STOP hum and buzz in your amplifier projects !

[@ahmeterden7337]

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.

[@sutharpiyush71]

Hey, Did you connect a single resistor? In between ground of input or input channel? 🤔

[@chinhchinh6265]

No it does not work. It just lower you hum and audio signal. But still buzz

[@captainjim1010]

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%

[@paulsagoe9582]

Please help me out. [phone] on WhatsApp

[@sutharpiyush71]

How exactly you add resistor with channel + ground? 🤔

[@KausikKumaar]

It works but audio quality/volume get reduced

[@captainjim1010]

@@KausikKumaar in my case audio quality got better

[@KausikKumaar]

@@captainjim1010 ok maybe i am using low resistance will try increasing to 10k

[@coffee_quaffer]

I’m learning PCB analog circuit design, and trying to master the LM386 before I move on to the big boys. This was exactly the issue I had with my first board, and bodging a 2.2k resistor from line in to ground fixed it. I also built the prototype while referencing your other LM386 videos. Can’t thank you enough!

[@stark_energy]

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.

[@pianokeyjoe]

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).

[@rodrigobarrera2666]

Hello, I was wondering if cable lengh matter and were to pick the shield if using 3.5 mm audio jack? Regards

[@chinhchinh6265]

What if it is just noise? I dont connected to any cable but it still noise, buzz

[@markb1911]

@@chinhchinh6265 An amplifier “looks” for a signal on its inputs, and amplifies them from a power source. But if the power that the amp is supplied with changes and is unstable, it can be amplified because even if there’s no input signal the amp sees a change in voltage level and differences in voltage level are also what an input signal is. Basically you can hear the amps power source or other things interfering with it because they are not supposed to be there and affect the amp like an input signal would.

[@thehudlessfarmer]

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 :)

[@chuckmaddison2924]

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.

[@ryantoomey611]

Another way is to use an isolation transformer on the audio or use a larger filter capacitor on the power supply.

[@diypasstime7785]

Where should the audio transformer be placed? In the audio input or output?

[@jiroyamada1139]

@@diypasstime7785 Input.

[@AJ-pf3pi]

Bro sounds like Tobey maguire😭

[@dizzie_vee]

Lol wtf bro?😅

[@MohamedWaheedAtef]

Spidey does audio circuits 😆🕸️

[@XaFFaX]

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...

[@lunarchsbrain2125]

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

[@codebeat4192]

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.

[@redakaysoumi3277]

yes you're right it's just a pull-down resistor and it'll work for most cases to avoid a floating state

[@researchandbuild1751]

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.

[@rich1051414]

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.

[@LeoGerritsen]

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.

[@oldschooljohnny]

Great video... we need more like this to help the average techie! Good work

[@shutdahellup69420]

1:18 How Dubstep beat drop be like...

[@TheOneWhoMightBe]

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.

[@sutharpiyush71]

Did it worked for you bro?

[@JohnAudioTech]

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.

[@Drdozzer]

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!

[@edrickmendez7978]

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?

[@josephkingston9252]

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.

[@carlosmaestre]

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?

[@Schjoenz]

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

[@endall39]

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!

[@saikrishnamethuku7892]

Resistor across input ? Power input or audio input ?

[@nithinpb7042]

@davinder singh how to connect? Can u share a connection diagram?

[@nithinpb7042]

@davinder singh I should attach a resistor on both L and R channel?

[@coffee_quaffer]

Audio input

[@kratomleaf8937]

wow that shrieking sound is awesome tho, i might want that to be a pedal effect for my guitar

[@dozyproductionss]

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.

[@jVonHausen]

Did adding the resister also shunt the feedback when touching the capacitor?

[@1marcelfilms]

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.

[@trei2unu]

love your videos sir! amplifiers are one of my hobbies so all of this is very interesting and teaching

[@AdikMusicOfficialTM]

How Dubstep was Discovered XD 1:18

[@Rainbow__cookie]

Lol

[@nickthevoice]

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 ! :)

[@S-Theo]

3:55 John Deley ? What song is this ?

[@DanubioRodriguez]

what cap can add to remove noise from an atx fan? in my tda7377?

[@DanubioRodriguez]

in high freq listen noise

[@1970Landei]

So just that I'm not wrong. A resistor between the input (+) and GND for each channel?

[@Jandejongjong]

Same question i had;)

[@FacundoAguilera]

@@Jandejongjong yes

[@joseveliz6979]

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.

[@FacundoAguilera]

@@joseveliz6979 No, yellow is the other channel.

[@BlackyZE]

@@FacundoAguilera in that case we would hear noise from other chanell that's not resistor crossed ...

[@dom3827]

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

[@RijuChatterjee]

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.

[@ItsDextrin]

I like your explanation.

[@rich1051414]

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.

[@jacksace8405]

which input wire you connect the resistor?left and gnd?right and gnd? or right and left?

[@MathewPanicker1010]

Look at 4:39

[@danielm.4359]

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?

[@pianokeyjoe]

You put the 1k resistor across what 2 pins of the input though? There are 3 wires on my input side, LEFT, RIGHT and GROUND. Are you putting the resistor across the LEFT and RIGHT pins? Or across LEFT and GROUND or RIGHT and GROUND?

[@JohnAudioTech]

Your last sentence is correct.

[@hendritresnahadi4146]

How about the volume, it would be decrese or go down right? Tx u sir 🙏

[@rhenry74]

Dang, wish I had seen this 2 months ago. It would have saved me hair pulling on my DIY build.

[@GarryGri]

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.

[@GotaSir911]

Solutions- Use DC-DC isolator Avoid ground loop Dont make your audio Jack an antenna Use 2 power supplys if you use bluetooth

[@AniketBasak]

AMOGUS

[@RexxSchneider]

Main solutions for hum: shield the input wires and keep impedances as low as possible.

[@roosar2001]

Twisted pair wont shield unless you're using a proper differential input. Just FYI.

[@ChudGippity]

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

[@praveenramachandran9445]

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? :/

[@bobhurley4369]

Hi, could you explain exactly what the resistor is actually doing, that causes such an improvement in the sound ?

[@JohnAudioTech]

It lowers the impedance of the input so when the source signal is off or disconnected, the amplifier is less likely to pick up hum or buzz on its input. It doesn't really have an affect to the sound in normal use.

[@RexxSchneider]

@@JohnAudioTech To be a little more precise: the audio source shown was designed to drive headphones, perhaps a 32 ohm load. You have a source with a relatively low output impedance, so lowering the input impedance of the next stage down to 1K doesn't reduce the audio signal, but it does significantly reduce the voltage generated by the magnetically induced hum _current_ by a simple application of Ohms law. Most headphone amps would be happy driving 100 ohms, so you could use an even lower value resistor if you still have some hum to get rid of.

[@muploads5877]

I'm very new to this kind of thing - at 2:21, is a 2.2k resister considered "higher valued" than 10k?

[@JohnAudioTech]

No, 2.2K, sometimes written as 2K2 is 2200 ohms and 10K is 10000 ohms.

[@rudyserlet8959]

Where can i find that little sony player ??? Whats the name or number of it ?? Thank you

[@KolfMAKER]

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?

[@JohnAudioTech]

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.

[@KolfMAKER]

@@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?

[@JohnAudioTech]

@@KolfMAKER Sounds like an open ground or shield ground. Check continuity with a multimeter if you have one.

[@yvonnemcclain652]

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?

[@JohnAudioTech]

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.

[@R2_Audio_]

Hi! Where should i put my resistor? Left and right audio input? If yes, then it didn't work for me, the buzz is still present.

[@Sokercandy]

Change the value.signal input+ ground.or use a buffer amp

[@amitghosh6966]

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 ?

[@JohnAudioTech]

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.

[@tallnrough68]

Across the L & R input ? Not the ground at all ?

[@abhishekmusic90]

Hello..im sitar player ..i also play electric sitar....i have a same problem.....can send me a circuit diagram to stop humming and which component use in the circuit please help me

[@LousyPainter]

Should the resistor across the input be equal to the input impedance of the amplifier?

[@RexxSchneider]

No. The problem occurs because the input impedance of the amplifier is a lot higher than it it needs to be, which makes the induced hum current produce a higher hum voltage at the amp input. You need to lower the input impedance of the amplifier as much as is practical to reduce the hum voltage by adding a resistor across that input. The lowest value of resistor will be determined by the lowest impedance that the audio source can drive - for headphone outputs, that's often around 32 ohms.

[@clee2423]

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

[@Tinker_Box]

Seraph I have the same problem all the time with a bunch of different amplifiers and I haven’t found an answer for that.

[@99hari55]

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 ...

[@fraaggl]

ok cool but i have female jack connector on my amp, so i have absolutely no clue on where to put the Resistor... I've tried randomly but no effect.

[@waynepryce34]

If I don't have a board like that, can I solder in between the wires somewhere

[@Albanez39]

Hoping you are someone responds to this: Can I put a resistor on the output? I'm trying to use a small 5V amp for my car, because connecting my phone through AUX emits audio at the lowest possible volume. I NEED an amp to use the car speakers (unless I go and wire them directly to the amp) through a 3.5mm jack. Hence, I'm giving speaker-level input to the car stereo, which demands line-level input. I tried using a bluetooth amps as well, but it produced a lot more noise. So...can I use a resistor on the 3.5mm jack that outputs the audio to the car stereo???

[@RexxSchneider]

If your phone is giving insufficient output for the car's AUX input, then you need a small amount of preamplification. For that, you want a preamp, not a power amp. Something like an NE5532 preamp kit with a volume control would fit the bill. John designed just such a stereo preamp for the same sort of reasons as you and he has a project video documenting it at kzbin.info/www/bejne/ZoDWaYCujZtgmbM .

[@silenozcefas1562]

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

[@nickybbchannel9987]

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

[@seandelong8818]

I'm working on a project in my truck. I bought a 12v 100 watt amp and hooked everything up and it sounded great with my truck off. Once I started the truck the input voltage would raise when I gave it gas (due to the the engine giving a higher rpm generating more "power") and thus began an ear peircing hum and backround noise. How would I fix a problem like this?

[@JohnAudioTech]

Sounds like a ground loop issue. Google ground loop automotive audio. you should be able to find good info.

[@seandelong8818]

@@JohnAudioTech alright I'll take a look at that and let you know.

[@robertneill3057]

Also the truck's alternator needs checking to see if it has a suppression capacitor fitted to the output. A 3uF 250v polyester/polypropylene film capacitor should suffice.

[@xerejuneseve6333]

Please help me.The LM3886T IC in subwoofer only give little buzz sound.No sound is transmitted or changed when i touch input,but preamp work just fine.I replace IC,all caps,and check for cold joints,the power is good 2x26V.Mute pin 8 is steering by two transistors,they are good to.

[@kevinlivingston9563]

Blahblox Gyuanox Did you find the problem? Maybe check your physical wiring to your speakers.

[@xerejuneseve6333]

Yes,the IC was burn,heat sink not sit properly.Replace to LM1875,works great now.

[@crazyexperiments4815]

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?

[@prolensphotography3823]

what resistor value I'm going to use if guitar to amp? any suggestion value of ohms

[@evergreatest7644]

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

[@marto1671]

Hi! I have a TPA3118 60w mono class D amp, wirh a 12v 1,5a power source from a dtv tv deco, connected to a 12v chinese bluetooth/radio/usb module, i wann hook up a volume potenciometer (i have a 10k and a 100k). Sounds loud and cool, the thing is that i get a lot of noise, i maybe put a B1212S, just guesing, and i dont know wich of the volume potenciometer put either, recomendation for the noise and the potenciometer? (first speaker project, and sorry for my english) Best regards from Argentina!!

[@amosou7923]

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

[@AjayJangra473]

1:52 audio input or power input??

[@electronicguy4550]

Audio Input

[@zapz2101]

ok, im confused. you gotte bridge the positive and negative leads? wont that short the signal?

[@rubikfan1]

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

[@Eliastaye6]

HELLO i have a question did you put the resistor in between the GND? or did you connect it to the left and right source

[@PDinNM]

between the input and ground on each channel. i.e. two resistors

[@Eliastaye6]

Thank you sir it worked. Am still in disbelief wow...thank you again lets keep the community growing!

[@megalodonscortex7578]

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.

[@thevinkerry]

try add a fan inside your woofer. i realized the heat sinks were not as effective to cool the transistors. it worked for me.

[@lee26carl]

John, good day. Mine has problem like someone is coking. Its on and off though.

[@daineball]

Small question I have a mini headset amp, it's portable and has its own battery when I charge it, it hisses like it's picking up signal, it charges with mini USB could the data connection be causing that hiss?

[@JohnAudioTech]

I would guess that it is noise from the power supply that is used for charging. They are often the switching type and can produce a lot of noise.

[@mohangabhale5555]

Can i use for 5v amplifier board like pam8403

[@MusicwithMohit]

+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!

[@adithyapillai4259]

That is probably because of the ground. Try adding a ground loop isolator (Audio Transformer) should work just fine :)

[@joshdau]

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.

[@adithyapillai4259]

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.

[@randomtube8226]

That sound when he touched the capacitor 😂

[@C40V15]

that's a cover. someone?

[@BeeOwGeeDeeAyN]

So there should be 2 resistors, one for each channel. Am i right?

[@IscleGaming]

yes!

[@Jandejongjong]

Aaaah

[@cinhuu]

Can you help me? Where do I connect the resistors in this image for example? techdelivers.com/image/cache/data/Sensor%20Modules/FM%20RDA/PAM8403-circuit-500x500.jpg

[@Anglynn74]

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.

[@Anglynn74]

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.

[@JohnAudioTech]

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.

[@RijuChatterjee]

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).

[@adam201192]

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 ?

[@JohnAudioTech]

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.

[@kevinlivingston9563]

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.

[@adam201192]

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.

[@kirankesav7608]

Hey john, can we use this at each stages, like before preamp, before poweramp etc.

[@ichigokurosaki105]

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?.

[@RexxSchneider]

You must use shielded wire for the input signal and ground the shield at one end of the wire.

[@YX4zf3]

Why does putting a resistor across the inputs work?

[@manusudha4269]

I was looking for something like this ...I will try your trick . Thanks !

[@Rhythm.Studio]

Value of resistor ? And can use a capacitor ? If yes, how much value for guitar to cut noise for grounding loop and RF to install at output jack

[@easygeorge3161]

I get a lot of humming while using my phone through the mixer ,, what device ,, which way is the best way around .. which isolator is the best one to use .. (inexpensive

[@tuonofly]

Hi, good video.. how can I do that with a tube amp Peavey 6505+....there are so many Hum when I the Loop's amp with a Pedal or a multi-effects from Boss. Then there is a ground loop. Thanks so much

[@piotrpolujanow7499]

use noise gates, one as first block, second one after amp. use good cables. I had the same problem with my 6505 and GT100

[@tuonofly]

Hi, thanks for your answer. Maybe my problem is a Hum from group loop... I use best cables und 4CM with the Gt8 in my 6505+. The noise gate is already activated in the Gt8 and if I use a second noise gate in the front the preamp, the Hum stay yet there. with 1 or 2 gates, whatever, don't work... When I use just one gate in the Loop, the Hiss from distortion is go out, but the Hum is there. When I use just a jack in the amp's loop (return) the Hum is there. So gate with that don´t work. That is my problem... Thnaks

[@inaamurraheem5036]

Sir if our amplifier is stereo than we must use two resistance???? Or one? And resistance is connected between input and ground??

[@jon123423]

Yes, two resistors are required for stereo. For mobile phones, iPod a 680r is fine, For pre-amp, you should experiment at 2k and above until best results are achieved. Better earthing can remove it too. Larger smoothing caps on the PSU will help as well - keep experimenting until you get the best results.

[@bappa4mbku]

Will this work on PAM8403 amplifier. If yes then what is the resistor value will be?

[@vrkiran9382]

is this work with usb bluetooth module receiver also? lm given 5v power through 7805. while playing bluetooth music its making high noise.

[@ryantoomey611]

I have the same problem with a Bluetooth module as well.

[@jimparsons6803]

Liked the clip. I would have thought to use a T-Filter. Didn't think to use a low value resistor. Thanks.

[@stevenjones5226]

How much power can this filter? Say I have a 3,000 home amp on some custom 20 speaker 10" towers

[@sciexp]

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

[@JohnAudioTech]

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.

[@sciexp]

@@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...

[@amosou7923]

Hello, Boss I saw impedance plug on amazon, will it useful to reduce hum noise? What hms should I choose? Thanks a lot.

[@ognjencolic7208]

WOW i have build a few amps in past month (just for fun) and i thought that only way to get rid of that input noise is to go ham on shielding input cable. Its really simple solution and it does work. I have one question and i think that you could help me with (if you have time to reply of course). I have Samsung TV with great panel but it surprisingly lacks any sound output but i can disassemble it ant tap some female RCA connectors on speaker but since i need line out not amp out will a few resistors in series do the job or i would have to do some voltage divider to bring the voltage to line level input,on my amp it says Sensitivity : 150mV and Impedance: 50kiloOhms . Thanks in advance

[@ognjencolic7208]

Thanks for the reply appreciate it. That is the problem its a single board design and size of the board is 10x10cm and its multi layer boars,its one of those pesky SOC,single chip with heat sink on it and some memory and some transistors. I found some AMP out to line level converters online so i will try to copy that design from net. All in all thanks and if you have some more elegant solutions please speak your mind :D Cheers

[@abuhanif4607]

Bro does DC OR AC electricity source fact in sound amplifier? And if I use 12V DC will it run 100 watt subwoofer. And does AC 12v fect on tip 122 and 127 IC?

[@Kalanchoe1]

First, all audio amplifiers operate on DC. AC input gets converted to DC by the powersupply. Second, can what run a 100w subwoofer? And also 100w @12v is like 8A. So no, 12v won't work because there is no way your speak has a DC resistance of 0.7 ohms. Normally, high power speakers use a high voltage so that they use less current for the power demand. Lastly, transistors do not operate on AC power, they are strictly DC devices.

[@junjungebutan843]

Wer the resistor put?is it the left right or ground??

[@Mt-xw2lh]

One in left + ground and one in right + ground. I think so

[@99hari55]

When i cut volume ....still Humming like ac 50hz ....why....?its present when i raise volume or cut volume ....!when i power up Amplifier those Humming present with signal or not signal.....but its not incresing with volume .....!why...?

[@RijuChatterjee]

If the amount of noise is unaffected by a gain adjustment on the amplifier then this can only mean that the noise is entering your signal somewhere other than the input.

[@ped-away-g1396]

sounds like a ground loop

[@92nredrappini84]

How can I eliminate noise/static in my house when I turn on the Treadmill, anywhere in house?

[@4malulz104]

Couldn't you build a ground loop isolation circuit? Basically you transfer the audio signal into another circuit by magnetic transfer which would eliminate noise on the current line, through a couple of coils, or a transformer...? I know this would eliminate any "leaking" dc currents... Then smooth it out with a few caps?

[@siggi51991]

The last images in the end was like the berry on the top of icecream :D

[@benliebenberg610]

Hi John, I have a problem and after watching your video, I thought I found the solutuon. I am build a bluetooth speaker and have 2 amps. I have a bluetooth decoder that feeds into the first amp (which has a volume control) and then the first amp feed into the second amp. The second amp goes into the speakers via the crossovers. The reason for the first amp is because the signal provided by the bluetooth decoder is extremely small so I am trying to amplify this a bit in order to get more volume from the second amp. I am a noob at this (as you can probably tell). I am powering all these from a single 12v source. The problem is that I have massive feedback when I pause my music. I have tried the resistor, on both input to the first and second amp but no difference. Any advice?

[@JohnAudioTech]

Is the first amp made for driving speakers or is it actually a preamp?

[@benliebenberg610]

@@JohnAudioTech its made for driving speakers.

[@JohnAudioTech]

@@benliebenberg610 If it's class D, it can be putting a lot of switching noise into the 2nd amplifier. I would recommend using a pre amp.

[@katherineward9086]

How would you apply that to a hand radio

[@scorpion18loco]

Thanks , it help me a lot, I was tired of shitty noise :)

[@summersong88]

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?