It seems at least some people mean (partly) the same but fail to express so. Please reread posts and come to the conclusion of agreement. Otherwise the quarreling/polluting won't make the common point any clearer. The common point being that separated mains plugs meant to "purify" mains voltage are not to be recommend unless one wants to just spend money and feel an improvement.
You are mixing your MOV's with your filters 😆
Yes, an ATX power supply for example does have an MOV protection on it, i already said that, and of course the MOV it directly connected across the mains, that's how it works. But it does have a proper fuse near it and in series with the mains to it, so that when the MOV does clamp and shorts out the mains, it will go up in smoke but it will also blow the fuse, thus cutting the mains feed to it and to that ATX unit.
The EMI filter is what is in series with the load, what it mainly does is protecting the mains from the switching noise ( and other load noise ), but it can also filter some noise already on the mains. So it does work both ways but only because it is inserted between the load and the mains, and any mains filtering that is does do, it's for that load with which is in series with only, meaning the mains noise is still there in the wall plug, but that one load does not see it because of the filter.
Anyway, i see i am wasting my time here, as i said, electronics is learned from books and good teachers at school, not on the forum!
That's just it, @NareshBrd really thinks that improvement is actually there.
I am trying to explain that this is only in his mind but without mush success, and i am done here.
Read my posts again
I do have fuses in series...
The question of noise is made further complex with SMPS, and Class D.
Then we have to consider each case.
My answer was a basic type of filter design.
Which is not needed by coffee makers, or clothes irons, for example.
I do have fuses in series...
The question of noise is made further complex with SMPS, and Class D.
Then we have to consider each case.
My answer was a basic type of filter design.
Which is not needed by coffee makers, or clothes irons, for example.
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Well my coffeemaker makes better tasting coffee with a mains filter!
Just joking, please stop the quarreling.
Just joking, please stop the quarreling.
Hello Everyone,
Thank you for sharing but I don't mean to start this threat ending up an argument.
I now get the point very clear, that best to use a proper filter in series of the equipment.................👍
Thank you for sharing but I don't mean to start this threat ending up an argument.
I now get the point very clear, that best to use a proper filter in series of the equipment.................👍
It is. One has to adapt the filter to the device with regards to current, maximum power etc. Devices with built in SMPS may need closer examination as these often already have mains filters.
Simplest and quite effective are good quality IEC mains inlets with built in fuse and filter. Some have a mains switch too which may come handy when the device has no true power off possibility. You'll learn the art of filing a nice hole in the casing too 🙂 Remove the back cover if possible. Make sure to stick clear tape at both sides of the cover to avoid scratches and debris flying around. First drill holes close to eachother and then file your hole as perfect as you can. Deburr edges, paint the bare metal to avoid corrosion and make sure to connect the PE wire the right way to chassis (class I devices). There is more to this with regards to Audio GND and PE but that is outside the scope of this thread I think. In case there already is an IEC inlet or mains cable with PE pin/wire you almost can't go wrong.
Another possibility is building a mains distributor with mains filter, power switch etc. solely for audio devices. My Fritz is such an example. Not the most optimal solution but you won't loose a nights sleep over "resale value" and such non items. A shared filter still is better than no filter when mains voltage is not clean. Debatable, I know.
In all cases:
1. DIYing a mains filter is not to be recommended with X and Y caps and direct mains connections.
2. Only do work in this area if you know what you are doing and are aware of possible issues/risks.
3. Work safe and tidy and crimp rightly sized connectors instead of soldering.
4. Insulate any bare wire end and think with every connection of possible risk of touching.
5. Check, check again and check another time before plugging stuff in.
Simplest and quite effective are good quality IEC mains inlets with built in fuse and filter. Some have a mains switch too which may come handy when the device has no true power off possibility. You'll learn the art of filing a nice hole in the casing too 🙂 Remove the back cover if possible. Make sure to stick clear tape at both sides of the cover to avoid scratches and debris flying around. First drill holes close to eachother and then file your hole as perfect as you can. Deburr edges, paint the bare metal to avoid corrosion and make sure to connect the PE wire the right way to chassis (class I devices). There is more to this with regards to Audio GND and PE but that is outside the scope of this thread I think. In case there already is an IEC inlet or mains cable with PE pin/wire you almost can't go wrong.
Another possibility is building a mains distributor with mains filter, power switch etc. solely for audio devices. My Fritz is such an example. Not the most optimal solution but you won't loose a nights sleep over "resale value" and such non items. A shared filter still is better than no filter when mains voltage is not clean. Debatable, I know.
In all cases:
1. DIYing a mains filter is not to be recommended with X and Y caps and direct mains connections.
2. Only do work in this area if you know what you are doing and are aware of possible issues/risks.
3. Work safe and tidy and crimp rightly sized connectors instead of soldering.
4. Insulate any bare wire end and think with every connection of possible risk of touching.
5. Check, check again and check another time before plugging stuff in.
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I forgot, MOVs are excellent transient suppressors, and have been replaced in some cases by TVS devices, Transient Voltage Suppressors, possibly a class of diodes, IIRC.
But please heed the advice above from Jean-Paul, do not do something you are not confident about.
I hope I spelled his name properly...
But please heed the advice above from Jean-Paul, do not do something you are not confident about.
I hope I spelled his name properly...
I've build one & this only works well if you load it up with a 100 watt big resistor or incandescent bulb as stated in the article
I always thought the very idea of 'needing' a constant, resistive 100W load for the JRisch idea is staggeringly, unforgivably -wasteful. Also revealing of a totally -1/2-arsed 'design.' It was one of those prompts that led me to inquire / learn further. To realise it only takes a very- little-more analysis (for any comparable device) to only-roughly sim supply and load-side impedances, find the grossest resonances, and then ...funny how easy it is to finesse how to damp, or disrupt them, ...effectively for free by selecting the components for their own parasitics! The schematic , is never the territory: the component, is never perfect ...
I digress, to reinforce the point made better, earlier, by others:
This sort of thing is why - exactly why - as our esteemed Jean-Paul suggests ... just buy a manufactured, SAFE, self-contained, warranted one from Schaffner or equiv: of only -just-enough capacity - when it will work perfectly-well-enough, cheaply - and very essentially: Safely - for a very long time. You will not beat parts-price: performance: effort:lifespan - at all.; & never match the safety qualifications on such off-the-shelf parts.
-And ffs, not need to waste 100w 'to damp it'
I digress, to reinforce the point made better, earlier, by others:
This sort of thing is why - exactly why - as our esteemed Jean-Paul suggests ... just buy a manufactured, SAFE, self-contained, warranted one from Schaffner or equiv: of only -just-enough capacity - when it will work perfectly-well-enough, cheaply - and very essentially: Safely - for a very long time. You will not beat parts-price: performance: effort:lifespan - at all.; & never match the safety qualifications on such off-the-shelf parts.
-And ffs, not need to waste 100w 'to damp it'
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[I went to edit to add this, but ran out of time:]
ETA:
here is just one, or two reasons why the idea of a steady 100w load is a nonsense / indicative of lousy design understanding and recommendation:
So - you can use a big dumb 100w load; and pay for that loss (ouch!)
or
.. note that the rest of the civilised world doesnt use a 100w bulb or resistor: but uses little integrated 'snubbers' which are usually (appropriately certified to local National requirements) c.100nF+100ohm in series in a single small thing that looks like a capacitor, but ful UL/AC- mains voltage rated. These provides ALL the 'damping' ever required, because there is no need for the damping to extend any nearer to LF, let alone -DC
- and such things are sold cheaply in a single 2-lead integrated packages the world over for dealing with removing click effects from thermostats switching etc, and typically tens of cents to buy, last forever, and ... they waste zero power. They just work reliably to calm the realm above c 10-15Khz, where reactive filters are usually under-damped.
ETA:
here is just one, or two reasons why the idea of a steady 100w load is a nonsense / indicative of lousy design understanding and recommendation:
- This example filter was based on nom. 110VAC mains; so '100w' load is essentially - about 100- 110ohms.
- The nominal low-RF impedance of 'Romex' / 3core Fixed AC mains Wire) -style cables , is about 100-110 ohms
- (NB - this does not depend on US use, its about the same the World over - just an artifact of domestic AC wiring geometry)
- that range around 100ohms, +/-50% is what 'mains filters' are designed around. Undamped.
So - you can use a big dumb 100w load; and pay for that loss (ouch!)
or
.. note that the rest of the civilised world doesnt use a 100w bulb or resistor: but uses little integrated 'snubbers' which are usually (appropriately certified to local National requirements) c.100nF+100ohm in series in a single small thing that looks like a capacitor, but ful UL/AC- mains voltage rated. These provides ALL the 'damping' ever required, because there is no need for the damping to extend any nearer to LF, let alone -DC
- and such things are sold cheaply in a single 2-lead integrated packages the world over for dealing with removing click effects from thermostats switching etc, and typically tens of cents to buy, last forever, and ... they waste zero power. They just work reliably to calm the realm above c 10-15Khz, where reactive filters are usually under-damped.
EMI and other filters are a ready item, as above.
I would suggest a mildly higher rating than the equipment, partly as factor of safety, and partly due to the fact that you might add or change equipment in that circuit, so then you need not have to change the filter.
As always, follow safety codes and practices, over protection is better than low protection.
I would suggest a mildly higher rating than the equipment, partly as factor of safety, and partly due to the fact that you might add or change equipment in that circuit, so then you need not have to change the filter.
As always, follow safety codes and practices, over protection is better than low protection.
You are confusing many things yourself. If you call people stupid, nobody know how and what to call you.
In industry, equipment like variable frequency drives produce lots of harmonics. Large line (harmonic) filters are used to reduce the harmonic currents passing back in to the mains. There are other industrial devices that are fitted with such filters.
But in audio, the mains supply is more dirty and filters are used to reduce the interference getting through the power supply.
Depends on where you live, the spikes in the mains supply do harm to devices inside the house and there is nothing wrong in fitting a MOV to reduce the effect. If there is some welding shop nearby, you will need something fitted in your house.
Regards.
A friend damaged the PLC on a molding machine. as it was in the same shop as his spot welding machine, and with every weld the current drawn would cause one phase to go low.
Ultimately, he shifted both machines to different shops, fed from different transformers.
Had to replace the PLC, he put fast reaction voltage regulators (IGBT driven) on all his molding machines after that incident.
They have harmonic filters, EMI filters, high and low voltage cut offs, response time is 15 milliseconds.
Really, you should not consider other people incompetent, experience counts.
Ultimately, he shifted both machines to different shops, fed from different transformers.
Had to replace the PLC, he put fast reaction voltage regulators (IGBT driven) on all his molding machines after that incident.
They have harmonic filters, EMI filters, high and low voltage cut offs, response time is 15 milliseconds.
Really, you should not consider other people incompetent, experience counts.
In my area, lightning is common. Also all my neighbors have arc-welders. The power company has some crap-absorption, if only by virtue of size (miles of wire and tons of transformers to absorb crap). But in my last house I lost a lot of gear from lightning.
I have a certified "MOV" unit in my fusebox. Square D Homeline 22.5 kA 2-Pole SurgeBreaker. Sales-sheet. I mounted it near the main (input) breaker so it is the first thing a surge sees: an easy way to go to ground, before it sees my appliances and lamps. I supplement that with MOVs in a certificated surge-strip at the PC.
Yes, everything is a series-parallel pair. The 'SurgeBreaker' works against the series impedance of my feeder from the street: about 0.4r resistive and 0.3r inductive. This is an order of magnitude higher than the 'SurgeBreaker' arc-over impedance so it takes the edge off. The PC surge strip works against the 50' of circuit wire, and may add a mild suppression to stuff plugged-in on the same circuit. (I don't figure full suppression for anything a few feet away.)
Since this 'SurgeBreaker' is IN my house and under my bedroom stairs, I was very concerned that it not burn-down the house. Not only is this all UL listed, the maker Square-D is active in improving electric safety. Also it is "behind" my 100A main breaker, and has internal fuses (with LED monitors). I realize that IF it gets a major hit, it will probably "bomb", but the case material and my rated fusebox will contain the fire and shrapnel.
Does it make my well-water taste better?
I have a certified "MOV" unit in my fusebox. Square D Homeline 22.5 kA 2-Pole SurgeBreaker. Sales-sheet. I mounted it near the main (input) breaker so it is the first thing a surge sees: an easy way to go to ground, before it sees my appliances and lamps. I supplement that with MOVs in a certificated surge-strip at the PC.
Yes, everything is a series-parallel pair. The 'SurgeBreaker' works against the series impedance of my feeder from the street: about 0.4r resistive and 0.3r inductive. This is an order of magnitude higher than the 'SurgeBreaker' arc-over impedance so it takes the edge off. The PC surge strip works against the 50' of circuit wire, and may add a mild suppression to stuff plugged-in on the same circuit. (I don't figure full suppression for anything a few feet away.)
Since this 'SurgeBreaker' is IN my house and under my bedroom stairs, I was very concerned that it not burn-down the house. Not only is this all UL listed, the maker Square-D is active in improving electric safety. Also it is "behind" my 100A main breaker, and has internal fuses (with LED monitors). I realize that IF it gets a major hit, it will probably "bomb", but the case material and my rated fusebox will contain the fire and shrapnel.
Does it make my well-water taste better?
A couple ideas not yet mentioned. Sola (example https://www.ebay.com/itm/273250468386) make, or used to make, these "constant voltage transformers" which provided a more or less constant output voltage, against varying input line voltage. They did this using a "ferro-resonant" transformer, which is a transformer having a third winding connected to an oil filled cap, which together resonates at 50 or 60 Hz. So it's like an isolation transformer with a bandpass filter built into it. My guess is, no little voltage twiddles on the input from other stuff is going to make it past that filter.
If the use case isnt powering something like a pair of Carver Silver 7s, one would think generating your own AC from a spare amplifier, oscillator (used to be a chip and a crystal) and a power transformer run in reverse would give you the purest AC ever. Such a scheme would probably only power a preamp...
My last thought is there's probably a battery backup device that outputs a true sine wave for long enough to be useful for a listening session. Again, probably wont run the power amplifiers, but could be effective on more sensitive, upstream equipment. Looks like "PS Audio" has already made a purpose built device that provides 1500W of pure AC in the form of a BBU. Not cheap, even used https://www.ebay.com/itm/174508141538 but such a solution has been already commercialized for the audio market.
Looks like Westinghouse has a whole series of such devices, powered by lithium ion batteries, example https://www.homedepot.com/p/Westing...LED-Display-and-Flashlight-iGen600s/315510546
Have to believe the output of one of those would have less voltage artifacts than the dirty 'ol AC mains.
If the use case isnt powering something like a pair of Carver Silver 7s, one would think generating your own AC from a spare amplifier, oscillator (used to be a chip and a crystal) and a power transformer run in reverse would give you the purest AC ever. Such a scheme would probably only power a preamp...
My last thought is there's probably a battery backup device that outputs a true sine wave for long enough to be useful for a listening session. Again, probably wont run the power amplifiers, but could be effective on more sensitive, upstream equipment. Looks like "PS Audio" has already made a purpose built device that provides 1500W of pure AC in the form of a BBU. Not cheap, even used https://www.ebay.com/itm/174508141538 but such a solution has been already commercialized for the audio market.
Looks like Westinghouse has a whole series of such devices, powered by lithium ion batteries, example https://www.homedepot.com/p/Westing...LED-Display-and-Flashlight-iGen600s/315510546
Have to believe the output of one of those would have less voltage artifacts than the dirty 'ol AC mains.
Use a battery charger, and run the Amp on DC.
Charge when not listening.
Solar may be suitable, even less noise.
No need for inverter, as most amps for normal use need no more than 48 V or 4 batteries in series.
Use one of the four for 12V for the pre amp and so on.
Charge when not listening.
Solar may be suitable, even less noise.
No need for inverter, as most amps for normal use need no more than 48 V or 4 batteries in series.
Use one of the four for 12V for the pre amp and so on.
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Technically good but complex solutions. Maybe not so good for private use when looking at todays energy prices. All consume extra energy to do their job. In that view I would prefer simple passive solutions. Electronic inverters are not the most clean devices either and for clean versions one will need to look at the audio brands and pay the mark up.
Constant voltage transformers often make too much mechanical noise. Not suitable for in home use.
The standard low leakage 1:1 isolation transformer (not mentioned yet I think) combined with internal mains filter is also a good device that filters without too much energy loss.
For a DIY passive AC mains filter, perhaps the Fo-Felix device seen in Group Buys here would be an effective option.
Some info can be seen here, at its initial announcement https://www.audiocircle.com/index.php?topic=156879.0
And also here, for the 1st Group Buy. https://www.diyaudio.com/community/...ilter-for-ac-mains-120-230v-by-folsom.321223/
There have been 9 Group Buys so far, the last earlier this year.
These filters are built around chokes selected for the expected load and desired filtration mode (common mode, or common plus differential). Chokes with ratings from 3A to 20A can be accomodated on the PCB. N.B.: the expected load should be no more than 25% of the choke rating, for a safety margin. Practically, this translates to one Fo-Felix per big amp, and one for several small signal devices.
The Group Buys are for the PCB and the Weco connectors for the mains. Other components and the enclosure are up to the builder to procure.
Some info can be seen here, at its initial announcement https://www.audiocircle.com/index.php?topic=156879.0
And also here, for the 1st Group Buy. https://www.diyaudio.com/community/...ilter-for-ac-mains-120-230v-by-folsom.321223/
There have been 9 Group Buys so far, the last earlier this year.
These filters are built around chokes selected for the expected load and desired filtration mode (common mode, or common plus differential). Chokes with ratings from 3A to 20A can be accomodated on the PCB. N.B.: the expected load should be no more than 25% of the choke rating, for a safety margin. Practically, this translates to one Fo-Felix per big amp, and one for several small signal devices.
The Group Buys are for the PCB and the Weco connectors for the mains. Other components and the enclosure are up to the builder to procure.
An excellent power conditioner for a stereo system would be a used 'Monster HTPS 7000 MkII' from ebay. That particular model is very good. It was designed by our own Richard Marsh and Demian Martin (aka 1audio). At some point Richard posted the schematics in one of the Blowtorch Preamp threads. I probably have them around somewhere if needed. Worth keeping an eye on ebay until a MkII turns up. Right now I only see the original version for sale there. https://www.ebay.com/sch/i.html?_fr...70.l1313&_nkw=monster+htps+7000+mkII&_sacat=0
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