How to clean the DC at mains. And ripple too.

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maty

Re: How to clean the DC at mains. And ripple too.
« Reply #120 on: 21 Dec 2018, 05:35 pm »
After reading a private email (from other forum), I think it is convenient to leave in writing:

I do not sell any audio device and I do not receive any commission from any vendor.

If someone knows of a better or equivalent product, I would ask you to comment on the thread, because I am the first interested in the search for excellence, in audio or in any other field.

Every time I find it harder to participate in the open Internet :(

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #121 on: 2 Jan 2019, 04:03 pm »
Informative reading about SMPS noise or 'conducted ripple'.

SMPS for Hi-Fi?

by Eva #4

https://www.diyaudio.com/forums/power-supplies/45589-smps-hi-fi-post510829.html

Quote
'Noise' is a classic misconception about SMPS

Speaking properly, there is no noise in SMPS, since noise by definition is a signal of random nature and what SMPS produce on their output is periodic 'ripple' as any 50/60Hz supply. We could call this 'conducted ripple'

This ripple is usually a sawtooth waveform and it may have some RF ringing on transients [on the peak and valley of the sawtooth cycle]. There's not much difference from 50/60Hz supplies, except the ripple frequency is about 1000 times higher.

As in 50/60Hz supplies, ripple is easily filtered with pi filters and it may be attenuated as desired [even below noise floor], but with the advantage of size since 100Khz pi filters are much smaller and cheaper than 100Hz pi filters...

Note: Eva designs class D amplifiers to professional audio.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #122 on: 17 Feb 2019, 06:18 pm »
I think what I just wrote in other forums (The diyAudio First Watt M2x) is relevant in this thread as well. There for the Mumetal and here for the toroidal transformers.

Audio Transformers by Bill Whitlock

[PDF] http://www.jensen-transformers.com/wp-content/uploads/2014/09/Audio-Transformers-Chapter.pdf

Page 9

Quote
The effectiveness of magnetic shielding is generally rated in dB. The transformer is placed in an external magnetic field of known strength, generally at 60 Hz. Its output without and with the shield is then compared. For example, a housing of 1/8" thick cast-iron reduces pickup by about 12 dB and a Mumetal can by about 30 dB. Where low-level transformers operate near strong magnetic fields, several progressively smaller shield cans can be nested around the transformer. Two or three Mumetal cans can provide 60 dB and 90 dB of shielding respectively. In very strong fields, because high-permeability materials might saturate, an iron or steel outer can is sometimes used.
   
Toroidal power transformers can have a weaker radiated magnetic field than other types. Using them can be an advantage if audio transformers must be located near them. However, a toroidal transformer must be otherwise well designed to produce a low external field. For example, every winding must completely cover the full periphery of the core. The attachment points of the transformer lead wires are frequently a problem in this regard. To gain size and cost advantages, most commercial power transformers of any kind are designed to operate on the verge of magnetic saturation of the core. When saturation occurs in any transformer, magnetic field essentially squirts out of the core. Power transformers designed to operate at low flux density will prevent this. Often a standard commercial transformer, when operated at reduced primary voltage, will have a very low external field.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #123 on: 29 Jun 2019, 08:03 am »
I agree with Danny Richie at 100%.  It is a process of trial and error until you find the maximum attenuation without the dynamics of the music being affected.

https://www.audiocircle.com/index.php?topic=164405.msg1748970#msg1748970

Again, your amps were effected by those changes here as well.

We have also found that A/C power conditioning and filtering to be pretty tricky. Too much can cause as much of an issue as not enough. I've tried power cables with a high level of filtering of RFI and EMI plugged straight into the wall on a piece of gear and got fairly good results. But plugged into the balanced power supply it was too much and sucked the upper detail, spacial ques, and life right out of the music. But a power cable with much less filtering characteristics worked great with the balanced power supply...

It is cheaper to use RF/EMI Schaffner inlet filters and Würth 150 kHz ferrites and other tricks.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #124 on: 17 Jul 2019, 02:33 pm »
Aleksandar has a new product: DC Blocker/Trap/Filter + Common Mode Filter:

PCB for Combined DC Blocker (trap) & EMI/RFI filter

https://www.atlhifi.com/shop/bare-pcb/pcb-for-dc-trap-blocker-and-emi-rfi-cm-filter/


Scheme




For now, only the PCB.




Assembled PCB, as an example




Quote
...The unit proposed here is comprised by two sections – a DC Blocker/Trap/Filter and a Common Mode Filter (CMF).

The DC trap section will remove or at least lower the toroidal transformer buzzing. Schematic is similar to this one used in well known Vladimir Shushurin’s Lamm-1 amplifier. An article with in-dept explanation of how DC blockers work can be found on Rod Elliot’s site ( http://sound.whsites.net/articles/xfmr-dc.htm ).

The Common Mode Filter will deal with the high frequency pollution in the AC Mains Network. It was inspired by the very successful Felix project ( https://www.audiocircle.com/index.php?topic=25757.0 )

maty


WireNut

Re: How to clean the DC at mains. And ripple too.
« Reply #126 on: 17 Jul 2019, 03:03 pm »
Hi Maty,

I like that PCB. Nice to have everything on one board.
I'll have to get a couple.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #127 on: 17 Jul 2019, 03:25 pm »
FO-Felix in the house by MttBsh

https://www.audiocircle.com/index.php?PHPSESSID=adc7vbp9cbqehppjmfba10l3o5&topic=161544.0

Quote
...Once installed, it took a few days for me to really begin to hear improvements, but now, a week in, those improvements have gone from subtle to transformative. The best word I can think of to describe the sound I'm getting now is "effortless". Any trace of stridency, boominess or glare that was present is gone. The sound is more clear, wide open and "fuller", with uncanny 3D depth and the deepest bass I've ever heard, low level details are floating in the air. These are exactly the kinds of improvements I had hoped good power conditioning could provide, but it's much more than I expected...

One of the main bottlenecks of our audio systems is the quality of the electricity supply that we suffer. In the real world we have to live with the imperfections but we can try to minimize them, spending as little as possible for it, using technical / professional solutions.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #128 on: 17 Jul 2019, 03:53 pm »
Well, the assembled and tested version already exists:

Combined module DC Blocker (trap, filter) & EMI/RFI/Common Mode Filter – assembled and tested PCB

https://www.atlhifi.com/shop/populated-pcb/combined-module-dc-blocker-trap-filter-and-emi-rfi-cm-filter-assembled-and-tested-pcb/



Quote
...The unit has following abilities:

DC Blocker Section

It is calculated to handle max. current of up to 16A
– On the board are mounted 6 discrete high-power diodes 10A4 which yield the max. DC Blocking voltage of approx. 2 Vdc.
two MASSIVE 47,000 uF EPCOS capacitors (the bigger is capacitance, the higher are handled currents).
– one 10W power resistor.
– one bypass WIMA MKS4 400VAC capacitor.


Common Mode Filter Section

It is calculated to have a corner frequency of approx. 20 kHz and max. handled current of 20A with the parts used
– 4 pcs. X2 type safety polypropylene capacitors
– 2 pcs. Y2 type safety polypropylene capacitors
– Triad Magnetics Common Mode Choke, rated at 20A
– AC input/output connectors can be of the following types:
– 3-pins terminal blocks with lead spacing 5 mm.

NOTE: Some parts of the unit (DC Blocker’s electrolytic capacitors and diodes, Common Mode Choke, X2/Y2 capacitors, Input/Output terminals) can be replaced with another ones upon customer’s request, as it’s shown on the pictures.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #129 on: 18 Jul 2019, 04:58 pm »
Today we have the graphs.


In-depth explanation and examples of Common Mode Filters can be found here:

[PDF] https://www.schaffner.com.tw/fileadmin/media/downloads/application_note/Schaffner_AN_RB_common_chockes.pdf


In the process of CMF simulation the following results were outlined:

The damping resistors lower the spike in frequency response with approx. 20 dB



CMF without damping resistors




CMF with damping resistors


Removing the load-side shunt capacitors (as supposed in the Fo-Felix version of the filter) will give us a smoother frequency response but the corner frequency is shifted to the higher frequencies approx. 25 times



CMF without load-side shunt capacitor


rollo

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Re: How to clean the DC at mains. And ripple too.
« Reply #130 on: 18 Jul 2019, 05:07 pm »
  Good work. Thank you for the effort and time spent as well for the graphs. I would be curious to see same graphs for a PC that one can buy. Furman, PS audio Shunyata, etc. Is the DIY version better, worse, close enough for the money.
  Maybe another thread.


charles

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #131 on: 18 Jul 2019, 05:35 pm »
The problem of the dirt present in mains does not stop to increase because of the new gadgets. The last and inevitable are LED lights and dimmers. Unfortunately many of those lights and dimmers from Asia and cheap breach the regulations on EMC before the passivity of the authorities, as is already the case with cheap SMPS chargers.

[PDF] https://www.schaffner.com.tw/fileadmin/media/downloads/application_note/Schaffner_AN_RB_common_chockes.pdf

page 4



I was unaware that the new problem starting at 9 kHz !!!

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #132 on: 27 Oct 2019, 09:49 am »
Aleksandar already sells RF/EMI common mode filters+ DC Blocker assembled inside a box.

https://www.atlhifi.com/shop/fully-assembled-devices/combined-module-dc-blocker-emi-rfi-common-mode-filter-assembled-in-case/  € 100 + shipping

Quote
Common Mode Filter Section

It is calculated to have a corner frequency of approx. 20 kHz and max. handled current of 20A with the parts used

– 4 pcs. X2 type safety polypropylene capacitors
– 2 pcs. Y2 type safety polypropylene capacitors
– Triad Magnetics Common Mode Choke, rated at 20A


The PCB is mounted in a steel enclosure with following characteristics:

– Schurter IEC power inlet with fuse
– Schneider AC Power outlet (Schuko, French, Euro-American, United Kingdom or Italian).
– steel case black powder coated
– 4 small rubber feet underneath the case.

Dimensions of Combined module DC Blocker & EMI/RFI/CMF: 125x165x75 mm. (WxDxH).
Weight: ~ 1.25 kg.








I have not tried them but the attenuation graph is spectacular. If I ordered one for me it would be with the expensive but very good BIG Mundorf Mlytics in the DC Blocker. My problem is that I do not need a new DC Blocker, at least try the RF/EMI common mode filter if I finally buy or build a new amplifier (maybe with new PURIFI 1ET400A kit modules with switched PSU and RME ADI-2 DAC like a preamp too) to my second audio system.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #133 on: 17 Nov 2019, 11:44 am »
Now, the DC Blocker v3

https://www.atlhifi.com/shop/fully-assembled-devices/dc-blocker-trap-filter-assembled-in-case/

Quote
It retains most of the previous unit’s abilities but for the first time now the customer can chose a board with 6 discrete diodes which increases the ability for DC blocking up to 2 Vdc.

DC Blocker is built with following parts:

– MASSIVE 47 000 uF EPCOS capacitors (upgrade over the older 33000uF)
– Six high-voltage diodes 10A4 (2V DC Blocking voltage) or one bridge rectifier (1.4V DC Blocking voltage)
– 10W power resistor
– WIMA MKS4 400VAC capacitor
– MOLEX 3-terminal connectors for AC input/output
– Schurter IEC power inlet with fuse
– Schneider AC Power outlet (Schuko, French, Euro-American, United Kingdom) or IEC C14 outlets
– steel case black powder coated
– 4 small rubber feet underneath the case.

Optimized picture


maty

Re: How to clean the DC at mains. And ripple too.
« Reply #134 on: 29 Dec 2019, 08:42 am »
https://www.audiosciencereview.com/forum/index.php?threads/when-to-use-how-to-choose-a-power-conditioner.9629/page-3#post-291419

by trl



Mains AC - 230V measured with an 230-115V converter (a coil/inductor placed in series)




Same as above, but with a low-quality (probably defective) SMPS in the same outlet (notice the THD increase due to the DC added on top)




Noise measured between Null and Earth when vacuum runs (it is pretty close to zero without vacuum cleaner)


Most of the time I prefer to use an isolation transformer (a cheap one) to my audio stuff (not to my speakers amp) because there's some filtering that is done by the transformer, also the removal of the DC coming from the bad switching supplies (if exists nearby). Also, if a poor SMPS gets inserted into the outlet from the outputs of the transformer, then there's going to be a strange noise coming from transformer's coils, so it's easy to troubleshoot which SMPS is not OK and which one is not.

- End of quote -

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #135 on: 3 Jan 2020, 11:24 am »
As I have already written about RF / EMI in this thread, I take the opportunity to add a very interesting new link. Only 30 graphs!!!

Sensitivity of opamps to air coupled EM fields, especially of the LM4562/LME497X0 family by PMA

Quote
This has been (and will be) a long story that started back in the year 2008 when I started with intensive testing of various opamps concerning their susceptibility to electromagnetic fields in the air or from the inside of the instruments. Quite a long row of opamps was tested, including uA741, uA1458, LM358, OP97, TL071, TL072, AD829, AD844, AD797, AD825, LT1028, LT1122, OPA134, OPA2134, OPA627, OPA211, OPA827, LM6171, LM4562, LME49710, LME49720, NE5532. So they were both BJT and JFET input stage opamps, slow and fast, low supply current or standard supply current. Some of them performed very well and were almost unaffected by a “normal” lab or home environment EM field that surrounded the test PCB or box, some were performing “moderately” and some were performing very poorly, reacting to a slightest change of EM field in their vicinity, like changing their position on a test bench or approaching a hand or just a move of the air or of the body at a 1m distance.

In general, JFET input opamps have had no problems and the behavior of BJT input opamps was very different, from excellent immunity to horrible sensitivity to a slightest change in their vicinity. As a conclusion, absolutely worst behavior was that of the LM4562/LME49710/LME49720 family, bought several times in the past 12 years, directly from the manufacturers or authorized distributors.

No fakes, no cheap buys. Every time I published some of the results, it started strong reactions and dissatisfaction, especially of the people involved in audio production who have been using those parts that did not perform well...

* 1st round, March 2008

* 2nd round of measurements

* 3rd round of measurements, January 2016

* Battery power

* 4th round of measurements, January 2020



Fig.30. Noise gain 86dB test, LM4562 output for 100Hz input.


Conclusion

Quote
As a conclusion, there was never a problem with JFET input opamps, there was never a problem with bipolar input opamps AD797, LT1028, AD844, there were slight issues with LM6171 and NE5532 and there were big issues, always, with the LM4562/LME497X0 family. This family of opamps is extremely sensitive to EM fields in their vicinity, mains frequency 50Hz triggers them during zero crossing and they send narrow spikes to their output, in 100ms distances and of amplitude that depends on shielding.

This can be cured extremely well shielded box that shields not only against electric field component, but also against magnetic field component. The problem may remain hidden, sometimes it disappears with respect to momentary EM field conditions, but can be seen also for gains as low as -1 in the professional TI LME49720NABD evaluation board. The problem was observed by various soundcards and PCs in 2 independent measuring places and also by using analog and DSO scopes. It looks like a duck, it quack like a duck, so it would be a duck.

maty

Re: How to clean the DC at mains. And ripple too.
« Reply #136 on: 3 Jan 2020, 11:30 am »
Why did I select precisely that graphic? Because LM4562 is the opamp used in the very expensive Hypex NC1200 class D amplifier.

https://www.audiosciencereview.com/forum/index.php?threads/hypex-nc1200-quality-of-the-implementations.7918/

I just want to remember that since I participated in the threads on the new IcePower 1200AS2 I insisted again and again on the importance of having a suitable box to avoid RF / EMI.

Then about the cables and starquad geometry.

Before, RF / EMI filters and 150 kHz ferrites too.