How to remove buzzing/noise from a cheap Bluetooth Music Receiver? (Experiment)
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In this video I will be having a look at the buzzing/noise problem that cheap bluetooth music receiver can create. I faced this problem in a previous video of mine but used an easy fix to get around it. But this time we will find out why a buzzing problem can occur and how we can fix it. Let's get started!
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Music:
2011 Lookalike by Bartlebeats
(incompetech.com)
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
It kinda hurt when you clipped that 3.5mm's cable so close to the connector.
Ya
Ya
ikr
u can always reuse the jack if u get that plastic off but it would be simpler to just leave some wire
That was such a low en cable that you wouldnt want to use the connector anyway.
GreatScott: Doesn't say *Let's get started*
Me: WHO ARE YOU AND WHAT DID YOU DO WITH SCOTT?!
I am sorry :-( It just did not fit.
Lol
Actually, his name is Jeremy.
@@greatscottlab no problem xD
I thought "Lets find out" was a reasonable substitution for "Lets get started" considering the video`explicitly states "(Experiment)". Though we could have done without the "in this video".
First of all thank you for discovering such a problem. I've been suffered with this problem for a long time. Finally you revealed it. It was such a great demonstration with diagnosing & resolving. I think it's a prefect solution for those noises & it's pretty easy to solve it. Keep rocking Scott, stay creative 😉
I built a mic and amp circuit from a salvaged electret mic from a cheap headset and a LM386 as an amp. 3 volt coin cell for the mic and 9v batt for the amp, with gain and volume controls. Whenever I turned the gain or vol up, terrible hum, like a horn. I could see the oscillation on the scope. Separating the grounds fixed the problem. Now I can use it to hear previously undetectable air leaks. THANK YOU for the solution to the problem !!
Two notes from somebody who has used these little all-in-one isolated 1W or 2W power supply modules in projects before:
-These devices are typically *unregulated* (including the specific one shown here), meaning that especially at very light loads, their output voltage can be substantially above the rated 5V and they will vary dramatically depending on the load current.
-The power supplies usually have very high idle power consumption (5-20mA is typical) and also low conversion efficiency at low load. This makes them quite unsuitable for battery powered applications unless you can shut the converter off completely during idle times and your active circuit power is well above the idle consumption of the converter.
Check the datasheets carefully before specifying one of these in a design - most of the graphs sneakily only show efficiency/regulation starting from 10%-20% of rated load, and their behaviour is *much* worse below those points! For light loads, this can be a big issue.
For some reason when using one of these its introduces somewhat a static hiss into my Bluetooth receiver and I do not know why? Any ideas ? Any help would be greatly appreciated.
@@rashad5286 a little late but put about 5k resistor in parallel to the isolated converter's output to create a light load, so the voltage is stable. Without this your bluetooth connection could break when no music is played due to the voltage unstabilities.
Any other issue you're encountering such as hissing are due to your receiver itself and you can verify this by powering it with another battery.
Noise is the bane of audio projects, thanks my dude.
Two other areas you could look into are: a lower impedance ground between amp and receiver as well as better supply decoupling on the output of the 5v regulator. The decoupling network needs to take into consideration the frequency content of the receiver in order to decouple successfully.
this video gave me the solution , that i was looking for over an year ..
i am not an electrical expert , but i also did build my own music system and faced this problem .. and after a year later .. now.. i found the solution here
THANKS
I powered my Samsung 10" tablet that I integrated in to my car by wiring directly to the car's cigarette lighter power feed, however, this created this same ground loop effect. I overcame that by buying a hefty 12v > 5v DC/DC isolating converter, but it was quite expensive, as I wanted it to be quite a high Amp rating in order to charge the tablet whilst using it. Great video!!
Oh man you’re a master, you produce videos of all the questions I used to have some years back and never had an answer to
The 1:1 transformer in between the audio did not work as the two grounds were still connected. If the 1:1 transformer was used two separate the grounds it would work, however, you of course can not do that with DC so you have to use a switching converter. This is precisely what the DCDC converter is; a transformer with switching power supply. I think it would have been good if you would have mentioned this in the video.
Correct me if im wrong but in the 1:1 isolation transformers grounds are not connected. Isolation transformers can filter out DC interference voltages. The interference that we saw in the osciloscope was actually an oscillation that via induction was created in the secondary winding of the transformers there.
If you ask me, biggest mistake in this video is that he forgot to mention "the" solution - proper star ground connection
I searched the whole internet for this before with no suitable results! Thanks!
Excellent solution. You can also measure the voltage between the 5V negative rail of the receiver and the 3.5mm ground, when thereceiver is powered on. In my case (slight different receiver board) I measured a 3.3V difference between the 2 "grounds", that definitely means the receiver need a galvanic 5V separate source.
I had the same problem. And I tried the same methods and stayed at DC/DC converter, the best method. I really didn't realize what the problem is, if the amplifier and the bluetooth receiver have the same grounding, thanks for the explanation GreatScott xD
I was just making this as part of a college project and stumbled upon the same problem. Thanks a lot Great Scott, it's like you read my mind.
He is the best
Wow the exact same thing happened with my friend!
@@wasaybaig1519 XD
Lol
DC to DC isolator is the best of the best solution for diy amplifier projects. It helped me removing the buzz noise!
Literal i need this 4 hours ago 😂
I love you baby marry me
Same here
Well I found a simpler solution that worked for me.
A) Find the feed of the 12V to your amplifier and connect there. Don't use the PCB traces closest to the amplifier IC. Instead get closest to the power supply feed.
B) Use thick wires to feed the LM7805 regulator! This makes all the difference. Don't use wire (single copper conductor). Use thick cable (many conductors). For me 16 AWG eliminates all the noise. After your linear regulator IC you can use smaller cable.
You know what i find most interesting in this video? Your amplifier. It uses an unbiased output stage where you're simply forcing the opamp to slew right over the required approx 1V bias voltage gap of the output transistors, and to somewhat smooth out the resulting switching atrocity, you have a feed forward resistor. This is actually kinda cool. According to my simulation, not quite hi-fi, but cool.
i love those tiny DC to DC modules, they are so freaking handy.
Yeah
But they waste energy
@@ProtoMan137 ist egal
I have the same problem, and i really struggled to find a soloution for this. Thank you really much for explaining this problem and showing some soloutions! It kinda saved my day.
Not to long ago I was looking for this exact solution but no video could resolve my issue, but I'm glad you have made a video about it.
The ground loop isolator is used when your amp and source are on separate connections
The point of it is to stop one device using the other as a ground.
Additionally a ground loop is characterised by a 50 or 60 Hz continuous humm, the fact that it has a repetitive load (likely when the Bluetooth is transmitting it's beacon) shows it is not a ground loop
A lot of that noise can be removed by adding extra capacitance to the power supply rails for the bluetooth device, along with making it the common ground point for the project, so that the long cables to the input are not adding resistance to the ground path. 220uF 10V capacitor directly across the 5V pins into the unit will improve performance a lot, as the regulator output impedance rises with frequency, they are not good at reducing high frequency noise, you need low ESR capacitors near the load to do that.
I've thought that he will teatch how to remove the: "butu dewice ready to pail" sound when u turn on any speaker
Someone should create/sell a mod kit that mutes the speaker for like 2 seconds when it's powered on or something, tho a better solution probably exists
Exactly what i was thinking.. i was a bit disappointed lol
Lmao ikr i hate that fucking sound so much 😂
@@shutdahellup69420 They say its programmed via computers.
you forgot : 'the butu dewice iss connectedya succesffulaay"
Why didn't you say "let's get started"? You're not Scott, I need answers
I just did not fit this time. Sorry. Next time.
@@greatscottlab let's find out could have been replaced 😁
"Lets find out, in this video." 0:52
Scott but not Great
I often do skip the intro music on channels but not yours. Love that music
I enjoy even the way that Scott writes (left handed).
3:19 Scott: "So where do they come from?"
Me: _No._
My Brain: "Where did they go?! Where did they come from, Cotton-Eyed-Joe!"
Me: *NOOOO*
Go for the eyes boo!
So wish l had your knowledge and Time as l'm getting a little old now going for 67 in couple of days.
Still l enjoy to see you solve problems for so many , thank you for sharing.
this problem bust my ass for 7 years on every project and even electronic teachers tell me use two battery on adaptors thank you manso so much
What if you put some inductors in series to the power lines and some caps in parallel?
I though the same thing
Me three. If the spikes are caused by a current spike/drop the best thing might be to simply add a buffer cap. Not sure about the inductor though, at these low frequencies I have some doubts whether that would work, this is usually done for high frequency filtering.
I always do that back then.Just solder 2500 microfarad 16v capacitor parallel to the supply wires in the Bluetooth module.
@@danielegger6460 Inductor is for the back emf so just to create a local emi/c condition. Much like a diode or small value resistor before the converter to create a smaller loop area. any noise from the local supply is dropped to ground.
Have you tried it? Maybe lifting the ground from the BLE end shielding?
Great scott: I couldn't find the amp
Me: LOOK ON YOUR CEILING
Most interesting, many thanks, stopped me from chasing red herrings and focus on the simple fact that the noise comes from the power rail. This led me to a simple fix ... Starting with an existing power amp with a single rail 20V supply I used a 7905 to create a ground that is 5V below the positive rail. This creates a split supply to power my op amp based front end. The op amp doesn't care that the rails are asymmetric +5V and -15V. The Bluetooth audio module powered from the +5V rail produced a massive amount of noise but a 5mH inductor (a few windings on a toroid core,
Most of people who working in audio industries are in trouble due to interference noise in their audio system but your idea to isolate ground with DC to DC Converter is awesome
I recently research on this problem . I found that there is problem in bluetooth receiver ground ( no proper thickness of track ) so it do not allow proper flow of current so i connect ic ground with a wire with main ground with additional wire. (very very very very cheap solution)
Hmmmm I did not try that.
@@greatscottlab pin this post!
Good to know. Will try it.
Tried adding an additional ground in my car and it did not work
It work
Thank you so much for making this video
I was facing the same problem when I hooked up the receiver to my cars basic music system. Now I will be able to smack down the interference noises.
Keep it up👍👌
This guy and diy perks complete each other
@GreatScott! Man i bought the exact same Bluetooth module 2 years ago and never managed to get around this buzzing noise. I can now finally finish building my diy bluetooth speaker, thanks so much❤
BT audio out GND joins the power ground of the amp board and creates a loop, also your daisy chain ground system is "no no" for audio / analog designs. Use a star ground configuration to a low impedance point like a main filter cap and interrupt the loop created by BT aout GND. Potentially I'd try to connect BT aout GND via 100n cap to non-inverting input of your amp ( pin3) to run the amp in differential mode. 12V/2 DC bias circuit should be bypassed by a cap and then brought to pin 3 via serial resistor eg 10k. Sure there are more options, but DC-DC isolation for such a basic circuit is an overkill.
You should give your completed schematics in the end of the video or the description, so if we ever want to attempt such a test we can see where exactly the change occured.
Btw, YOU ARE AWESOME DUDE. I mean it.
Scott, you did the fix with the DC DC converter, but didn't explain the part or part number (handwriting looks like B05055 instead of S) and instead linked products in the description that weren't used, without linking any examples of what to actually use. I appreciate the help solving my problem! But you did all this work to still have viewers going down a rabbit hole of research to figure out what to buy!
In a project i had the same problem as you and this solution comes to be the best one. Thanks a lot!!!
Usually i just solved this by disconnecting the audio ground. Quick and dirty but it worked.
Theres no noise if there is no audio!
This is a good answer, as the ground is common, there is no need to introduce a ground loop. It's also important to use buffer and filter capacitors near the consumer (in this case near the bt receiver AND near the amp).
Works well for the XS 3868 tbh
@@dusinnhht what capacity would you recommend?
HERE IN NICARAGUA WE CANT DO IT EASY BUT I WILL thanks to the master Greats
Add some bypass capacitors across R1,R2 to to decouple your amplifier's virtual ground (pin3) from supply fluctuations. If you use the isolation transformers then you can connect your input signal ground to this point as well.
Boi i've been having the same problems, I tried to connect two different amps together to form a bigger amp with a separate line for smaller speakers. And i got a crazy buzzy noise. I just gave up on that project because there was nothing i can do. I will try the DC/DC converter method. I just hope its available here at my local stores. Thanks for making this video mate!
As a person with electronics background I really enjoy you videos man. Keep up the good work!
Thank you greatt scott i learn a lot waching all your videos
Keep up the good work👍
You're welcome and thank you :-)
You solved one of the reason's for the annoying white noise mate... 🍻
funny that i did this experiment last year when adding BT OVCxxxx module to my car stereo's tape deck preamp output. Isolation transformers were a nogo but i remembered that i had some of those isolated DC-DC converters and it was perfect. I ended up using an ATtiny to monitor the tape deck motor outputs to simulate the encoder signals and give the bt module the ability to skip and prev songs using the OEM controls.
Shows an ad for JLC PCB... *Doesn't use a pcb for doing this and uses something else*
Many promote VPN services but never use them on videos. It might have something to do with the target audience.
What he is doing here is prototyping, you don't manufacture PCB's for prototypes.... If he was making a finished design with an enclosure etc then you would make a PCB since you have a circuit you know works.
You can get sponsored and promote things without actually using them?
@@yeet1337 yeah... but what i said was a joke
@@yeet1337 I've understood the sponsors just send an email they'd be wishing to promote their product.
Hey Scott! I used this same technique in my creative desktop speaker pair a year earlier and it works great. Thanks for shedding some light on this matter. Nice job man! 👍
Helpful information. I like your video
This video is super useful for my factory radio bluetooth mod (Added bluetooth to my cars factory head unit).
Good topic for proff audio stuff. Ground is always important.
Thanks Greatscott, I would need ground isolation for my school's buggy project where there are sensor, motor, and control subsystems involved.
Brilliant video ! If i only had it a couple of years ago ! had the same problem and ended up using 2 mains supplies.
Disconnect the audio ground from the amp input and use a thick, short piece of copper wire to link the BT and amp grounds together. Connecting BT power ground and BT Audio ground together creates a ground loop! Additionally add a lowpass filter with 22ohm resistor and 1000uF capacitor before the 5v regulator to dampen the current spikes.
Was going to convert an old boom box into a Bluetooth one. Thanks for telling me about this issue I was going to face.
Common mode noise is a real bugger sometimes. DC isolation is the go to fix for it although sometimes it can be eliminated (or at least sufficiently attenuated) in the IF stage with ferrite beads or an RF choke coil. If you were dealing with radar frequencies even PCB foil trace placement and pathways are a solution.
Thank you for going through all the effort of building up every possible solution just to educate us. Have a nice weekend.
I just searched for that and 3 days later GreatScott loaded up a video
Pick a 5V regulator that has an extended PSRR frequency range. Like the Texas Instruments TPS7A4901 (also comes in negative polarity versions if you need it). I use these to power highly sensitive, load cell signal processing circuits. Be sure to use ferrite beads and common mode chokes on the input to the 5V regulator.
Also consider that the Bluetooth receiver may not meet FCC-B. Try separating the Bluetooth receiver from the other audio equipment.
What about disconnecting the audio ground from one end (receiver)
It's common that the main part of an audio system is the hub of all grounds, anything remote that is powered from the same supply uses the supply ground, with the audio ground disconnected, but in the case of a sceeened cable the screen is connected to the amplifier only
Power grounds would still be connected, so audio inputs would use that as audio ground.
Correct, but it's only one ground, not the 'hum loop' that i think is causing the problem
@@sparkyprojects this isnt a hum loop, its oscillating from feedback. What probably more likely happening is the power sugres in the audio amp are affecting the bluetooth ground, causing a feedback loop
@@researchandbuild1751 As far as I see it, there is no feedback, just big enough load-pulses from the bluetooth module to create a voltage shift on amp-ground vs bluetooth module-ground.
The fix is probably isolation, or really good ground connection (like soldering the board directly to amp-ground without wires using a solid connection). Analog ground/differential inputs amplifier should also do the trick.
Adding capacitors to power input of the bluetooth module itself may also help.
The best place to kill off noise is usually at the source rather than at the receiver. It's clear that your amplifier needs much better decoupling. This will reduce the output noise and improve the amplifier performance...
I wish you had shown a clear view of the bottom of the isolator that you took apart so that we can see how it was made. We can guess how it was hooked up, but it's nice to be able to see how traces connected the components.
Your solution with the different power supplies seems to work for my case where I wanted to connect a TDA7498 with a seperate bluettoh module... Thanks!
Thanks I used one of those DC DC things in the past and it works greats. There is always some smartass always telling you that you did somethig wrong in the amp or to put capacitors in stupid places. 99% of DIY BT speaker like this have this problem.
Put the negative end of a large capacitor directly to the ground pin of every chip and the positive end to the power. This worked for me.
Of course block capacity should be part of your design, how should this work to avoid ground loops?
@@patrick_test123 You can call it whatever you want but this Worked for me at reducing the buzzing to a hardly noticeable level.
Also, the AGND (the audio ground for left and right) is connected to the common power ground for the Bluetooth receiver module from the manufacturer. It is the same scenario on the amplifier.
Well that's great. Your are my inspiration sir. From your video my interest on eletronics multiplies more and more. Love from india sir.😇🙌
Greatscott: let‘s find out in this video!
Me: huh ? Who are you
One can also use a 12v to 5v 1W DC-DC converter and eliminate the 5v regulator. The B1205S.
I love your drawing skill
great i was looking for this type of video thankyou man
THANK YOU so much
and as always amazing video
You're welcome :-)
@@greatscottlab :-)
exactly what i was looking for!! thats crazy!! im gonna make a portable diy blueth speaker! thanks!!
Cheap small speakers are less prone to these noise problems , so one can get away with common supply to both Bluetooth and class D amps like PAM 8403. For Good quality high sensitivity speakers I find using seperate 5V SMPS like mobile chargers(everybody has atleast a dozen in attic) much more effective solution.
Wish I saw this video a week ago. I fixed a modeling guitar amp for a guy in my area and had this issue. I messed with chokes and filter caps all over the show and eventually returned the amp to it's owner. In your signal, I can clearly hear mains hum. In mine it was mains hum then a high pitch on top of that. Kind of like mains hum becoming the high pitch sound as capacitors filled up. Wish I had more time to figure it out.
Cant you put a capacitor in paralell on the 5V line, so that it smoothes out the interfierance?
I tried by myself. doesn't work.
@@SyazwanSaidan Maybe some higher capacity capacitors.
If you added it in series you would form an open circuit as soon as it charged.
@@AtlasReburdened This happens with direct current since the voltage is constant, but rember that an audio signal (and any type of signal) isn't constant. A capacitor put in series between a signal and an aplifier is actually used to remove offset voltage.
@@AtlasReburdened Yeah i ment parralel
Hey,
I can't look through all of these comments, but it seems you could use an opamp for ground isolation. Put say, a 100 ohm resistor between the grounds and use the opamp as a common mode isolator.
It's what I would use rather than a transformer.
Great video man... Helped me to solve the problem I was facing
Deep and clear info
You are my all time favourite.
Thank you very much :-)
was just suffering from the same problem. thanks a lott,
my friend great scott.
Thanks so much, I'll try with this DC-DC converter, greetings from Mexico :D
Been looking for a solution for this problem. Thanks for making a video.
I solve this problem by using just one single cable for ground on the bluetooth module, and one single cable for ground on the amplifier, but this cable must be short and very thick, connected to the power supply, And the noises almost dissapear, another solution is to insolate the ground feedback of the amplifier (the gain loop) so it became a kind of diferential amplifier with common mode rejection. That helps a lot, and using both of them you will not hear the noises.
wow man... this looks amazing and promosing... i have ground loop problem in my car with BT and phone adapter charger in 12V port
Just add a series 10 ohm resistor to module vcc input and a 220uF bypass capacitor between vcc and gnd. That removes most of the audible noise.
i used a dc to dc isolator too when i worked on my diy bluetooth speaker. worked perfectly
hey bro i noticed on cheap mouses that there are empty places on the pcb where there should be components but there arent. can you do a comparison to see if you complete the empty spots if it brings a difference or not.
Have you also tried to remove/modify the action sounds? Like “The bluetooth device is ready to pair” or “Phone connected”
Those are annoying as f
Every chinese device needs to speak, but WHY??????
@@fusseldieb Because chinese like "Fashion Sound"
Some times there is a programmed function to turn these off... like holding down the pair button or the play button or something.
@@adrigenvongarnerd i managed to reflash the flash ic to remove the sounds... as you can see in my video
I wish I could isolate my grounds and remove my tinnitus :(
Is it already soldered in place? You could just scrap it and start over if your project is that botched.
@@Allocated_Brain Maybe I'm.just not getting the joke, but OP has tinnitus, a hearing issue which causes annoying fake tones to be heard when the sufferer is in silence.
@@aathish04 The joke is that OP as the 'project' is faulty at a fundamental level requiring a whole replacement unit.
It's 2020 and still no cure. It should be the future damn it!
It's being worked on. They've already figured a way to "reflow" the "pcb" to fix bad connections between components so right now it's just a matter of looking at the diagram to figure out where to point the inductive antenna.
rTMS is a helluva thing, it's going to be BIG in the 2020's.
Nice solution. Love your work. Keep up the good work.
I was contemplating removing the logic from my Soundbar and replacing with my own setup similar to this (ideally retaining buttons and inputs). I may have to open it up and inspect it. It's a decent soundbar, but I don't like some of it's behavior (# of volume steps, auto-off delay, etc.).
I have got rid of the noise by disconnecting audio ground at the bluetooth receiver end. I didnt have high hopes but it is working for me.
Thanks for the informative video! You fixed my noisey Bluetooth speaker build!
In principal, a proper LC filter, (note, not simply a capacitor) should do the trick with something like this, if spec'ed properly for the interference in question.
I wonder how much a simple inductor would help, just to resist changes in current
thanks for this vid,, got a solution for my mini mixer audio project … god bless bro!
If I remind correctly, the easiest solution is just a pair of resistors in parralel with amplifier input. The reason is that amp has a very high-ohm input, so it catches any interference. Resistors will gischarge any interference (irregardless of it's nature), but won't really affect signal.
I may be wrong, i'm not 100% sure. But I suggest try, then critique. Resistors could be somwhere in ballpark or hundreds ro thousands ohms.
im going to try this, maybe this can solve the problem. the converter dc-dc not work for me, this thing give me more problems than when i dont use it.