Noise or Music?

The "Bose" sound system is based on chamber resonance like that of musical instruments. This is the difference between a whistle and a flute. The mouth piece of a trumpet is raw without its additional plumbing. The noise of a piezo-electric sounder is raw, but chambered to resonate...better. A trumpet is basically an acoustical waveguide device. Consider this and lets see if you can "WOW!" the crowds with your sounds. The trumpet mellows the sound of the mouth piece by reflecting the sound repetitively off the inside walls of the horn. The angle is low so the acoustic wave reflects many times along the length. What works for you?

Question by robertgrist   |  last reply

Fix noise in amplifier?

 recently make a lm386 amplifier  test it with battery and my eleminator power supply it is working fine. i also add a filtering capacitor. But when I connect it to a 12v adapter it marking some hum noise .So how can I repair it?

Question by Soumojit   |  last reply

Cheap Chinese Audio Amp: How can I reduce the noise? Answered

I have a $2.50 audio amp from China.  It's what you'd expect: some rusted components, some scratches on the PCB, and yet it still works.  I use it with a 9v battery, my phone, and a big, repurposed car speaker.  It get's loud enough I think it can easily destroy the speaker with that 9v.   My question: At any volume worth using that amplifier for, there's noticeable noise.  What can I do to remove this?  Some research shows that a capacitor may help, but where would it go?  Thanks

Question by bobdabiulder   |  last reply

Make some noise with 110v sensor

I have a presence sensor 110v (lights a lamp) and I need make some noise too. I already insert one ac adaptor 12v with a resistor anda a pc speaker and make a irritant noise, anyone have othe idea thanks

Question by mouserock   |  last reply

LEDs are putting static on my stereo?

I wired a outlet so I could plug in a strip of LED lights that are able to run in different modes (flash, fade, different colors, etc) When I turn the LED lights on, the stereo, that is plugged into a different circut, has static that goes with the tempo of the lights. When I turn the lights off there is no static. What gives? Here is what I got. I used them in another part of the basement and they work good with no problem. i also checked the outlets with the 3 light tester and it says it is wired correctly.

Question by rodsteryz   |  last reply

Help with some noise filtering? Answered

I've attached a file of a project I will build, but should I need some noise filtering capacitors? Thanks, BoK

Question by Balls of Kevlar   |  last reply

I want the background noise!

I have a recording of a conference call I have to transcribe. Unfortunately the recorder was placed near a noisy co-worker, who has become the main sound during the recording. Is there some way to pull out and enhance what is now the background noise, my important call?

Question by    |  last reply

Noise filter on iPod dock

I recently completed a project where i made my own iPod Touch charging dock for a set of PC speakers. While testing it out i noticed there is some background noise/feedback coming through the speakers any time the iTouch is actually charging. Is there any way i can shield against this interference? Or is the proximity of the headphone jack to the iPod connecter to much of a problem to overcome without alterations to the iTouch itself? I've notice this problem before while listening to my iTouch through it's speaker or headphones when it was plugged into a wall charger or PC.

Topic by mpilchfamily 

Active Noise Reduction as Software--possible?

While on vacation last week, I was trying to watch a sophisticated, complex movie (something with Muppets) on a laptop and was having trouble hearing the audio through headphones, due to the general loudness of my family.Is it possible to actively reduce noise through computer software? I assume that the programming itself would not be too complex, but I don't know if the time taken to process microphone input and use it to modify audio output would be too slow. The only place I found through Google that discussed this was a forum wherein the members couldn't get past the concept of attaching a microphone to a headset. I also found a schematic with instructions for building headsets, but I would prefer a .exe file.

Topic by CameronSS   |  last reply

removing power supply noise from my bluetooth speaker

Hello guys, so i made this bluetooth speaker and when i hook everything up and runing i get this weird noise from it im pretty sure it has something to do with the voltage step up but im not sure how to remove the noise would be great if you could help :)  yeah yeah i know the schematic is pretty epic, lets pretend that the two amp audio input and bluetooth dongle audio output are connected, and ignore the fact that there are no switches and stuff like that pretty sure thats not hwat causing the noise.   i know that theres a way to remove noise by using capacitors but i dont really know how to use them. thanks for tips :)

Topic by VytasŽ   |  last reply

my sisters old stereo system seems to be making a 'ttit' noise when i listen to a song with bass. Please help!

it sounds sorta like a small piece of meatal rataling (or a spark jumping through the air) . the speakers are nice sony speakers but are old and have been out in an OLD barn. the speakers connect bye a wire in a clamp. there are two different rows that have a red and black wire ports, but only one row works. please help?!?!

Question by jayman242   |  last reply

60 cycle hum in a power supply

I recently scavenged a 5 VDC phone charger to use as a power supply for my small FM transmitter. I have the transmitter plugged into the computer so I can listen to my favorite internet radio station on the stereo in the living room, rather than only in the office. The whole thing works really well, except that during quiet songs or in between songs, I can hear that 60 cycle hum coming from the radio. Does anybody have any suggestions (cheap, free, or re-purposed parts are a plus) on how to minimize this? I don't want to spend money on this, and simple is my favorite adjective with electronics projects. Can I put a capacitor across the + and - wires to smooth out the power? If so, what size would be good? Thanks for your help! ~PC

Topic by Poppa Chubby   |  last reply

How do I make a noise-detecting traffic light?

I am not sure how many people have seen these, but they are used in Elementary school alot. Basically, when the light is green the noise level is at the right level, if it is yellow it is getting a bit too loud and red is WAY too loud. I want to use this type of idea in my classroom. It doesn't have to be a traffic light but a series of light. I just don't know much about wiring.

Question by MrFish7   |  last reply

Slowing a noisy handheld fan?

I am trying to slow a battery-powered (two AA batteries) handheld fan. It's obnoxiously loud for my project, but slowing it to about half speed will help cut the noise. I think running a resistor somewhere in the circuit will do it (planning to lengthen the wires anyway, so physically adding in isn't the issue,) but frankly there's a reason I'm in art instead of engineering. I've looked at the online calculators, but they want the amperage of the motor, which I don't know. What kind of resistor do I need?  Or is there another way to slow or quiet it down?

Question by jblanc   |  last reply

How can I fit a Semi Truck horn onto a bike or a Vespa? Answered

Infmom on Lifehacker had an idea here - - and personally I think it might safe a few lives. I'd love to hear anyones' thoughts on this.

Question by Aquilla   |  last reply

I have built the "Sweet Portable Guitar Amp" but there is a very load hiss.? Answered

I have built this and its working fine, except there is a very load hiss along with the audio. I have only made 1 modification: I have connected the negative terminal of the battery to the 2nd signal of my stereo 1/4 inch socket, and the ground to the ground circuit ground. This causes the circuit to turn on when a mono jack is plugged in. Any ideas why I am getting this hiss? It sounds a bit like static on a TV but I have used shielded cable. Thanks

Question by geniass   |  last reply

Ground loop question? Answered

Hello , im making a little guitar amp with ROG tonemender as preamp and tda2003 power amp.This is my schematic , can you check it for me please!. Will it get ground loop problem ?? My English is bad so i can't understand clearly some documents about ground loop. i have 2 seperate board (a power amp based tda2003 and a ROG tonemender as preamp).They will use the same power supply .some thing like this picture and this is schematic Thanks!

Question by login721   |  last reply

Sounds with electronics

So here goes, I am trying to figure out how to make basic sound generating machines. Preferably generating a sound that can be modified with a potentiometer or something of the sort. The principle is simple, these will be for messing around, possibly, if the result is good, using in some random recordings of mine, so most of the machines will have a jack out plug. Anyhow I was wondering, what, in a circuit, actually makes sound, what is the base of all sound generating electronic devices (synth, analog stuff, beepers) what actually creates the wave, the current that is sent to the speakers? Have I just answered my own question by saying current? Is it just the electrical current, and putting random resistors, capacitators, potentiometers and stuff changes the sound that is generated? Any help is more than welcome! and if anything good comes of it, I'll post some sound clips!

Topic by gavox   |  last reply

Cell Phone Noise in FM Transmitter

I have recently built a dock for my HTC touch for use in my car. The dock is basically a holder with a cheap FM transmitter in the back. The FM Transmitter and cell phone are connected in parallel to a 5 volt USB car charger. For some reason, the FM transmitter is picking up noise from the cell phone. It is digital noise, different frequencies and beeps that vary depending on what I am doing on the phone. The noise is very quiet, but still there. Is there any simple solution to filtering out this noise? Will a simple capacitor do? Thanks Andrew

Topic by computerwiz_222   |  last reply

electromagnet gauge makes buzzing noises?

Hi, i've been working on a project that involves reusing the electromagnetic needles commonly used in 90's era ford gauges. i can get it to work fine, but it seems to cause a buzzing noise as it is doing the work. there are three pins, ground, power, and signal. right now i just have it working off of 5v. when i have it going, and you hold the needle with your finger, you can feel it vibrating. i'm using an arduino nano, a npn transistor, and the gauge with a PWM output. do i just need to put a capacitor in? or how do i keep it from buzzing like it does? its not a loud buzz, but you'd notice it if you were in a quiet room.

Question by zack247   |  last reply

How to eliminate noise in FM transmitter? Answered

I had made a FM transmitter using IC NE555. When i power the circuit with 9V battery,the transmitted audio is clearly received in my radio receiver.The problem is the battery will soon drain out and also as the battery starts to drain the transmitted frequency changes without my knowledge.So as the battery voltage decreases the frequency is also changing.To eliminate this problem i used transformer powered source with 9V Regulator 7809.When i power the circuit with transformer the received audio signal on my radio receiver has so much of noise added.The audio quality which i transmitted is completely lost.Anyone Help me to resolve this problem.

Question by Rajkumar2506   |  last reply

Digital noise in battery powered system Answered

Hello, while building a Bluetooth speaker based on this instructable, I ran into some problems regarding noise. There already exists a question regarding this problem here, but it is a few years old, and it gave me no solution. The power source for this project is a self constructed battery pack consisting of 4 18650 battery's soldered to a battery protection circuit (just like in the instructable). The PAM8610 (black version) amplifier board, however, can't take 16.8 volts so a voltage regulator is placed in between set to 12 volts. Same story for the Bluetooth receiver board (KRC-86B V4.0), but with a voltage of 5 volts. All fine and dandy till there. The KRC-86B has an input for a 3.5mm jack connection and an output. The output is a pass-trough of the 3.5mm input unless a Bluetooth connection is present, then the Bluetooth signal will overwrite. Here's the problem: whilst the connection using the 3.5mm jack works fine, creating a Bluetooth connection results in a very annoying digital noise. This noise is there instantaneously and is the same on all volumes of the host/transmitter. If no music is being played by the host for around 15-20 seconds the device seems to enter a power saving mode and the noise changes to a regular beep. This is way less bad, but of no use because it is replaced again by the bad noise when the music starts again. I have tried a diversity of things, listed here with their effects: Action: wrap the Bluetooth receiver in electrical tape and aluminium foil. Result: nothing much, it didn't even block the music. Signal was only blocked by three layers, a few meters distance and my body in between my phone and the receiver. Action: lift ground in signal between Bluetooth receiver and amplifier. Result: noise gets slightly worse, no change in tone, only amplitude. Action: moved away from my computer, as to avoid interference. Result: nothing at all. Action: tried another Bluetooth transmitter, PC instead of phone. Result: - Action: broke the previous board at the start of this project by heating it too much in the attempt to change a wire. Result: noise was also present at the first board which I did test by hooking it up to the line-in of my computer. Though that could also have been by the ghetto set up I used. The 3.5mm cable was poorly connected, trough a breadboard. Taking my multimeter and measuring the difference between negative of the battery and GND of the voltage regulator for the amp gave a 6.0 mV reading. The same result is achieved when measuring between battery and GND of the regulator for the KRC-86B. The potential between GND of the signal and the GND of one of the regulators was 0.1 mV. I understand that you might want to hear the noise, so I recorded it: link. It is very soft, but audacity doesn't read .m4a files, and turning up the volume works just as well. Please let me know if you have any idea's on what could solve it and/or if you need more info. Thanks in advance.

Question by arduinefier   |  last reply

Can any (Physicist) explain this laser-weirdness that I'm seeing? Answered

I've got some cheap-o red-lasers. Up close on surfaces I see what looks like old-fashioned monochrome TV static in miniature* (and red). Other people see it too, I think it's some kind of "Quantum-noise" but would like other opinions. L *I don't like looking at it - it reminds me of this.

Question by lemonie   |  last reply

Does anyone know how to make a dynamic normalizer? Answered

I need to make one for my parent's TV so that the commercials don't deafen them! A dynamic normalizer smooths the volume levels between commercials, songs, etc. so you don't have to change the volume.

Question by Argon27   |  last reply

Need help with change value of capacitor in tone control?

Hello .im making a TubeScreamer TS808 clone. In the original schematic they use 2 0.22uF Tantalum capacitors, but i don't have them, so i replace with 0.22uF Mylar capacitors.The result is when i turn the tone pot up, i get noise and loud hiss. Can i replace the 0.22uF Tantalum with 1uF Tantalum then change the value of some resistors to make the tone pot to work ?This is the original schematic and my modified version .I not tested it yet because i have to order parts to build it.Can you check it for me please! Im beginner and i dont know what part i have to replace if i replace 0.22uF capacitors with 1uF capacitors. Thanks! and sorry for my bad English!

Question by login721 

how to kill the loud annoying boom boom from cars?

i am wondering is there a way of over riding speakers to play my own music or just stop the boom boom coming out the car in front at traffic lights? i remember a broad band am frequency was mentioned once at one place of work but need your knowledge.?

Question by patternbill   |  last reply

Sound effect button?

I'd like some instructions on how to make a button that plays the same 2-3 second audio sound when it is pressed. It should be able to last for a pretty long while if you know how to do that. I want it to look like it's DIY and not from a factory but also good enough that someone would put it on their desk.  I need the cheapest possible way to do this as well as instructions for a dummy who doesn't know much about technology. Thanks to anyone who can help!!

Question by Tofus   |  last reply

I'm selling build your own mini synth kits

Hi, I'm selling kits of an Instructable I made to build your own synth. The EM-Tronic: This kit provides you with the components and instructions that you need to build a small handheld digital synth. All you need to do is build the kit and find an enclosure to fit it into. I'm selling them on Etsy: Here is the Instructable if you want to build your own: Cheers, Brian

Topic by rarebeasts 

Piezo buzzer won't work? Answered

I have a couple of Piezo buzzers that I bought from the Adafruit shop, but when I connect them to a power source, they don't buzz or make any noise... Am I doing something wrong? Or am I not doing something?  Heres the link to the buzzers I have:

Question by Zem   |  last reply

need help with using one power supply to power multi guitar pedal? Answered

Hello . i have two DIY guitar pedal , they work normal in a chain and each of them use they own power supply( 9v AC-DC adapter).Now i want to use one power supply to power both of them.So , i wire them like the picture bellow, and i get the 60hz noise. Can you please tell me how to get rid of that noise. Thanks in advance ! sorry for my bad English.

Question by login721   |  last reply

how to avoid ground loop when use one powersupply for multi guitar pedal? Answered

Hello . I going to buid a guitar pedal witch have 2 boards in a box and use a power supply to power both of them.But i dont know how to wire them to avoid groound loop problem.Normal i will do like the picture below .Do i need to cut any wire to avoid the noise ?? Thanks for advance! sorry for may bad English!

Question by login721   |  last reply

Piezo Freebies?

I know there are lots of websites were you can get free electronic parts and sample. I am looking for some piezos and I was hoping I could find them on these sites, but I'm having trouble. Any suggestions? Any sites that have them?Any help appreciated.?

Question by mkupps   |  last reply

Portable Guitar Amp Hiss

Hi all, I have built this design with a few modifications to accommodate for the parts that I already have. I used a stereo 1/4 inch stereo jack, but I connected the 2nd signal to the battery negative and the ground to the circuit ground. This way the circuit switches on when I plug in a guitar. I also used headphones only instead of a speaker, so I don't need a switch. Now the circuit works and it is amplifying the sound, except there is a very load hiss. I am assuming that a certain frequency in not being filtered out but this may not matter when using a medium quality speaker because of its low frequency range. However high quality earphones can play this sound. Is this correct? Does the headphone work for anyone with the hiss? Thanks in advance

Topic by geniass 

How to reduce signal noise in a circuit (for Amplifier)?

I am building a sound reactive RGB light. Using a LM386 and a 16f88's AdC. I got it to work great with just 1 RGB LED on a breadboard, powered from a 7805 I then built it on perfboard, watched the amp's output on my O-Scope, worked fine. this schematic for LM386Once I hooked up 3 Constant current regulators with 3x 3 watt LEDs(red-green-blue) through 3x MOSFETS, the Amp's output signal becomes blurry/chaotic and the light malfunctions. The regulators negative output must be connected to logic GND, which i know to be where the interference is coming from.How can I reduce the noise coming out of the Amp? Even if I gotta use different type of Amp. I don't know to much about them.

Question by PuffMag1cDrag0n   |  last reply

Fix Noise in usb mp3 player kit

I recently buy a usb mp3 player kit I search internet about its connection and I connect all thing correct to my amplifier .  My  amplifier s good but there is lot of noise in the song I cant hear it properly So what  I do?

Question by Soumojit   |  last reply

Noise in Amp from LED Strip & servo

Hi, I am working on a project in which TL072 is amplifying an audio signal which is going to speakers & arduino analog input. Amp is powered by a wall wart with 12V 2A output. The same 12V is also regulated to 5V and used to power an AVR. The AVR is being used to PWM, using a power transistor(TIP120), an LED strip taking 1A from the same 12V supply. There  1) Now the rapid switching of current for LED strip is messing up the amplifier output. It's working fine with LED Strip off but when using PWM, there is a high frequency noise in the amplifier output. I have a 0.1uF and 10uF caps near power inputs for both AVR and amplifier. This is probably due to insufficient decoupling. Can someone please help me make it better? 2) There is another independent source of noise I'm finding which I'm unable to explain. The audio is going into Arduino which is controlling a servo as well. As soon as the servo is connected, there is a constant loud noise in amplifier output. This remains even after powering the arduino and servo using seperate USB supply(only ground connected). I placed audio setup and servo data wire far apart since they may be interfering due to PWM used for servo, but it wasn't of any use. Since in both cases, amplifier is producing noise, I think my amplifier diagram might be at fault. If I remove the amplifier, the audio stream reaches arduino without any noise . Anybody got any ideas how to remove these 2 noises? Attached images: amplifier schematic, graph of audio input in Arduino analog pin. -Antzy

Topic by Antzy Carmasaic   |  last reply

Could you convert noise pollution into energy? Answered

Since Microphones turn sound energy into electrical energy, you think you could generate any usable amount of electricity from an array of dynamic or piezo microphones near a noisy intersection or metropolitan area?

Question by action_owl   |  last reply

why wont my computer make noise? Answered

My computer(windows 7 laptop) is 3 or 4 years old and recently YouTube did not work we fixed that but now there is zero sound coming out of it speakers headphones you name it and windows media player says something like this:  Windows Media Player cannot play the file because there is a problem with your sound device. There might not be a sound device installed on your computer, it might be in use by another program, or it might not be functioning properly. Any help appreciated!

Question by FarmerKJS   |  last reply

Arduino/ESP8266/servo noise when idle

Hello everyone My project involves a robot with LEDs, servos and an Arduino with a Sparkfun ESP8266 shield on top. Everything else works fine, I send web requests to the robot and LEDs are blinking or the servos are moving. The problem is that when idle I have noise on the servo. I have tried  1. Pull-up and pull-down resistors 2. Providing external power to the servos 3. Putting an aluminium foil between Arduino and the shield and the problem persists Commenting out parts of my code I isolated that the noise appeared upon uncommenting this part of my code void serverDemo(){ ESP8266Client client = server.available(500); } but I cannot understand why.  Could you please propose me any idea? Below I have the entire code #include #include #include const char mySSID[] = "xxxx"; const char myPSK[] = "xxxx"; ESP8266Server server = ESP8266Server(80); Servo myservo1; Servo myservo2; int pos = 0;    // variable to store the servo position int pos2 = 180; int led1 = 12; int led2 = 13; const String html = "HTTP/1.1 200 OK\r\n" "Content-Type: text/html\r\n" "Connection: close\r\n\r\n" "\r\n" "\r\n" "\r\n"; void setup(){ Serial.begin(9600); initializeESP8266(); connectESP8266(); displayConnectInfo(); serverSetup(); myservo1.attach(11);  myservo2.attach(10);  pinMode(led1, OUTPUT);     pinMode(led2, OUTPUT); //testing myservo1.write(45);   delay(15); myservo1.write(80);       } void loop(){ serverDemo(); } void initializeESP8266(){ int test = esp8266.begin(); if (test != true) { Serial.println(F("Error talking to ESP8266.")); errorLoop(test); } Serial.println(F("ESP8266 Shield Present"));} void connectESP8266(){ int retVal = esp8266.getMode(); if (retVal != ESP8266_MODE_STA) { retVal = esp8266.setMode(ESP8266_MODE_STA); if (retVal < 0) { Serial.println(F("Error setting mode.")); errorLoop(retVal); } } Serial.println(F("Mode set to station")); retVal = esp8266.status(); if (retVal <= 0) { Serial.print(F("Connecting to ")); Serial.println(mySSID); retVal = esp8266.connect(mySSID, myPSK); if (retVal < 0) { Serial.println(F("Error connecting")); errorLoop(retVal); } }} void displayConnectInfo(){ char connectedSSID[24]; memset(connectedSSID, 0, 24); int retVal = esp8266.getAP(connectedSSID); if (retVal > 0) { Serial.print(F("Connected to: ")); Serial.println(connectedSSID); } IPAddress myIP = esp8266.localIP(); Serial.print(F("My IP: ")); Serial.println(myIP);} void serverSetup(){ server.begin(); Serial.print(F("Server started! Go to ")); Serial.println(esp8266.localIP()); Serial.println();} void errorLoop(int error){ Serial.print(F("Error: ")); Serial.println(error); Serial.println(F("Looping forever.")); for (;;) ;} void serverDemo(){ ESP8266Client client = server.available(500); if (client) { String req; while (client.connected()) { if (client.available()) { String c = client.readStringUntil('\r'); req += c; Serial.println(req); if (req.indexOf("hands") != -1){ hands_up(); } if (req.indexOf("leds") != -1){ leds_flash(); } } } client.print(html); delay(1); client.stop(); } } void leds_flash(){ digitalWrite(led1, HIGH); digitalWrite(led2, HIGH); delay(200); digitalWrite(led1, LOW); digitalWrite(led2, LOW); delay(200); } void hands_up(){ for (pos = 0; pos <= 30; pos += 1) { pos2 = 180 - pos; myservo1.write(pos2);             myservo2.write(pos);             delay(15);                      } for (pos = 30; pos >= 0; pos -= 1) { pos2 = 180 - pos; myservo1.write(pos2);             myservo2.write(pos);             delay(15);                      } } Thank you!

Topic by ManosZ1   |  last reply

Why is my 555 timer keyboard starting with noise? Answered

Hi!!! :/) I have made a 555 timer keyboard using a tactile button series with resistors, but rather than staying silent until I press a button, it makes noise as soon as I start it. All the buttons function properly, raising the note in intervals but it starts with sound. I have thoroughly searched my button/resistor series for accidental bridges between joints but have found none. This is my first "real" soldering/perfboard projects, so mistakes could have been made! Could there be any other reason for this noise? I cannot find somewhere else where the circuit may be completing. I have included the schematic I am using. Any help would be appreciated ]:>)  Thanks!!!!

Question by ToggleSwitch   |  last reply

Add simple tone control problem Answered

Hello , i have a problem when im making my portable amp.I use the little MK2 schematic , but i want to add a simple tone control , then i place the tone control between buffer output and power amp.But the problem is noise.When i turn down all knobs (treble,mid,bass) the noise decrease but still noticeable.When i turn up the Treble knoble the noise is very loud .I dont know why and how to fix it.Please help! Thanks very much ! sorry for my bad English.

Question by login721   |  last reply

How can I fix a broken noise canceling headphone cable? (It has four cables, not three)?

I accidentally broke by Sony MDR-NC7 headphone's cable, and when I tried to repair it I discovered that it had four cables instead of the usual three. Does it have anything to do with the fact that they're noise-canceling headphones? Two of the cables are golden, one blue and the last one red.

Question by The Landon   |  last reply

Washing machine makes a "clunk" noise throughout the washing process. What could it be?

During the washing process there is a clunk (once) noise. It occurs after filling but before agitation; after agitation but before emptying; after emptying but before filling for rinse etc. Wondering if this is a transmission or gear problem

Question by    |  last reply

Witch transistor should i choose for low noise audio ? Answered

Hello , im making a guitar pedal .The original schematic use transistor BC107B (epitaxial NPN) but i dont have i find some other NPN transistor to replace it. I have 2N3903 ,2SC1815,2N3904 , but witch should i choose for low noise application ? in their datasheet i found the "NF : noise figure" , the lower NF mean lower noise ?? BC107B         NF  Typ.= 2  Max.= 10 2N3903          NF  Typ.= -  Max.= 6 2N3904          NF  Typ.= -  Max.= 5 2SC1815       NF  Typ.= 1  Max.= 10 Thanks for advance! sorry for my bad English.

Question by login721   |  last reply

Capacitor replacement help needed: high pitch noise with new cap and dvd tray wont open?

I just wrote this question and i pressed cancel to cancel upload images and it deleted the entire question!!!! i will rewrite this breifly. i replaced cap in dvd player and new one makes high pitch noise and dvd tray can't open. new cap was from old electronics, is it bad too? written from ipod touch

Question by poiihy   |  last reply

Help! Magnetron in microwave oven makes jackhammer noise.

My microwave oven was out of order, it kept blowing up the power fuse; finally the trouble was traced to the power capacitor that was shorted. So, the power capacity was changed and the oven worked again, but now the magnetron becomes noisy with a jackhammer noise when it is working. This noise starts when the magnetron starts working, but it stops after some two minutes while it continues to work up to the time adjusted for it to finish its operation. What has happened to the magnetron? Is it possible to fix it? On the other hand, it is my best suspicion that it is the magnetron that is making the noise and not the transformer. What is your experience in this situation? This is exactly the sound (click on the link below) I am getting from my microwave oven, but it does not go and on until the machine turns off; the sound stops some two minutes into the operation, and the remaining time there is no longer the sound or noise – for the remaining time it keeps ‘quiet’ up to the completion of the time period it has been adjusted to operate, or I turn the switch knob to off. Thanks for any help or information.

Topic by Marius de Jess   |  last reply

My computer keeps making annoying beepy noises.

And has been doing so for the past 6 months. I have been able to deal with it for this long, but it has finally gotten to me. The computer is a HP Pavilion dv7 running Windows 7 Home Premium. It is not coming from the speakers, I think it is coming from the circuit board. I am sure it isn't coming from the speakers because 1) When the headphones are plugged in, the sound still comes, but not from the headphones (all sound reroutes to the headphones when they are plugged in) and 2) The sound still comes when the volume is turned all the way down. Please help, it is SO annoying. Thanks!

Question by kcls   |  last reply

How to eliminate PWM noise at slow speeds when using a PC fan? Answered

My power supply has a cooling fan inside. I wanted to slow it down to reduce the fan noise. When i use this circuit in the picture the PWM works great except for the low speed buzzing. Turns the fan into a speaker. Is there some way to eliminate the buzzing?

Question by WWC   |  last reply

Any ideas on an in-ear white noise device to help stutterers/stammerers?

Hi, This is my first post. I don't know much about this kind of tech but am eager to learn.  I want to build a hidden/discrete wireless earpiece which can play a short burst of white noise (1-2 seconds) when a button is pressed (see below for an explanation of why on earth I want to do this). The button would need to be able to trigger the white noise from a range of around 1 metre so that the controller can be kept in my trouser pocket. There are earpieces around which play white noise (to help people sleep in noisy environments) but I want to be able to control whether or not the white noise is playing. I thought about using a wireless earpiece (e.g.) with bluetooth, however it seems like the maximum range for this would be around 40cm. Anyone know of alternatives?  WHY WOULD I WANT TO?! Individuals who stutter/stammer often experience blocks. It's not that you'll hear them repeating sounds or anything - their speech just totally freezes up. For reasons which aren't entirely clear, listening to white noise can help stutters who block to start talking. White noise can be played before trying to speak, disrupting our auditory feedback - resulting in less blocks. Some devices have made use of this, e.g. Edinburgh Masker (, but were ugly, bulky and didn't allow you to manually control when the white noise was playing. Other devices, like SpeechEasy make use of Delayed Auditory Feedback ( - which can help some people but is of no use if you aren't already making some kind of noise. Is this impossible?  Many thanks for anyone with ideas on this! Cheers Oli

Topic by ocheadle   |  last reply