After doing some research about EMI filters I saw that there isn´t much else from ready made ones. The most famous are Schafner, Corcom, Belling Lee, Epcos and so on.
Does any one have links or info on discrete DIY filters or commercial ones that are suited for High End audio?
And what would be suited for audio ? I would like some opinions on this subject.
Does any one have links or info on discrete DIY filters or commercial ones that are suited for High End audio?
And what would be suited for audio ? I would like some opinions on this subject.
Something like:
1uF cap across the mains.
Feed lines through a 12:12V transformer (be sure the phase is correct so it appears as turns on a core, not just plain wire 😉 )
Follow up with another 1uF.
Personally, I've noticed no difference.
Tim
1uF cap across the mains.
Feed lines through a 12:12V transformer (be sure the phase is correct so it appears as turns on a core, not just plain wire 😉 )
Follow up with another 1uF.
Personally, I've noticed no difference.
Tim
No, no! You must only use approved and safe parts! Mains filter is usually for EMI filtering and to get good results they must be compact with short connections.Sch3mat1c said:
I also recommend that you only use parts approved for X and Y applications. These caps are special and also safe.
Jon Risch's website -
http://www.geocities.com/jonrisch/surge.htm
Magnan Cables tweek page -
http://www.magnan.com/column.shtml#conditioners
http://www.geocities.com/jonrisch/surge.htm
Magnan Cables tweek page -
http://www.magnan.com/column.shtml#conditioners
I think the best solution is to copy a ready filter and use the correct X and Y caps of course.
What would the best configuration be though for audio that is?
Any general purpose filter will do but is not the best.
What would the best configuration be though for audio that is?
Any general purpose filter will do but is not the best.
I think you must ask yourself which frequencies you want to filter out. You can't really talk about "how it sounds". Normally filters for many amperes don't go so low in frequency because of the inductor size. The manufactures datasheets for component values. I suggest stronly that you buy a ready made filter becuase of the safety aspects. They aren't very expensive.
Get Rid Of That Damm AC Mains Noise...
I use a mains filter that I salvaged from a scrapped old main frame computer system (originally quite expensive I expect).
This thing is rated at 20 amps or so (from memory - it is at my workplace) and measures 2.5" high X4.5" wide X 6" long.
I have no idea of the circuit values off the top of my head, but I have found it to be sonically very beneficial for both home hi-fi use, and for every of many instances of 5000W PA usage.
Without a lot of trouble it would be perfectly possible to brew your own, but it is notable perhaps that the commecially available examples are in soldered shut hermetically sealed cans.
Eric.
I use a mains filter that I salvaged from a scrapped old main frame computer system (originally quite expensive I expect).
This thing is rated at 20 amps or so (from memory - it is at my workplace) and measures 2.5" high X4.5" wide X 6" long.
I have no idea of the circuit values off the top of my head, but I have found it to be sonically very beneficial for both home hi-fi use, and for every of many instances of 5000W PA usage.
Without a lot of trouble it would be perfectly possible to brew your own, but it is notable perhaps that the commecially available examples are in soldered shut hermetically sealed cans.
Eric.
I think a filter for audio should start from 1 KHz to cut.
What I dont know is if a filter should have two or one coils in series. What effects more the dynamics. I would be in favour of one coil.
What I dont know is if a filter should have two or one coils in series. What effects more the dynamics. I would be in favour of one coil.
Most mains filters are for filtering noise coming from the (switching) power supply and going out to the mains, not the other way around. Frequency range is 1-100 MHz. Filter under 1 MHz and a few amperes are quite big.
The LC filter is effective above 200 kHz and the filter is rather complex. If you want to reduce EMI you have to have instruments, you can't just listen.
My advice here is to use a ready filter and if you don't know how a filter should look like or which values, you shouldn't think at all about this, sorry but I means this. A bought filter is safe, is approved and you know what you get. If you have problems with transients (washing machines, fridges etc.) use a VDR (approved of course) across the mains lines.
The LC filter is effective above 200 kHz and the filter is rather complex. If you want to reduce EMI you have to have instruments, you can't just listen.
My advice here is to use a ready filter and if you don't know how a filter should look like or which values, you shouldn't think at all about this, sorry but I means this. A bought filter is safe, is approved and you know what you get. If you have problems with transients (washing machines, fridges etc.) use a VDR (approved of course) across the mains lines.
I was using a 10A filter with two coils in series for my cdp.
It improved things noticably.
Just recently I replaced it with an 80VA isolation transformer.
I tried combinations of the two, but just the isolation transformer without filter (before or after, big diff. btw) sounds best to my ears.
I will try some filter/motor run caps before and after later on.
It improved things noticably.
Just recently I replaced it with an 80VA isolation transformer.
I tried combinations of the two, but just the isolation transformer without filter (before or after, big diff. btw) sounds best to my ears.
I will try some filter/motor run caps before and after later on.
You should allways use a filter rated for your current, not use too large. 1 A filter has much better effect because the inductors can be made with larger inductance. DIY'rs do believe that "bigger is better" but in this case "smaller is better", if we talk current rating.rbroer said:
Isn't btw a CD a typical device which GENERATES much RF noise and therefore needs a lot of ferrite beads, rings, filter etc. to meet CE approval? CD's do normally have mains filters inside tuned for best effect in the MHz region.
Bricolo said:
Crazy really. Do you know how big the part would be? Better to analyze what's the real problem instead. Do you have something you want to filter out?
Mains Filter
Hi ,
Jon Risch was famous for his mains filter on Audio Asylum.
Do a search and you will find numerous posts.
http://www.audioasylum.com/audio/tweaks/bbs.html
Jon used rather large caps to ground and has been critised on that as his filter has the tendency to trip the Ground Fault Switch in the fuse box. Here in Holland this switch is obligatory in all new houses. Jon does find that a shame, but I am sure it saved lifes!
Hi ,
Jon Risch was famous for his mains filter on Audio Asylum.
Do a search and you will find numerous posts.
http://www.audioasylum.com/audio/tweaks/bbs.html
Jon used rather large caps to ground and has been critised on that as his filter has the tendency to trip the Ground Fault Switch in the fuse box. Here in Holland this switch is obligatory in all new houses. Jon does find that a shame, but I am sure it saved lifes!
How many mH or H do you need?Bricolo said:
How must the inductor be designed so it really blocks high frequencies?
How big caps do you need?
How low impedance is required at 50 Hz?
How high impedance is needed outside the 50 Hz band?
Something to think about.
50 Hz is too low to filter. the parts needs to be giant, thats the reason most good filters start from 1-2 KHz. And these are big.
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