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Questions tagged [hum]

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Mains hum in TDA7265-based active loudspeaker

The old pair of M-Audio Studiophile AV40 active speakers (one box containing all the amplifier parts and the second is just a passive box) I have have developed a clear low-frequency hum. This hum is ...
paulus's user avatar
  • 1
2 votes
0 answers
29 views

Why the induced noise is sometimes additive but sometimes works as a constant?

Why sometimes the noise (e.g., induced 50hz hum) is added to a useful signal (thus increasing its 50hz value), but sometimes it works as a noise floor - has a static value and can be overpowered by a ...
Matilda Bentefor's user avatar
1 vote
0 answers
43 views

Alternate values of high pass filter isn't working, even though gain, phase & transient response is almost same

I'm trying to design a high pass filter to remove the humming noise (around 50-60Hz.) If I use alternate values, it's not working. It's the recommended value from a YouTube video (470pF, 5.6Mohm.). ...
Santhosh Kumar H O's user avatar
2 votes
2 answers
87 views

Hum without ground loop

I have an audio measurement system. The system is connected to and powered by a laptop. The system has no other connection to the AC grid. Now, if the laptop is connected to the AC grid and i measure ...
herrzinter's user avatar
0 votes
1 answer
108 views

Locating the source of a persistent 120 Hz hum in amplifier

I'm working on rebuilding a subwoofer amplifier. The caps have been replaced, the corroded press-on tabs for transformer and speaker connections have been replaced. Upon reassembly, the amplifier ...
casoundman's user avatar
0 votes
2 answers
351 views

Loud hum when input is connected to amp

I've just built a JLH 1969 amplifier kit that I bought online. When connected to the stereo output of my phone (isolating one channel at a time) the amp works fine one channel at a time but when I ...
Ahsan's user avatar
  • 143
0 votes
1 answer
473 views

Grounding Li-ion battery pack to stop amplifier hum

I'm trying to connect a tube guitar amplifier to the Delta 1300 W battery pack by Echo Flo. The pack is not grounded, so I get a hum. Echo Flo suggested connecting the amp to a power strip, then ...
Island's user avatar
  • 9
3 votes
2 answers
579 views

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 ...
Discord Warrior's user avatar
0 votes
2 answers
248 views

Subwoofer hums when no audio source is connected [closed]

The hum stops as soon as an audio source is connected or any metal part of the subwoofer is connected to the ground of a socket. Does anyone have any idea what the problem is?
sapes's user avatar
  • 1
1 vote
0 answers
43 views

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 ...
Zenvir's user avatar
  • 11
0 votes
1 answer
194 views

Guitar Amp Humming (interference?)

So my amp worked perfectly fine in my old setup in another part of the house, but in my new setup it buzzes when I connect a cable, and with a guitar. I thought it was a grounding issue, but it didn't ...
user11779's user avatar
1 vote
1 answer
705 views

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 ...
Per Jessen's user avatar
0 votes
1 answer
615 views

I have a single phase induction motor, with no capacitor, and can't see the shaded pole. Can you help me understand how it starts or should start?

I have a small single phase, induction motor with no capacitor. It's not missing, so this has got me thinking it should be a shaded pole. However, I don't see the shaded pole and my motor is just ...
Preston's user avatar
  • 103
0 votes
1 answer
629 views

why does household ceiling fan electric motor hum?

I'm interested in the technical reasons behind why an inexpensive ceiling fan in a home would hum, such that when in your bedroom above your bed on low speed is annoying. Is there a better type of ...
ron's user avatar
  • 141
6 votes
2 answers
2k views

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. ...
Avid Pro Tool's user avatar
12 votes
7 answers
13k views

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 ...
Willis Blackburn's user avatar
1 vote
1 answer
2k views

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 ...
Chupacabras's user avatar
  • 5,508
2 votes
1 answer
1k views

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 ...
mrkefca's user avatar
  • 71
0 votes
1 answer
422 views

Plus, Minus, Ground and the damn noise

I am a relatively newbie here and I am trying to build this project... so do not kick me hard and forget any stupid errors you see on the project. I appreciate any suggestions, criticism, etc., ...
Duck's user avatar
  • 847
0 votes
1 answer
112 views

Getting rid of charge injection click and hum sound on this switch I have designed

I have designed this 4 stereo channel TRS switch. You have 4 channel stereo input and 1 stereo channel out. You press a button and you switch which channel you want to send to the output. Once the ...
Duck's user avatar
  • 847
1 vote
0 answers
394 views

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 ...
user16307's user avatar
  • 12.2k
1 vote
1 answer
4k views

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 ...
Stelian Saracut's user avatar
5 votes
2 answers
5k views

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):...
abc's user avatar
  • 639
4 votes
1 answer
1k views

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 ...
cubix's user avatar
  • 233
0 votes
2 answers
405 views

How good should the regulated AC/DC power supply filter be in tube headphone amp?

I am building a tube headphone amplifier. I built a AC/DC regulated power supply (220v AC to ~250v DC) but I am not sure about how good is the filter. The filter contains 120uF and 68UF capacitors, in ...
Giedrius's user avatar
  • 365
0 votes
1 answer
665 views

eliminating audio hum

I'm working on a circuit that feeds a microphone into the ADC of the STM32F4 Discovery and then outputs that exact signal out of the microcontroller's DAC and then to a headphone jack. I am able to ...
NoahPena7's user avatar
0 votes
1 answer
2k views

Remove mains hum out of amplifier

I have a headphone amplifier that is afflicted by mains hum 50 Hz and upper harmonics, below is an FFT of the spectrum with nothing connected to its inputs. In headphones you can clearly hear a buzz-...
ebbmme's user avatar
  • 11
1 vote
1 answer
314 views

My printer injects hum into my USB ports [closed]

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 ...
Dominic Luciano's user avatar
4 votes
1 answer
2k views

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 ...
Giedrius's user avatar
  • 365
2 votes
3 answers
1k views

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 ...
Stefan's user avatar
  • 209
0 votes
1 answer
713 views

Hum Cancelling Circuit

Consider the following circuit: I was just thinking about how connecting consumer grade unbalanced electronics together has a tendency to generate hum. For example, I have a little mixer that has an ...
squarewav's user avatar
  • 1,461
2 votes
3 answers
8k views

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 ...
Coliban's user avatar
  • 226
1 vote
2 answers
2k views

How to remove mains hum from a BNC cable?

BNC cables are used as inputs to a data-acquisition hardware. If long BNC cables are picking up the 50/60Hz mains hum through the air like antenna, how can I filter this? Would connecting the BNC ...
user16307's user avatar
  • 12.2k