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AC incoming signal passes on to speakers

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Hi all,

I thought i share some thoughts here, on my current dillema.:D

I noticed i must have a pretty noisy AC line when some transformers started buzzing ( in my previous house, none did).
So i went on and tried to solve this as i could, with DC block filters and most recently a PS AUDIO Premier : an AC regenerator.
This product converts the incoming AC signal to DC, and then regenerates a new "clean" AC wave at 230V. It has a monster 1.2kVA toroid in it.
I removed all electronics from the "stereo" line. Only audio products are connected to this fuse box jumper.

Fast forward, i thougt this would solve all AC problems. It does not.
The following is a description of my system connections:

AC wiring >> PS AUDIO regenerator >> MAYA >> Speakers

All the other components (Processor, PRe-amp, other power amps) are also connected to this PS AUDIO.

Problem :

Whenever i turn ON or OFF my electric blinds (curtains) i get a sharp loud sound from the speakers. Like a burst of noise introduced in the line.
This only last for a fraction of a second (when turning ON or OFF).

Still, how would the electric motor for the curtains induce so much noise in the AC line, that this is carried on through the AC regenerator, through the MAyas....onto the speakers?

PS. I may need to test if the noise is coming directly in the MAya through the AC , or through the RCA !? Still..... strange.

What are your thought on this ?
Cheers
SAF
 
Hi all,

I thought i share some thoughts here, on my current dillema.:D

I noticed i must have a pretty noisy AC line when some transformers started buzzing ( in my previous house, none did).
So i went on and tried to solve this as i could, with DC block filters and most recently a PS AUDIO Premier : an AC regenerator.
This product converts the incoming AC signal to DC, and then regenerates a new "clean" AC wave at 230V. It has a monster 1.2kVA toroid in it.
I removed all electronics from the "stereo" line. Only audio products are connected to this fuse box jumper.
Cheers
SAF

It is nice that you now have that nice PSAudio regenerator for your audio AC and can only make the audio system better.
But it looks to me like you could use an electrician to come out and give an assessment on isolating the curtain motors so as not to interfere with the audio system. There should be several different options for doing this and they all pretty much require an electrician to properly perform the tasks.
 
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Filipe,

All good advice, and thanks for the responses.

I think the interference is AC, nothing more, because it only appears when an AC (induction?) motor switches on.

Accordingly, a 0.05uF 250VAC self-healing polypropylene AC suppression cap should fix it.

This will squelch ('short') the AC emission from the running AC motor.

Next step, if this does NOT work, would be to put in a snubber across the primaries of the amp toroids, but it really is best to remedy the issue at source if possible.

Ciao,

Hugh
 
Thank you all for the positive inputs.

I understand a bit of electrics and i know the best practice is to isolate at the source. Still, i noticed this electric motor curtains are not the only noisy appliance i have. My dish washer makes the PS AUDIO regenerator go bezerk !
When the dishwasher starts or stops, the AC regenerator starts switchin into protection mode, and the display jumps from 3% THD to 7% or 8% !!
But no noise from speakers when dishwasher is in motion.

I am not "bothered" with the electric motor curtains so much. I only actuate them 1 or 2 times per day....so this is not sufficient to start fidling with them.

Still...even with the RF induced in the AC line...how is it that the AC regenarator or the Power Supply from the Maya, do not filter them out?

The electric motor does not have an easy access. The only indoor part is the switch and could be a 1 pole switch so the cap is no good there. Must take the switch apart and confirm. And because its in WALL, i may not have the space to fit a cap.

The dishwhaser could be plugged in through an EMI/RFI noise blocker.
I will look into that.
 
Correction:

I was under the impression the recommended 0.05uF cap would be N and F ( silly).
With only the F available at the switch for the curtains, i believe i can acommodate it.
I must take it apart and check.
Should 2 caps be used ? One for Live and one for Neutral, or if the switch is single pole, only that one should take the cap?

Cheers
 
Correction:

I was under the impression the recommended 0.05uF cap would be N and F ( silly).
With only the F available at the switch for the curtains, i believe i can acommodate it.
I must take it apart and check.
Should 2 caps be used ? One for Live and one for Neutral, or if the switch is single pole, only that one should take the cap?

Cheers

If you are unsure of what you are doing, stop right NOW.
While getting an electrician in may not be as easy as writing some words, trying to get one to come look might be the best option.
 
Filipe,

Some audio amps use a 0.22uF self-healing 250VAC poly across the two primary supplies, often in series between active and neutral with a 10R 1W flameproof resistor.

This will extract much of the AC noise over and above the 50/60Hz mains which is finding its way into the speaker. But I'm actually surprised this gets through the PS filter supply, and I'm wondering if this might also be radiated EMI. It's a bit odd to me, I will think on this more.

Hugh
 
Saf


Strange things happening in Porto...It is normal to hear a "tchak" or "pum" when switching things. Remember "... This apparatus must accept ...interference ... in the manuals..."
I live in Santo Tirso (20Km away) and I don't have those problems at home. Well sometimes my computer UPS trips due under-voltage... I would call an electrician to check Your wiring. What You can do is to verify if the cables in the wall are all tight fastened on the outlets and if the fasteners on the fuses (GFI) are also tight. Sometimes they want to sell apartments fast and work ugly...
By the way, nominal Voltage in Portugal is 230 (L-N) /400 (R-S-T) V.+-10%, but I know a place (wedding farm) where one phase carries only 180V.


Try a capacitor between the contacts (Just one). I believe it's arcing noise. You could also try filtered multi-outlets ("triplas"). The only appliance that upsets my house wiring is a 1500W Xenon disco strobe and You hear the UPS howling.
 
Ahah ! Yes strange things happen in Porto, but most are due to Wine consumption :)

Thank you all for the inputs. I ordered an EMI filter plug for the dishwasher machine (simple plug and play), plus a couple of 0,047uF caps for the switches on the electric curtains. Lets see what happens!

My voltage oscilates between 229v - 236v during the day, but never lower than that.
 
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