable but all the noise trading currents are kept away from the amplifier because the power grounds are isolated from one another I actually built up such a two mains power supply circuits once again in order to let you hear that it truly does solve the problem the next solution is to use an amplifier ports which comes with a ground pin and then a ground or analog ground pin which are isolated from one another like with this TPA a 3 100 t2 amplifier ports this way by hooking up the audio signal ground to a ground and the power ground to ground we can keep most of the power noise away from the audio signal and as you can hear it drastically reduces the interference noises because of this solution you might think that isolating the audio ground from the power ground would always be the best solution and that is what the comment section underneath my videos and I thought as well that is why the third and supposedly best solution should be a ground loop isolator that sits in between the Bluetooth audio signal and the amplifier inputs and isolates the grounds from one another so I got myself such a ground loop isolator which after tearing it open later basically consists of two transformers which like already mentioned create a galvanic isolation between the inputs and outputs and after placing it in between the Bluetooth outputs and the amp inputs we can hear that it pretty much changes nothing when it comes to the interference noises so sadly I was wrong with this solution and we should focus more on creating a separate power ground for both devices and that brings us to the last solution which is a DC to DC converter suited for isolating DC power rails by simply placing it in serious to the fifl power line of the Bluetooth receiver we isolated its power ground from the amps power grounds and thus once again achieved pretty much the same effects two mains adapters would have achieved only at a smaller budgets and of course if you're using battery power then two mains adapters would not be possible and you would have to use this solution as a replacement and as you can hear the interference sounds are gone with this solution and I hope that you learned a thing or two through this video and maybe even use some of its ideas in your own upcoming projects as always thanks for watching don't forget to Like share subscribe and hitting the notification Bell stay creative and I will see you next time