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

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maty

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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 !!!