Emi Filter Plus Elite & DC blocker schematics and motherboard
I had built my own version of a very advanced EMI filter which is still available from here https://775mv.com/product/power-emi-filter-for-audio-12a/ for being purchased at a good price, but I like building things, and modify them according to my needs. First I did not need to filter my entire house using a single high amps filter, because it may be more efficient to use several low current filters instead of one. Therefore I could choose higher inductances with higher attenuation of the noises which circulate on the 220Vac power supplies. I am using a DIY audio Dolby Atmos 16 channel amplifier power, having 8 distinct stereo modules, each with its own power supply, torroidal transformers and rectifiers.
Situation before adding EMI filters:
a) trafo noises and hum because of the DC offset which exists on the network, and obviously I didn't used any DC blocker circuit before.
b) regular EMI filters are just not good enough and they don't filter below 100 kHz, and I needed something to filter below 10 kHz
c) all power transistors from each module where just unusual overheating, without pushing too much the volume ... because all these noises were just passing through into the DC components, almost unfiltered by the electrolitic capacitors.
d) audio distorsions were very intense after pushing some power into the loudspeakers and transistors continued overheating very much
e) ground noises even after changing all audio cables with high expensive professional ones.
f) big noise in the loudspeakers after switching to power on, a big sharp and short boom.
Situation after adding individual EMI filters to each module:
a) no more trafo noises and hum, DC blockers have been added too.
b) filtering all noises and foreign signals above 10 kHz, present in the 220Vac wires from the surge protection unit of my home.
c) transistors are no longer overheating, sound quality improved because of using them in normal range, and the entire sound quality improved.
d) very soft noise in the loudspeakers after switching to power on, low intensity short boom.
The schematics contains: a) DC blocker, b) Advanced ground loop breaking, c) Deep suppression of differential noise stage I (F1,F2,C1,C2,C3,C4,C10), d) Zero noise overvoltage protect (RV1,RV2,RV3) and also Gas Discharge Tube technology GDT, e) Deep suppression of common mode stage using Tr1 and Tr 2, followed by suppression of differential noise stage II and III, (L1,L2,L3) and f) Careful dempening of complex filtering (C8 and C9)
I had built my own version of a very advanced EMI filter which is still available from here https://775mv.com/product/power-emi-filter-for-audio-12a/ for being purchased at a good price, but I like building things, and modify them according to my needs. First I did not need to filter my entire house using a single high amps filter, because it may be more efficient to use several low current filters instead of one. Therefore I could choose higher inductances with higher attenuation of the noises which circulate on the 220Vac power supplies. I am using a DIY audio Dolby Atmos 16 channel amplifier power, having 8 distinct stereo modules, each with its own power supply, torroidal transformers and rectifiers.
Situation before adding EMI filters:
a) trafo noises and hum because of the DC offset which exists on the network, and obviously I didn't used any DC blocker circuit before.
b) regular EMI filters are just not good enough and they don't filter below 100 kHz, and I needed something to filter below 10 kHz
c) all power transistors from each module where just unusual overheating, without pushing too much the volume ... because all these noises were just passing through into the DC components, almost unfiltered by the electrolitic capacitors.
d) audio distorsions were very intense after pushing some power into the loudspeakers and transistors continued overheating very much
e) ground noises even after changing all audio cables with high expensive professional ones.
f) big noise in the loudspeakers after switching to power on, a big sharp and short boom.
Situation after adding individual EMI filters to each module:
a) no more trafo noises and hum, DC blockers have been added too.
b) filtering all noises and foreign signals above 10 kHz, present in the 220Vac wires from the surge protection unit of my home.
c) transistors are no longer overheating, sound quality improved because of using them in normal range, and the entire sound quality improved.
d) very soft noise in the loudspeakers after switching to power on, low intensity short boom.
The schematics contains: a) DC blocker, b) Advanced ground loop breaking, c) Deep suppression of differential noise stage I (F1,F2,C1,C2,C3,C4,C10), d) Zero noise overvoltage protect (RV1,RV2,RV3) and also Gas Discharge Tube technology GDT, e) Deep suppression of common mode stage using Tr1 and Tr 2, followed by suppression of differential noise stage II and III, (L1,L2,L3) and f) Careful dempening of complex filtering (C8 and C9)
Attachments
Unfortunately no, but I was taking as valid those made by the original creator of the schematics, a guy named Patrushin who now has these wonders for selling as DIY kits or assembled, and there are a lot of graphs and measurements, see link in the presentation.
I am sorry to see that the entire website of https://775mv.com/product/power-emi-filter-for-audio-12a/ is totally down and deleted... only some cache files are still visible but without actually see the content...
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Here is some good news ... the video of Patrushin testing the device is still valid here
site is back ... https://775mv.com/?fbclid=IwAR1xHCXQtC_52GxzZ3DYtRYn7pmt8alvTGclGP9hXGsi6C_eyoCPesNUAnQ it seems that was a temporary problem
You can copy exactly my drawing and is the same thing. My schematics is a little improved ... you have the motherboard in the photos
I understand, but I have no software to make the conversion to something that can be sent to a PCB maker.
Regards, Gerrit
Regards, Gerrit
In my city there is a private manager which can create the PCB directly from a jpg photo ,,.. I am sorry I can't help you... buy the filter directly from that website...
Hello! 775mv.com website admin here 🙂
Apologies for the periodic website down times, my dad (who's the electronic wiz and the mastermind behind every filter on there) built it on wordpress for ease of use, which proved more and more problematic with time.
I'm aware of the issues and working on rebuilding it from the ground up (big improvements coming up). 😉
Apologies for the periodic website down times, my dad (who's the electronic wiz and the mastermind behind every filter on there) built it on wordpress for ease of use, which proved more and more problematic with time.
I'm aware of the issues and working on rebuilding it from the ground up (big improvements coming up). 😉
Inductors and chokes with higher current capacity are available but I don't have idea how the changed specs reflect on the the filter, especially its stability and filteration capabilities.
Hi @Moor thank you for sharing the schematic of the modified EMI filter. Even though I am replying to an older discussion, I recently reviewed the schematic and noticed a detail that raises some questions.
RV1 and RV2 are connected to the GDT instead of directly to GND. This means that RV1 and RV2 cannot function properly, as the connection to GND remains open until the GDT activates at 500V. This is likely not the intended behavior.
Additionally, R2/R8 and C3/C10 appear to have no function without a proper connection to GND.
I may be misunderstanding something, so I would appreciate your feedback on this observation or maybe some one else can give me his ideas
Looking forward to your thoughts.
Kind regards
RV1 and RV2 are connected to the GDT instead of directly to GND. This means that RV1 and RV2 cannot function properly, as the connection to GND remains open until the GDT activates at 500V. This is likely not the intended behavior.
Additionally, R2/R8 and C3/C10 appear to have no function without a proper connection to GND.
I may be misunderstanding something, so I would appreciate your feedback on this observation or maybe some one else can give me his ideas
Looking forward to your thoughts.
Kind regards
Hi, Korniman
You are correct, RV1 and RV2 should be connected to the Ground and the other terminals of the GDT should go directly to Phase and Nul. However, I am already using this circuit for years and nothing bad had happened. I just copied another schematic and there I saw the connection, so I duplicated without asking myself if it 100% correct. Actually only if the voltages is increasing toward very high values (which extend the RV1,2,3 maximum range) only then the GDT start to do its job. The designer thought that for lower spikes (up to 300Vac) the RV1,2,3 would be sufficient, but then he thought to add an extra-protection using GDT in order to extinguish the flame of a much higher voltage spike. That depends where your home is connected to, and how good or bad is that AC network. But in the end, electronically speaking, I agree with you and you may modify the schematic.
You are correct, RV1 and RV2 should be connected to the Ground and the other terminals of the GDT should go directly to Phase and Nul. However, I am already using this circuit for years and nothing bad had happened. I just copied another schematic and there I saw the connection, so I duplicated without asking myself if it 100% correct. Actually only if the voltages is increasing toward very high values (which extend the RV1,2,3 maximum range) only then the GDT start to do its job. The designer thought that for lower spikes (up to 300Vac) the RV1,2,3 would be sufficient, but then he thought to add an extra-protection using GDT in order to extinguish the flame of a much higher voltage spike. That depends where your home is connected to, and how good or bad is that AC network. But in the end, electronically speaking, I agree with you and you may modify the schematic.
Hallo @Moor, Perfect, thank you for the very rapid answer. Yes, I also agree from schematic check that the schematic will work under normal conditions. Maybe with R and C direct connected to GND (not over GDT results are maybe bit better as you get an additional filter). Before I also will rebuild the filter, can you maybe tell the function for the Transistor/LED/Z-Diode circuit. It seems one LED (D3) is a AC Power Indicator. Can you agree? But what is the part with the Transistor/LED (D4)? Under which condition will the LED work?
As I told you, I only reversed engineering a secret schematic, based upon some front and back side board photos and deducted how they were connected, ... that transistor and the LED's are for detecting the Null and Phase in regard with the Ground which obviously needs to be an earth deeply grounded copper wire, or else it won't work. If RED is light then everything is OK, but it is not necessary to really add this circuit to every module filters. I have 10 built until now.