STOP hum and buzz in your amplifier projects !
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- Опубликовано: 15 мар 2017
- "Help! My audio amplifier project makes a buzzing noise when I turn it on." This is the most common question I get. I decided to make a quick video to answer this question. I covered the topic at length in this video:
• Correcting hum, buzz o...
How to add a volume control:
• How to add a volume co...
Thanks guys! I appreciate your support. -JAT 
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Hi all. I used 100ohm resistors with my good old Creative SBS A220 speakers and succeeded. Noise is gone. Also that did not make any adverse effects on sound quality when I connected my phone to my speakers. Also thank you very much John for this video.
Hey, Did you connect a single resistor? In between ground of input or input channel? 🤔
No it does not work. It just lower you hum and audio signal. But still buzz
Thank you, you have just saved me a lot of time and frustration. I can turn up my LM4780 to max now and with my ear pressed right against the speaker I can only hear the faintest hint of a hum :)
Bro sounds like Tobey maguire😭
Lol wtf bro?😅
Great video... we need more like this to help the average techie! Good work
love your videos sir! amplifiers are one of my hobbies so all of this is very interesting and teaching
Commonly, there are two kind of noise in computer PC: ground loop noise (only if you have different grounds connected) and picking up noise signal from audio cable. For ground loop suppression, just buy ground loop suppressor (basically just using transformer). For noise picked from audio cable, you can shield/wrap your audio cable with aluminium foil and connect that aluminium to ground, works for me.
Yeah my little wall mount amp will be used for PC and Casio keyboard audio(it is essentially a PC speaker system without the PC speakers , so just the internal amp mounted on a decora faceplate in a switch wall box). I have all the connections ready but there is a 3 pin input terminal that does LEFT, RIGHT and GRD. I have shielded twisted pair Cat5e cable.. no pro audio cables at all. So what is your suggestion to keep possible PA amp hum at bay there?(this also has a mic input just like in a PA pager system).
Hello, I was wondering if cable lengh matter and were to pick the shield if using 3.5 mm audio jack? Regards
What if it is just noise? I dont connected to any cable but it still noise, buzz
Thank you for this! I had to put a 2 resistors, one to ground + left and one to ground + right in order to get both channels silenced... got rid of buzzing by 90%
Please help me out. +233570306 on WhatsApp
How exactly you add resistor with channel + ground? 🤔
It works but audio quality/volume get reduced
@@KausikKumaar in my case audio quality got better
@@captainjim1010 ok maybe i am using low resistance will try increasing to 10k
Hey everyone! Thanks for the views. My first video with over 1K views in under 20 hours. Also, a big thanks to those who answered questions left here in the comments. I can't do it all myself.
I really enjoy your videos! Thanks for sparking my interest for building amps, it's a very rewarding hobby! :D Keep up the good work!
JohnAudioTech Hi ..I'm a new subscriber love your videos man..so my question its I'm going to build a custom boombox with a TDA amplifier its says 100w x 2 do you have some video where I can learn how to do this?
John I purchased a 750 watt ever start inverter, I hooked it to a marine battery, whenever I plug my guitar amplifier and pa system into the inver, a lot of static hum starts, but when I pick my guitar up, quite a bit of the hum leaves but is still there, without getting technical please tell me what I can do to fix it.
Hi, just saw this page: antiqueradio.org/recap.htm and wanted to question: is it possible to wire an electrolytic backward and have this kind of "hum" in modern sound systems?
1:18 How Dubstep beat drop be like...
Thank you for narrating. Truly.
This was a nice, simple demonstration of how to potentially kill the ground loop noise in the AUX input in my car. Have to try it out this weekend before I buy a more expensive option.
Did it worked for you bro?
Simple solution yet effective, thanks.
Use a small board with the BA3121 it will cancel out lots of distortion caused by ground loop.
It uses CMR characteristics of the opamp.
Just to clarify, you might show what that install looks like on a typical amp board (e.g., parts express) with stereo input. Very helpful video. Thx!
I have just had a look at my crap system in sunroom. Had bad hum the cheap player had no bass and no controls.
So I plugged in a scrap amp , got the tone but also got hum . Now put 1k across both inputs and fixed. I was looking for a hum loop.
Many thanks.
you save my life, John
It works man, i was facing the same probleme. thanks a lot.
Great video - thank you John!
Yeah it's really work! Thank you. 👍🏼
I was looking for something like this ...I will try your trick . Thanks !
Thanks for your recomendations
Thanks , it help me a lot, I was tired of shitty noise :)
its workinggg. thank youuuuu
woo, that was easy, thanks John!!!
Great fix.It really helped. Thanks bro..
Help me, use resistor between R n L input or R to G?
thank you so much ! you help me with this video .
How Dubstep was Discovered XD 1:18
Lol
very helpful, thanks for the video
Did adding the resister also shunt the feedback when touching the capacitor?
Another way is to use an isolation transformer on the audio or use a larger filter capacitor on the power supply.
Where should the audio transformer be placed? In the audio input or output?
@@diypasstime7785 Input.
Hi John. Great Vid.
I get the same hum albeit Louder off my Adcom as soon as I turn it on. I did accidentally drop the unit within a box on its side 3ft off the ground.
Do you think I may have damaged the caps or need to resolder some points which may have come loose?
I'll have to try this on my little mono class-d subwoofer amp in my boat =)
Thank u nice explanation
i got a long 5 meter headphone extension cable but it is next to power wire and it hums a lot and when i plug in headphones it pops loud.
Nice Video ! Truly fix the noise mostly.
Very powerful video
good video and thank you so much
So my 5.1 amp Stereo is 7294 ic dual sub irfp150mosfet surround is tda2030 4 ic centere is tda 2030 2 ic ....i have this small noise issue....Which resisters use to reduce noice? ...i am also use shielded cables for all inputs to volume control and amplifier ...
Thank you!♥️
I builded lots of amplifier with Lm4780 / lm3886 / tda7293 and many class A with always the same humm noise trouble ! I try your tips about 1K resistor between the gnd and signal input that help to reduce but not gone at 100% do you have another tips for build a truly silent amplifier ? thanks in advance ! :)
That was especially worthwhile John....
So I have a TPA3116D2 Dual Channel class D amplifier board and I'm using it with a separate Bluetooth amplifier and when Bluetooth is turned it makes like a 5k hz noise but when I'm using aux through the Bluetooth amplifier it doesn't make any sound. And I've tried the Bluetooth amplifier on another amplifier but it doesn't make any sound when Bluetooth is connected, what could be wrong?
Thank you from Algeria!
can I add a resistor in the input if I want to amplify a mic level signal from a microphone. I bought a cheap PA system which outputs too much noise, even when using the wireless mic or when connected to bluetooth as a bluetooth speaker
wow that shrieking sound is awesome tho, i might want that to be a pedal effect for my guitar
Thanks for sharing sir
Awesome fix! It worked in eliminating the irritating hum from my DIY subwoofer amp.
As I built the normal stereo power amp first, and then this subwoofer amp, I will have to do the same on the stereo inputs on the main amp?
Can this be reduced to one single resistor on the initial input, which is the headphone out from my computer instead of three resistors, one for subwoofer amp's mono-fied input, and the two separate left/right inputs on the main amp board? :/
That sound when he touched the capacitor 😂
that's a cover. someone?
I cant open my current speaker set up(atleast not without breaking it). Are there thing i can to the 3,5mm to improve it? Like an adapter or something
Thats what i wanted to know!
Thanks for upload!
Will this work on PAM8403 amplifier. If yes then what is the resistor value will be?
So how can we do this with the class D aliexpress amps? Not sure where to look on where to put the resistor over the input.
Hey john, can we use this at each stages, like before preamp, before poweramp etc.
I have a mini arcade cabinet box with a PI, LCD screen, joystick driver, and small mono amp in it. The speaker is giving this type of hum and is also picking up interference from the pi. The audio cable from the PI to the AMP is already shielded. Would a simple resistor solution work for this, or do i need to shield ether the PI, the AMP or both? It running retro pi in the case, and apart from the audio buzz it's all running quite well. Apart from the buzz the sound level range from the AMP is fine.
The last images in the end was like the berry on the top of icecream :D
Hello, I have that horrible noise I connect my turntable to a pre-phono in and out to a sansui amplifier on tape, even if I plugged in the ground wire that horrible sound follows, what can I do
Hi John,, Thanks for the great video,, I was wondering what amplifier chip your using in the video and what current and voltage your supplying the chip with,, Sounds Great.. I Still haven't received my PAM8403's from china yet,, boy it sure take a long time,,
Damgoo audio boards have been good for me get the 5 knobber built in xover
When you say "across amplifier input", does that mean, i connect both ends of the resistor to the negative and positive of the input? So if I have a stereo input, then I should put on both channels? Connecting the left channel to the ground, and right channel to the ground as well?
Like this: L-(1Kohm)-G-(1Kohm)-R
Nice. Very Good.
what resistor value I'm going to use if guitar to amp? any suggestion value of ohms
This works because you are shorting part of the input into ground through resistor, which makes you amplify less noise. However you also amplify less input, what means that you just lowered the volume. If this was a "simple and no-loss solution" each and every datasheet for an amplifier would included this input resistor as a default part. This obviously is not the case.
What you can do as a "lossless" solution is to use special input jacks, which when there is nothing connected to the input short inputs to ground. This causes no hum when nothing is connected and no loss when you actually connect something. You can easily check there is no hum for almost any amp when you connect input connection to ground. Many guitar amp input connectors have this, this is why when you do not connect a cable to the input there is no hum and when you connect one without a guitar at the other end the hum is there and effect is the same as in the video.
There are also other factors like cable shielding (especially with very high gain amps), how ground is laid out in the amp circuit, filtering etc. Overall I would not recommend this, since you are removing hum, by lowering the volume, which does not make much sense...
XaFFaX.tk I don't notice any difference between the input with or without resistor, even if I put it while playing. However I have to use a 200ohm resistor to remove the noise, could that damage the input? With an higher resistance the noise remain the same
I don't understand the thumbs ups. Maybe you have to dive into the depth of electrons, electrons flow to the path with the lowest resistance. I think you did it wrong by placing the resistor in serie and not parallel, in serie you are right (lower the input by resistance), in parallel you are wrong. The resistor in parallel avoids a floating state (not connected) and acts actually as a pull-down resistor, it simulate something is connected. In fact it stabalize the floating state and suppress noise. 10k is very common because there are also 10k pots. When you connect a source with only a resistance, lets say 300 ohms, the electrons take that route. I think you connect it the wrong way.
yes you're right it's just a pull-down resistor and it'll work for most cases to avoid a floating state
His solution is 100% valid. If you use a high value resistor like 1meg ohm, it actually can help "short" EM interference to ground by forming a non-floating state. Meaning the amplifier will stop picking up "RF" EM noise. And in fact it is a recommended practice to never leave high gain inputs floating.
Since the resistor is a high value, it will have little effect on any normal input signal since those signals are much larger than the noise EM signal.
This video is perfectly accurate and is a valid solution. It's not going to cut the gain down hardly at all.
This pulls down the floating voltage. It isn't just reducing the volume. The noise is of MUCH less current than the actual input, and this works to filter off the low current voltage overlapping the signal. That isn't the same as lowering the volume.
On the other side of the input is a buffer which will compensate for your resistor to ground. There is nothing compensating for the noise getting dumped to ground.
so i have this issue, when i turn up the volume at 50%, the noise from the tweeter and my woofer so high, but when i put the volume to 100%, the noise gone, can you explain why ?, i'm using cheap class D amplifier made in china, using the TPA3116 chip, with 2X50W channel
Seraph I have the same problem all the time with a bunch of different amplifiers and I haven’t found an answer for that.
nice tip !!!
tthnks very very much
i have a power amp and when i low the volume the sound is not clear bt when i increase the volume it fine sound.what i will do sir hel me please.. create a video on this..
Hello, Boss
I saw impedance plug on amazon, will it useful to reduce hum noise?
What hms should I choose? Thanks a lot.
Hello, thanks for sharing this video. I have an lm386 guitar amp. The noise comes with nothing connected. I have connected the 1 k resistor as you suggest here, and the noise goes out, like in the video, but with the guitar, affects the volume. So, I have two questions:
Does it happen the same attenuation to you, with your earphones out? Have you checked this?
And when you talk about shielding, do you mean to use a shielded guitar cable, shield the electronics of the guitar, or both things
Guitars need high impedance inputs, so the 1k resistor will shunt too much of its signal to ground. You should try a higher value. Shielding the cable and electronics as much as possible can reduce noise.
@@JohnAudioTech I have tried with a 104 capacitor and it reduces noise volume as well. It seems that the volume of the signal for a guitar does not decrease too much. And it is more clean...
what cap can add to remove noise from an atx fan? in my tda7377?
in high freq listen noise
They have 75 hms to 600 hms impedance plug(3.5mm). May I know which one should I use for my v8 sound card? The wire is about 30 meters long
L'alimentazione è meglio swiching o stabilizzata?
Sir i did what you did but didn't work for my 50watts kit amplifier but can the wire maybe affecting the sound of my amplifier
cause i use a small wire with thin insulator ,and
i use a 12V output charger of portable video player to power up the amplifier- is it not good to use?.
You must use shielded wire for the input signal and ground the shield at one end of the wire.
nice thumbnail you got there sir. :-D
Designer charged 20usd
This is a great video, great explanation! Thanks @JohnAudioT.
I have an issue with an active speaker (B&O BeoLab 8000 with built-in amp). It has an RCA plug for line-in that I want to use. And it has an auto stand-by function which means: the amp & speaker switch on when audio signal is coming in, and it (normally) switches off within 3 minutes after the audio signal has ended.
I have a kind of distortion that causes buzzing noise. The noise is too loud for the amp to switch to off permanently. It does try to switch off, but then immediately switches back on again. This process repeats continuously.
This happens both when I have no external audio source connected to the RCA connector for line-in. As well as when I have an external audio source connected to the line-in. Though the buzz is a little bit less when I plug an iPhone as audio source to the RCA line-in connector.
But even with a source connected to the RCA, there still is a lot of sensitivity. Because when I touch the cable that connects the RCA to the AMP, it immediately switches on again.
Next I connected a 10K resistor across signal input & ground input. Without an audio source connected, it even increased the buzzing noise. With an audio source connected, the resistor makes no difference.
Any ideas/suggestions?
When you say nothing is connected to the RCA line in, you mean the cable is unplugged at the speaker side, right? If so, this could mean an internal issue with the amplifier. If it goes quiet, you are picking up noise along the cable. I'd guess the cable is pretty long.
@@JohnAudioTech Thanks John!
Correct, there is no external audio source connected to the RCA line-in plug. The RCA plug of course is connected internally to the amplifier.
This RCA connector sits on a small PCB and is connected via a 4-pin cable to the amplifier and a circuitry that detects audio signal and switches the power between Stand-by/Off and On. This 4-pin cable is about 15 cm long. If I touch that cable, the amp immediately switches on and the buzz is present. If the amp is on and I then touch the 4-pin cable the buzz gets louder.
Also when I touch the RCA connector on the back at the signal tip (so not ground), the buzzing gets louder and there is cracking noise. Same happens when I touch with a screw driver (I hold the plastic part of the screw driver, not the metal).
I have another BeoLab 8000 speaker; it doesn't have these issues.
Question: do you have any suggestion what next step I should make?
@@KolfMAKER Sounds like an open ground or shield ground. Check continuity with a multimeter if you have one.
Hello all, I built an amp with TDA7297, when signal is connected but paused, and volume at zero, I hear something similar to radio broadcast. Also I have a power switch with lights that lit when power is on, I notice this light gets dim when I touch the enclosure, which is connected to ground. Can anybody give a pointer?
does this work with guitar amps
How can I eliminate noise/static in my house when I turn on the Treadmill, anywhere in house?
Perfect !!!
👍
Your video is the only one so far that has the same EXACT buzzing that I'm hearing coming out of my speakers that I hooked up to my television. They can be used on a tv or computer they used to be on my computer & worked fine. Hooked them up to my tv & the audio works but there is the buzzing (same exact sound in your video here). For the past 3 days have tried all kinds of fixes, all kinds of wires, went to the store & bought different wires, etc. nothing works, constant buzzing. I've heard of something called a ground loop isolator, not sure if that would work but the buzzing is driving me nuts. I can hear audio just fine but during quiet scenes in a show the buzzing is there, I can also hear the same thing you did when I tap my fingers against the end of the prong (the end of the plug)....it did not buzz when it was hooked up to my computer, only when hooked to my tv. Not sure if a ground loop isolator would work, it's my last resort, if the isolator won't work I'm disconnecting them & Putting the speakers back on my tv but I cannot for the life of me figure out how to stop the buzzing, been 3 days now & tried everything I possibly could to no avail.
also I don't have cable television so there's no coaxial cable causing interference or causing the buzzing. I'm clueless at this point.
It could be a ground loop issue if you tried the remedies in the video. If the amp can be powered with a battery as a test (mains isolation) that could narrow it down.
Try turning off all switched mode power supplies in the vicinity (phone chargers, laptop adaptors, computer power supplies, all electronics that plug into the wall).
So just that I'm not wrong. A resistor between the input (+) and GND for each channel?
Same question i had;)
@@Jandejongjong yes
Looks like a resistor between the left and right channel (trs) to me and the ground is yellow. Just my visual observation. Please correct me if wrong.
@@joseveliz6979 No, yellow is the other channel.
@@FacundoAguilera in that case we would hear noise from other chanell that's not resistor crossed ...
I'm having a stranger problem, i have this kind of noise only if I connect an input signal. I've tried everything but it just still here. With 270ohm resistor to ground it goes quiter but on higher volumes very annoying. Anyone any experience about that?
Dang, wish I had seen this 2 months ago. It would have saved me hair pulling on my DIY build.
Hey John. Thanks again for your informative videos. I have a Dayton Audio Bluetooth amp. I think they us TPA3116 chip. There is a bit of background hiss at lower volume. Is there a way to get rid of this without desoldering or changing SMD components on the chip? Would adding a volume control (acting as a resistor) do the trick or am I stuck with it? Cheers
The hiss noise is generated internally (mainly) and there is not much that can be done without making changes to the components.
JohnAudioTech That's what I thought. Thanks for your feedback.
You can simply add two resistor to the jack connector, without making any change to the circuit. There is no need for desoldering or intervention on any smd components. Just use two normal through-hole resistors.
That works for reducing external noise that is received on the amplifier's input. It will not reduce the hiss sound produced by the amplifier itself.
Thats what I thought. Is it something that better circuit design and component selection can fix? It seems that you have reviewed several chip-amps that deal with this issue better then others. Though it seems like many of these D/T Class amps have this problem in some way as you have mentioned. Why is that?
Very nice solution! Simple but effective.
Hey I am getting some buzzing from my amp how do i fix it
What makes the hissing noice in cassette drives can I fix it??
Thanks. I was making a circuit for a guitar on a breadboard. Turns out, I just needed to shorten the antenna. I mean shorten the leads to the output jack. Problem solved.
Why in some audio amplifier boards the value of capacitor at the ripple rejection pin is reduced than specified in the datasheet of that audio IC ?
What will be the effect of it on the amplifier ?
A lower value capacitor would mean lower ripple rejection. However, if the circuit is powered from a battery or a well filtered supply, lower ripple rejection may not be an issue.
IF someone can help me , i have an active amp circuit like this its just Bi amplified rather then stereo, and outputs for tweeter and Bass are shorted , buzz just like this , i dont get it , Tweeter died so i guess that is shorted , but Bass Works , AMP does not burn when i turn it on , without tweeter , There are 3 ICs Power Amps , i changed the tweeter one , but i guess i changed a working part , and There are 2 voltage regulators , changed both of them , changed caps , Rectifying diodes , and when i check output for bass and tweeter , 3 out of 4 wires have a dead short on them , i dont get it why. Im not very good in electronics , but i just changed parts as they are and it didnt burn up , so i guess i did it good , but i have a short and i dodnt know where it is coming from , since most Chips are changed , i didnt chage Bass AMP ICs , there a re2 of them, but if they were shorted , it would burn up , but it Buzzes just liek this on a big speaker so it must be amplifying , so it works , if anyone knows of some Issues that can be the reason for this , im grateful
is this work with usb bluetooth module receiver also? lm given 5v power through 7805. while playing bluetooth music its making high noise.
I have the same problem with a Bluetooth module as well.
can you explain me what exactly happens than? Why is the humming noise shorted out but the audio signal still present? I want to understand it, im a noob :)
Thanks
The noise source acts like it has a very high output impedance, but the audio source has a lower output impedance.
The noise is basically a voltage induced due to stray em waves from neighboring electronic devices and stuff and it has no ENERGY behind it, only voltage. Voltage without current is just a big mouth, all talk no action so the moment you say, here, sustain your potential difference across this conductor by inducing a current and therefore power dissipation in it the noise voltage just taps out and is like nah but the low impedance input from your audio player goes ahead and says meh I'll give you a little more current my man no problem but then of course if you connect a microphone or piezo then it's the same as the noise because yeah you don't have much ENERGY coming out of those either.
I like your explanation.
The hum doesn't have a lot of current backing it, while the actual signal does, therefore, it is effected to a MUCH greater degree than the actual signal you want. The hum is basically floating voltage, and the resistor biases the input to 0v. You must use a source that has adequate current to strong arm through that biasing though. Some 'line level' sources have quite the high output impedance, and a mod like this will significantly lower the volume.
Liked the clip. I would have thought to use a T-Filter. Didn't think to use a low value resistor. Thanks.
I have hiss like that when I turn on the av reseaver. And when I give volume to 0 the speakers scream. But no audio intput is jacked in.
On every input it is hissing.
Please help
i have a peavey pa amp head how would i quieting it itss a little hum and alot of wind its 260 watts...great hope u can help me thx alot
At the start of your video you show a pre-made amp, i have purchased an almost identical one of these very recently and need to reduce the noise. It has the same 3pin input as yours showed with L R and Ground. What would be the best method of inserting a 1K resistor on the input in this instance ?
The resistors don't need to be on the board. You can place them at another location, such as the input jacks if you are using them. This might be an easier way to place them.
adam201192 did you solve your problem? I'm using a 50k potentiometer but I still get the noise. Not sure if it's too high value or not grounded properly.
Kevin Livingston sorry I've only just seen this. It didn't solve the problem at all. I'm using the same amp as described in this video but I think that the audio/mp3/bluetooth module unit I'm using is causing a load of feedback noise.
I get humming from BP7004 just for plugging the power in. I have nothing else connecting to it, just power for the built in subwoofer. I check all my connections they are good. I did this with everything connected with and without to to the speakers. Please help I want to if I can save them or sale it off for parts.
try add a fan inside your woofer. i realized the heat sinks were not as effective to cool the transistors. it worked for me.
+JohnAudioTech I used a pam8610 for my desktop diy speakers, powered using the PSU's 12v rails. I have added a resistor and cap, and while the amp is quiet and plays well using my cellphone as a source, when I plug it into my desktop's soundcard, where it is intended to be plugged in, it has horrible noise (very loud noises and popping), and same when I use my laptop's headphone jack as a source. Could you advise how to get rid of this noise? Thanks much!
That is probably because of the ground. Try adding a ground loop isolator (Audio Transformer) should work just fine :)
Try unplugging your laptop and running it on batteries. 9 times out of 10 noise generated on the headphone socket in laptops is due to extremely noisy switch mode power supplies.
It could be also the fault of the 12v Psu. They tend to generate a lot of noise and go unstable without any load.... So try hooking up a load to it. But it doesn't seem like that is the main problem over here. It is definitely the ground. Adding the Ground Loop Isolator is gonna solve this issue..... It isolates the ground of the amplifier and the ground of the audio source.
What is the IC number you are using, do you give me its Circuit Diagram please...
Automatic subscribe to this channels, a lot of experience here... Thanks
it's very effective now my amp is silent not buzz anymore
Help! I have in my RV a Jensen AWM970 stereo/DVD player. It has a loud humming/buzzing noise while playing the DVD on the tv. It also has a ghost line that travels upward & the more interior lights I turn on the louder the hum/buzz gets. Any helpful ideas to fix these issues?
Are you running off a power inverter? These devices can be quite electrically noisy. A quality filtered power strip may help but don't expect miracles.