Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [hum]

29 questions
11
votes
7 answers

Fender Telecaster guitar makes loud humming noise, stops when player touches strings/metal parts

I have a Fender Telecaster that hums loudly--much more so than other similar guitars. It's a standard Tele with single-coil pickups. The humming noise stops when the player touches the strings or other metal parts of the guitar. The guitar is…
Willis Blackburn
  • 1,217
  • 1
  • 13
  • 24
6
votes
2 answers

Troubleshooting Hum in a Tube Guitar Amp

I have a Fender Deluxe Reverb Reissue guitar amplifier that hums whenever I turn on the reverb. It sounds like loud 60 cycle hum. The reverb effect is still applied, but is accompanied by the hum. Here's what I've observed about the hum: -It only…
Avid Pro Tool
  • 501
  • 3
  • 14
5
votes
2 answers

50/60Hz Noise Harmonics

I want to wirelessly communicate over low frequencies (<1kHz), and I noticed during some tests that 60Hz noise is showing up a bit at 180Hz (3rd harmonic), and also slightly at 300Hz (5th harmonic): (Ignore the stronger signal I was…
abc
  • 619
  • 6
  • 21
4
votes
1 answer

phono preamp hum - ground loop?

I've built a simple 2 stage active/passive phono preamp. Everything in terms of amplification/frequency response/lack of distortion works fine - just as it was designed. The only thing is that hum can be heard despite connecting GND to turntable…
cubix
  • 231
  • 2
  • 13
4
votes
1 answer

How do you know if a vacuum tube is going to suffer from AC hum or not?

I know that technically there is little difference between AC or DC heating of the tube - if it gives proper voltage everything is fine... Except the hum: I have read in various sources that some preamp tubes are very resistant to AC hum and can…
Giedrius
  • 365
  • 1
  • 8
  • 25
3
votes
2 answers

Can appliances or wiring hum at frequencies of 500Hz and above?

I've been hearing this strange continuous hum in my apartment for a while now. It is a small apartment and the hum is present all throughout with varying intensities, so I can't really infer from which direction or room it is coming from. I used an…
Discord Warrior
  • 31
  • 2
2
votes
1 answer

Active Tone Control Hum and Buzz in Potentiometer

Here is another problem with my circuits, that I cannot solve. I am working on analog active tone control - Bass, Volume and Treble with TL081/82 chips. The reason I put volume control on the output of first TL chip is to reduce hum in the tone…
mrkefca
  • 71
  • 9
2
votes
3 answers

Mains hum without ground loop

When I hook a device to the monitor input of my digital piano, I get a very noticable 50Hz hum. I understand that the monitor input doesn't have to be particuarly good quality, but it really is annoying. I'd know what to look for if the attached…
Stefan
  • 209
  • 1
  • 7
2
votes
3 answers

How to filter hum from transformer for audio rectifier

i´ve just build a prototype speaker from a TDA7293 (http://www.ebay.de/itm/TDA7293-85W-100W-Mono-Audio-AMP-Amplifier-Board-AC12-50V-Update-vision-TDA7294-/201478109342), the circuit is quite straightforward. To avoid the noise of a switching power…
Coliban
  • 226
  • 2
  • 7
1
vote
0 answers

Connected my audio input to two music systems by splitting the input, but the one with subwoofer produces continuous 100Hz hum

I have 10 year old Creative 2.1 audio system that has fairly capable subwoofer, and combined its input with a TPA3110 2x15W stereo amplifier module (for better treble). When both systems are powered together the subwoofer produces a humming sound of…
Zenvir
  • 11
  • 1
1
vote
1 answer

why does my USB 5V power supply not need a mains ground?

Every small 5VDC power supply (wall wart style) I see has the standard 2-prong Europlug, i.e. no ground. Even those with a British 3-prong plug just use a plastic prong for ground. Background - I am powering a small ARM board with such a power…
Per Jessen
  • 11
  • 1
1
vote
1 answer

Triac dimmer makes audible noise (hum or buzz)

I have some triac dimmer from IKEA (bought several years ago). This dimmer makes audible noise (hum or buzz), very notable during night when it is placed on a bedside table. I failed to find the culprit. I reverse engineered this circuit. This…
Chupacabras
  • 5,394
  • 2
  • 23
  • 50
1
vote
0 answers

Measurement setup for power line spectrum

I've come across a setup for measuring AC power line spectrum. Here is the spectrum graph which shows 60Hz and harmonics in a power line voltage: And below is the setup and wiring for this measurement: If I would do it I would use a step down…
user16307
  • 11,802
  • 51
  • 173
  • 312
1
vote
1 answer

Noisy amplifier for HB100 doppler module

I'm working on a doppler radar based on the HB100 module. I want to sample the signal using a microcontroller and display the speed on a LCD. But I want to have the analog front-end working properly first. I built the amplifier recommended in the…
Stelian Saracut
  • 153
  • 1
  • 11
1
vote
1 answer

My printer injects hum into my USB ports

I have a Brother HL-L2305 laser printer. I love it. I also have a pair of KRK Rokit 6 G3 speakers that I run off of an MBox 3. Every time I plug the printer into any USB port, hub or not, a loud hum instantly emits from the speakers until I unplug…
Dominic Luciano
  • 215
  • 3
  • 19
1
2