Stereo Speakers “Hum”

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powerplay

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Hello all,

After installing a separate circuit from an basement subpanel for an older “Technic” Amplifier, it has been discovered that the LED lighting on an opposite phase from the amplifier home circuit with Lutron Dimmer is causing “hum” on the speakers, as the sound does disappear when the Lowe’s LED lights are off.

I presume it is “harmonics” from Solid State dimmer and lighting ?

Is there something simple that can be done to remedy this issue ?

Thank you for any feedback !
 
Does the level of hum change when you disconnect all audio inputs to the amplifier? Is this an "integrated amplifier" including a preamp, volume control, etc, and if so does the hum change with the volume knob? Or does it require a higher level input like around 1Vrms to reach rated power?
 
Tell use about the music sources?
Do they need to be connected for the hum to happen.
Normal troubleshooting.
Start with amp and speaker, other interconnects an AC power unplugged.
The plug in one unit's interconnects and AC power.
Continue
 
somewhat related story. LED lights can cause havoc on other electronics.

for months my garage door opener was driving my wife and i crazy. when we would use the remote open button on our car or the remote that came with the opener, it would only work reliably when we got home. but when we were leaving the house, the button would work 1/20 times so we would have to get out of the car and press the button in the garage. it took the longest time to realize that the issue was only present when the light bulb was on.

Months before, I had gone through most of my house and installed LED bulbs, including the garage door motor housing. we removed the light bulb and installed an incandescent. never saw the issue again.

Had a similar issue with using an "incompatible" light bulb with a lutron caseta smart dimmer. the light bulb was always on, but the dimmer was non-functional. I was driving myself crazy trying to check the wiring over and over. Changing light bulbs resolved the issue.

all of this to say, try a different brand/make/model of light bulb, or go straight incandescent.
 
By far, the most common dimmer is the "forward phase" type where the output voltage waveform has a fast risetime when it turns on at a selected time during the AC cycle. That can cause relatively large current spikes to be drawn by the capacitors of the driver circuitry inside of LED lights, leading to possible interference issues with audio equipment, etc. One suggestion is to try a dimmer that has "reverse phase" capability, where it turns on at the begining of the AC waveform when the voltage is close to zero, and it turns off later in the waveform. This would produce much smaller current spikes with capacitive loads like LED lights (but it wouldn't be suitable for inductive loads like transformers). The Legrand RH703PTUTCCC4 ia a dimmer that allows the selection of either forward or reverse or phase dimming.

https://www.amazon.com/Legrand-radi...ocphy=9021470&hvtargid=pla-350875867143&psc=1

Another suggestion is to plug the amplifier into a power strip that has low-pass filtering. For example, an Isobar unit from Tripp Lite.
 
Last edited:
powerplay said:
Hello all,

After installing a separate circuit from an basement subpanel for an older “Technic” Amplifier, it has been discovered that the LED lighting on an opposite phase from the amplifier home circuit with Lutron Dimmer is causing “hum” on the speakers, as the sound does disappear when the Lowe’s LED lights are off.

I presume it is “harmonics” from Solid State dimmer and lighting ?

Is there something simple that can be done to remedy this issue ?

Thank you for any feedback !
Click to expand...
If I may, what type of humming did you hear? (not to confuse with one not knowing the lyrics, which a joke)
I recommend putting off suspected electrical equipment one by one for good measure. As mentioned, ferrite bead/ noise filters are available. Best bet, Google "ferrite beads" or clamp-on noise filters.
 
drktmplr12 said:
somewhat related story. LED lights can cause havoc on other electronics.

for months my garage door opener was driving my wife and i crazy. when we would use the remote open button on our car or the remote that came with the opener, it would only work reliably when we got home. but when we were leaving the house, the button would work 1/20 times so we would have to get out of the car and press the button in the garage. it took the longest time to realize that the issue was only present when the light bulb was on.

Months before, I had gone through most of my house and installed LED bulbs, including the garage door motor housing. we removed the light bulb and installed an incandescent. never saw the issue again.

Had a similar issue with using an "incompatible" light bulb with a lutron caseta smart dimmer. the light bulb was always on, but the dimmer was non-functional. I was driving myself crazy trying to check the wiring over and over. Changing light bulbs resolved the issue.

all of this to say, try a different brand/make/model of light bulb, or go straight incandescent.
Click to expand...
This is known by Genie garage door openers, they sell a led bulb for their door openers because of this. Must have additional filtering.
 
mopowr steve said:
This is known by Genie garage door openers, they sell a led bulb for their door openers because of this. Must have additional filtering.
Click to expand...
Chamberlain/Liftmaster also recommend (their own brand of course) special LED lamps for their garage door openers. I guess the Craftsman openers also will need the lamps as they're re-badged Chamberlain units. Odd, Chamberlain says you can use up to 26 watt CFL's, if you can find them.
 
drktmplr12 said:
somewhat related story. LED lights can cause havoc on other electronics.

for months my garage door opener was driving my wife and i crazy. when we would use the remote open button on our car or the remote that came with the opener, it would only work reliably when we got home. but when we were leaving the house, the button would work 1/20 times so we would have to get out of the car and press the button in the garage. it took the longest time to realize that the issue was only present when the light bulb was on.

Months before, I had gone through most of my house and installed LED bulbs, including the garage door motor housing. we removed the light bulb and installed an incandescent. never saw the issue again.

Had a similar issue with using an "incompatible" light bulb with a lutron caseta smart dimmer. the light bulb was always on, but the dimmer was non-functional. I was driving myself crazy trying to check the wiring over and over. Changing light bulbs resolved the issue.

all of this to say, try a different brand/make/model of light bulb, or go straight incandescent.
Click to expand...

synchro said:
By far, the most common dimmer is the "forward phase" type where the output voltage waveform has a fast risetime when it turns on at a selected time during the AC cycle. That can cause relatively large current spikes to be drawn by the capacitors of the driver circuitry inside of LED lights, leading to possible interference issues with audio equipment, etc. One suggestion is to try a dimmer that has "reverse phase" capability, where it turns on at the begining of the AC waveform when the voltage is close to zero, and it turns off later in the waveform. This would produce much smaller current spikes with capacitive loads like LED lights (but it wouldn't be suitable for inductive loads like transformers). The Legrand RH703PTUTCCC4 ia a dimmer that allows the selection of either forward or reverse or phase dimming.

https://www.amazon.com/Legrand-radi...ocphy=9021470&hvtargid=pla-350875867143&psc=1

Another suggestion is to plug the amplifier into a power strip that has low-pass filtering. For example, an Isobar unit from Tripp Lite.
Click to expand...

There are many variations of LED ballast design. Radiated, audible and conducted noise are entirely dependent on the LED ballast design.
The cheapest of the lamps use a series rheostat linear ballast placed ahead of the string of LED elements whose combined forward voltage is a smidge below the input line voltage and modulates the MOSFET/transistor (essentially an electronically controlled rheostat). These are the quietest type, but often have very poor output regulation in response to line voltage variations and incidents.

Lamps using resistive linear LED ballasts for 230v have twice as many LEDs in series as those made for 120v countries.

Get a few different varieties of cheapest bulbs, such as those from the dollar store. Smash them open. The ones with the most simplistic circuits is the resistive ballast. It is evident from the lack of any inductive components. You'll just see a few surface mount blobs, a capacitor and nothing else aside from the LED elements.

The ones that cause RFI and buzzing are the ones that utilize switch mode design in the ballast.
 
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