I had this problem with the remote control receiver in my
audio amplifier. It was false triggering whenever the fan
regulator or switches were operated. The thread where
I discussed this problem is here:
http://www.diyaudio.com/forums/everything-else/177474-remote-control-receiver-unit-problem.html
Although the problem is not there anymore in my new
home as the wiring and the switches seems to be
better. But the weakness in the remote receiver circuit
is there if there was any. So I decided to add the mains
filter circuit suggested by Mooly in the above thread
from the following site:
Audio Mains Filter DIY | DMS Audio
Now that I am getting the 2mH coils done Aucosticraft
told me to be cautious before adding the filter without
much discussion here.
This is the reason I start this thread to ask the audio
community if adding the filter will harm in any way
to any audio equipment. Although Mooly gave me a
go ahead to add the filter. For convenience the circuit
is attached.
Regards
Roushon
audio amplifier. It was false triggering whenever the fan
regulator or switches were operated. The thread where
I discussed this problem is here:
http://www.diyaudio.com/forums/everything-else/177474-remote-control-receiver-unit-problem.html
Although the problem is not there anymore in my new
home as the wiring and the switches seems to be
better. But the weakness in the remote receiver circuit
is there if there was any. So I decided to add the mains
filter circuit suggested by Mooly in the above thread
from the following site:
Audio Mains Filter DIY | DMS Audio
Now that I am getting the 2mH coils done Aucosticraft
told me to be cautious before adding the filter without
much discussion here.
This is the reason I start this thread to ask the audio
community if adding the filter will harm in any way
to any audio equipment. Although Mooly gave me a
go ahead to add the filter. For convenience the circuit
is attached.
Regards
Roushon
Attachments
Hey Roushon,
Now I got your exact problem.
1) In other thread you said you are using you will be connecting to the filter to 15V ie the secondary of transformer. If so please connect it to primary of transformer( guess you are not using smps.) Let me know if you are using smps.
if you are using smps I would recommend you to go for small transformer. the core of transformer itself help in suppressing spikes to some extent. as it cannot respond to spikes of small width.
A simple solution would be buy readymade RFI/EMI suppressor from market. there each costs around 250 to 200 Rs. ( where as you are going to get coil wound for 195 Rs each.)
Try using one such filter available in market. that should greatly ease your job.
a simple solution can be using an X2 cap of 100nf parallel with mov close to primary of transformer should be enough in most cases. if you are using metal chassis don't forget to ground it.
now I have a question, if you make rectification how would you check if the solution works ? you have already shifted.
Do let me know for further discussion.
EBF Series
a typical one.... dont forget to add MOV here.
Now I got your exact problem.
1) In other thread you said you are using you will be connecting to the filter to 15V ie the secondary of transformer. If so please connect it to primary of transformer( guess you are not using smps.) Let me know if you are using smps.
if you are using smps I would recommend you to go for small transformer. the core of transformer itself help in suppressing spikes to some extent. as it cannot respond to spikes of small width.
A simple solution would be buy readymade RFI/EMI suppressor from market. there each costs around 250 to 200 Rs. ( where as you are going to get coil wound for 195 Rs each.)
Try using one such filter available in market. that should greatly ease your job.
a simple solution can be using an X2 cap of 100nf parallel with mov close to primary of transformer should be enough in most cases. if you are using metal chassis don't forget to ground it.
now I have a question, if you make rectification how would you check if the solution works ? you have already shifted.
Do let me know for further discussion.
EBF Series
a typical one.... dont forget to add MOV here.
IR receiver modules are extremely sensitive to power supply noise, and will give off spurious signals when noise is present. The power supply to the IR receiver module should be filtered, but much of the time, it is not. All you need is a series resistor (in the 10's to 100's of Ohm range) on the + supply followed by a bypass cap from + to Gnd. The acutal values are not critical because the module uses very little power (usually << 1 mA) and the noise you are filtering is quite high frequency. Check if your amp has such a filter and if not add one.
Great answer Macboy, thanks for that. Goes right to the heart of the matter 
As to this question:
Most line filters present a high impedance path to noise, that's how they keep it out. But that goes both ways, it can keep it in, too. I know, I've measured it. On a device with a noisy power supply it can be quite dramatic. And anything plugged into the filter with the noisy device it will also see all this trapped noise.
Worse case scenario: You have a noise sensitive device like a phono preamp plugged into the same line filter as a very noisy device like a Class-D power amp. The power filter makes it hard for the noise to drain back out the mains so it backs up into the phono preamp. Without the higher impedance path for noise, at least it would have drained away.
Obliviously, you would not want those two devices to share a filter. But the filter can cause more noise on the AC for just a single device, because the noise can't drain well back into the low impedance mains.
Now I know what you are going to say. "The noise is drained off to ground." Well, yes, it "should" be. But often it ain't. Or if it is, it just ends up polluting the ground - the same ground used by other equipment. So you have to be careful and not assume that the filter is automatically going to kill noise. It may, or it may not. Depends on the filter, your equipment and your mains & ground.
My
As to this question:
Not harm the equipment, but you may end up with more noise than you started with. Why?
Most line filters present a high impedance path to noise, that's how they keep it out. But that goes both ways, it can keep it in, too. I know, I've measured it. On a device with a noisy power supply it can be quite dramatic. And anything plugged into the filter with the noisy device it will also see all this trapped noise.
Worse case scenario: You have a noise sensitive device like a phono preamp plugged into the same line filter as a very noisy device like a Class-D power amp. The power filter makes it hard for the noise to drain back out the mains so it backs up into the phono preamp. Without the higher impedance path for noise, at least it would have drained away.
Obliviously, you would not want those two devices to share a filter. But the filter can cause more noise on the AC for just a single device, because the noise can't drain well back into the low impedance mains.
Now I know what you are going to say. "The noise is drained off to ground." Well, yes, it "should" be. But often it ain't. Or if it is, it just ends up polluting the ground - the same ground used by other equipment. So you have to be careful and not assume that the filter is automatically going to kill noise. It may, or it may not. Depends on the filter, your equipment and your mains & ground.
My
Some manufactures of high power amplifiers recommend plugging the amps directly into the wall outlet.
Why, because the filter acts as a series resistor limiting maximum current (this is the simplified version).
Then obviously the filter isn't large enough, doesn't have enough current capability, capacity.
Yes, I once plugged my 12 amp vacuum cleaner into a 5 amp filtered outlet. It didn't harm the vacuum cleaner at all, but it did melt/toast the 5 amp filter!
Still he asked would it "harm." It might harm the sound, but not likely to harm his equipment.
Yes, I once plugged my 12 amp vacuum cleaner into a 5 amp filtered outlet. It didn't harm the vacuum cleaner at all, but it did melt/toast the 5 amp filter!
Still he asked would it "harm." It might harm the sound, but not likely to harm his equipment.
I doubt it will be more effective or cheaper for a DIYer whose time is free. Parts cost when making your own filter are fairly cheap and its not so difficult to do better than a pre-made one which is just general purpose. Those screened modules do rather rely on having a good quality ground/earth which may not be present. I've started designing my own filter on my blog if anyone here is interested. The aim is to keep the parts cost as cheap as possible and not worry about how long it takes to build. That, and having a design which is relatively independent of the quality of the earth connection.
In regard to the OP's problem though I agree with macboy - deal with the issue at the IR receiver rather than a sledgehammer approach to the whole mains supply. Mains filters are for improving the audio qualilty
<edit> +100 for Pano's point about dirty grounds. That's a killer where anyone's using one of those pre-packaged modules as suggested by Tico_Tico
Last edited:
Always remember that the mains ground is quite often reffered to as "The noise distribution Network" when playing with EMC. Especialy now in the UK with the increasing popularity of Power Line Communications.
Its a pain, but you MUST have a safety earth connection, trouble is it can add noise.
Have a look at the EMC Compliance Club, in their archives (and Bananna Skins section)there are lots of examples covering similar problems.
Its a pain, but you MUST have a safety earth connection, trouble is it can add noise.
Have a look at the EMC Compliance Club, in their archives (and Bananna Skins section)there are lots of examples covering similar problems.
The problem here is line disturbances caused by switch arcing. If the arc happens at the peak of the sine wave the disturbance is greater. Cheap switches and relays are prime offenders.
The filter shown is a cookbook filter mainly intended to keep a noise generating device(SMPS, etc.) from feeding very high frequencies back onto the mains. These filters are generally custom designed around the specific piece of equipment. The filter feeds the noise 'back into the generating equipment'. The inductors in this filter each have a different function depending on how they are 'phased'. One is for common-mode noise and the other for differential-mode noise. The optimum inductor value is dependent on the generating equipment. The capacitor values are critical from a safety standpoint.
An off the shelf filter can be of benefit as long as the current rating is adequate, as stated in a previous post.
As for arcing noise, it will go right through. Best is to supress the arc at the source, such as soft switches, devices that have built in snubbers, etc.
A line conditioner would be the best to put at the front end of the system.
The filter shown is a cookbook filter mainly intended to keep a noise generating device(SMPS, etc.) from feeding very high frequencies back onto the mains. These filters are generally custom designed around the specific piece of equipment. The filter feeds the noise 'back into the generating equipment'. The inductors in this filter each have a different function depending on how they are 'phased'. One is for common-mode noise and the other for differential-mode noise. The optimum inductor value is dependent on the generating equipment. The capacitor values are critical from a safety standpoint.
An off the shelf filter can be of benefit as long as the current rating is adequate, as stated in a previous post.
As for arcing noise, it will go right through. Best is to supress the arc at the source, such as soft switches, devices that have built in snubbers, etc.
A line conditioner would be the best to put at the front end of the system.
I am back
I think the virus already started its work in my body while
I was writing the first post. So forgot to mention two points.
1. When I read about mains filter and it said that this
will block the `dirty current' I thought I am going to
add this to my system. My aim was not to solve
the remote problem as it is not there anymore. Rather
improving my system. I did not know how it will. Now
after reading through the discussions I have a mixed
feeling. It seems it depends on the system if it will
get benefited from the filter or not. Nevertheless I
will try and see as I understand it will not have
any bad effect except probably on the sound quality.
In that case I will remove it.
2. I would like to use the same 2mH CMC in a
power supply circuit for a phono preamp.
The circuit is attached. My circuit will not be exactly
the same but till the ferrite bids. And the diodes will
be some ON semi schottky ones. Do I need a CMC
of some different value for the PS or 2mH is
alright?
Thanks to all for continuing the discussion.
Regarding purchasing a ready made filter, I am
do not like to. Whenever I see a piece of circuit
which I need I like to solder it myself. The smell
of smoking soldering flux is very addicting...
Regards
Roushon.
I think the virus already started its work in my body while
I was writing the first post. So forgot to mention two points.
1. When I read about mains filter and it said that this
will block the `dirty current' I thought I am going to
add this to my system. My aim was not to solve
the remote problem as it is not there anymore. Rather
improving my system. I did not know how it will. Now
after reading through the discussions I have a mixed
feeling. It seems it depends on the system if it will
get benefited from the filter or not. Nevertheless I
will try and see as I understand it will not have
any bad effect except probably on the sound quality.
In that case I will remove it.
2. I would like to use the same 2mH CMC in a
power supply circuit for a phono preamp.
The circuit is attached. My circuit will not be exactly
the same but till the ferrite bids. And the diodes will
be some ON semi schottky ones. Do I need a CMC
of some different value for the PS or 2mH is
alright?
Thanks to all for continuing the discussion.
Regarding purchasing a ready made filter, I am
do not like to. Whenever I see a piece of circuit
which I need I like to solder it myself. The smell
of smoking soldering flux is very addicting...
Regards
Roushon.
Attachments
Hi Roushan, Sure virus couldn't stop you from checking thread. Sure you will get well soon.
Now,
1) The coil you have shown here would cancel common mode noise. The missing part is start and end of the winding.
2) when you change speed of fan or switch fan on or off, the coil typically generates back EMF and this is the root cause of spurious trigger.
3) This can be suppressed using MOV / X2 cap / snubber circuit.
4) other experiment I would suggest is remove the IR sensor module. Check if spurious trigger exists. I mean get exactly which part of circuit is culprit.
Now,
1) The coil you have shown here would cancel common mode noise. The missing part is start and end of the winding.
2) when you change speed of fan or switch fan on or off, the coil typically generates back EMF and this is the root cause of spurious trigger.
3) This can be suppressed using MOV / X2 cap / snubber circuit.
4) other experiment I would suggest is remove the IR sensor module. Check if spurious trigger exists. I mean get exactly which part of circuit is culprit.
I went looking for the spec sheet for that 2mH part. The only thing I could find was some mechanical data, nothing electrical. So in the absence of some hard characterisation, I can't recommend you use it. Find something that has a published response curve or alternatively build your own with known performance parts (core and wire). In any case that choke is rated for much higher current than is optimal for a preamp.
Over on my blog I've put up a frequency response curve for a family of CM chokes which are better than the run of the mill, by virtue of having a segmented winding which reduces self-capacitance. Even then, all of them do worse than 40dB rejection above 3MHz. The more common type with single windings are around 10dB worse than this at HF.
use of series resistors - also valid
I have recently had very good results using a RC mains filter. Of course the applications are best restricted to devices that dissipate a constant power - such as a class A preamp or DAC. I built a filter recently with a couple of 100 ohm 5W resistors in series with A and N followed by a MKP suppression cap. There was 8V dropped but the mains here is high to start with so this brings it back down to where it should be. I saw a nice reduction of HF noise on the scope. Filters such as this might be a cheap solution - to be added to individual constant VA devices to remove locally generated noise - from high power linear PSU's as well as SM PSU's.
I have recently had very good results using a RC mains filter. Of course the applications are best restricted to devices that dissipate a constant power - such as a class A preamp or DAC. I built a filter recently with a couple of 100 ohm 5W resistors in series with A and N followed by a MKP suppression cap. There was 8V dropped but the mains here is high to start with so this brings it back down to where it should be. I saw a nice reduction of HF noise on the scope. Filters such as this might be a cheap solution - to be added to individual constant VA devices to remove locally generated noise - from high power linear PSU's as well as SM PSU's.
I'm currently playing with iron wire for making chokes - its considerably cheaper than copper and is nicely resistive. With its lower skin depth it gets even more lossy as the frequency goes up. I'm getting highly worthwhile improvements in soundstage depth and decay tails seem to go on forever...
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