[Hap]

The Magnan Audio website has a DIY article: "DIY approach to AC line filtering"
http://magnan.com/doityourself.html

While their suggestions do not include the use of a CMC, they do recommend the use of a lot of capacitors in the AC circuit which they claim has an almost unbelievable effect in improving the sound of digital.
They also state there are no commercially available units equivalent to the designs they are suggesting.

I do not have much knowledge in this area, so thought I'd like throw this concept out for comment.

Magnan states the more capacitance on the more AC receptacles and separate AC lines the better.  We have not yet found a point of diminishing sonic returns in increasing total capacitance...they also suggest AC line to neutral filters using four 10uf bypassed with .47uf and .01uf, which your digital source would plug into.

I asked Occam about these Magnan filters a while back and he suggested novices like myself avoid building these types of filters and try building a Felix first, which has yielded great results thus far; 14 and counting.

Cheers

 

[Folsom]

Interesting... I do not think I could afford to build one with that much capacitance since Solen is the cheapest in that range. However the neutral to earth ground I might have to look into!

[kyrill]

very interesting
But if you want to go so far, why not start for the audio system a balanced transformer? Even two in series with a felix in between for the source components. I have read this suggestion before

[Folsom]

You mean like an isolating transformer? Things like that cost $600+ is my reason.

[Daryl]

Daryl,

If you goal is to test where my moderation boundaries are, you are doing well.  Debates, discussions, even heated are acceptible, but personal attacks aren't. You post is clearly trying to insult and insight.  You've been warned.

Now your talking Josh,

I must say when Smile Destroyer PM'ed me with a thanks and a link to this thread I was a little taken back.

I thought since when is this acceptable.

Even if someone was right about what they were saying it wouldn't be alright but this IMO was particularly disgraceful and I couldn't resist the urge to cut and paste some of the insults and turn them around.

My appollogies.

[Daryl]

You don't use the minimum load impedance differential leakage inductance and filter capacitance with a rigid voltage source to model the circuit (it doesn't work that way).

Well then, explain to us how it does work.

That explaination was contained in that same post where I explained how the impedance of the source also effects Q.

Here is a diagram...


First load impedance is not what it's cracked up to be.

That is if your thinking it's going to be resistive.

Even if it was (few types of loads are) it likely would not be up near the corner frequencies of these filters where it will influence Q.

Most all loads are transformers driving rectifiers feeding supply filter capacitors.

Most of the time the load is high impedance due to the supply filter capacitors reverse biasing the rectifiers.

It's only at the peaks of each half-cycle that the rectifiers become forward biased and the transformer see's a low impedance.

Most of the time you have just the inductance of the transformer for a load.

Also up near the corner frequencies of these filters the leakage inductance of the transformers is going to add to the load impedance increasing it still.

The worst case scenario is that the load impedance is infinite (no load).

Due to the reality of how real world loads present themselves (what I just pointed out above), no load is how these filters should be analyzed.

At first you might think that no load would result in extremely high Q's for the filters but theres more to it.

I am speaking of the impedance of the noise source that you intend to filter.

Source impedance affects filter Q also but in the opposite way compared to load impedance (as source impedance increases Q goes down where Q goes up as load impedance increases).

The AC power on the line does have a low source impedance and the distribution network (power lines) at 60hz doesn't add much to it's impedance.

Noise sources however such as generated on a motors brush's or in a light dimmer aren't such perfect sources and will have considerable source impedance.

Also at higher frequencies the distribution network will add more impedance to the total.

I have entered the values for both circuits into LEAP for analysis.

The worst case of no load is being used here with varying values for source impedance (1, 3, 10, 30 and 100ohm).

The impedance of noise sources of course will vary depending upon what generates them how far away on the distribution network they are located and frequency (in general higher frequencies will have higher impedances).

Hear are the charts...



You can see you are unlikely to get much attenuation below 50khz with the Felix but with the Snazzy design you can see decent attenuation starting with 1600hz.

[Folsom]

Oooo I am excited! I know some people do not like all of Daryl's information but I do.

I am going to try a neutral to ground filter with a Solen (100uf) capacitors and two of the GE's, so 110ufish area. I figured throwing in the GE's would lower impedance a little. My choice in capacitors goes along with that other website and space constraints. I suppose later I could if room permits throw in another Solen and two more GE's.

[Hap]

My experience with the neutral to ground caps is that you will more than 6 of these plugged into as many separate AC circuits throughout the house.
I first took the lazy approach and plugged all of them into one strip, which subsequently produced little gains.
So then I spread these all over the apartment and while it did not have an "unbelievable effect in improving the sound of digital" like Magnan states, they did make the noise background quieter.
Cheers

[JoshK]

Daryl,

I am assuming LEAP is some sort of simulation software.  Can you provide the values use to set up the graphs?  The assumptions, etc.  Are you modeling the differential inductance as well?

Can you provide reference to why you chose the noise source impedance that you did? 

I am also confused by the attenuation at 60hz.  In the snazzy graphs it shows considerable attenuation at 60hz for higher source impedances.   I can't imagine this is a positive attribute.

[Folsom]

I am also confused by the attenuation at 60hz.  In the snazzy graphs it shows considerable attenuation at 60hz for higher source impedances.   I can't imagine this is a positive attribute.

I think where it would attenuate at or below 60hz at specific impedence, the issue is almost 100% moot based on this factor

(total)=SQRT(Ir^2+Ic^2).

Where:
SQRT()=Square Root.
Ir=Resistive load current.
Ic=Capacitor current.

As the resistive load current gets higher the additional current due to the capacitors gets smaller and smaller.

For inductive loads the total current is actually less than the load current...

I(total)=Ic-Il

Where:
Ic=Capacitor current.
Il=Inductive load current.

I guess what I am not sure of is what makes 60hz the inherent signal, even if shunting does not work on it, but it works on other frequencies. Do capacitors takes the dominate signal to operate out of the frequency at 90 degrees different phase of 60hz? Then again you have amperage and voltage no matter what, so frequency is not as important so long as you are converting to DC, but what if you are not? I do have an mmf-5 and the motor is a lot more audiable than I would like through the needle. I have no idea if it is DC or AC though. It is however playing at the right speed if it is AC and for some reason line was not 60hz.

[kyrill]

i am a bit confused now,
first i thought that "snazy"was a "poor" filter: 
"the ridiculous amount of capacitance, and your anticipated minimum load. The Q should be <1. Yours isn't. You are amplifying noise at the pole frequency, not attenuating it."

but looking at the latest graphs from Daryl to my non EE eyes the Snazy looks very much better than the official Felix?

[JoshK]

Kyrill, et al,

I don't think we should jump to any such conclusions just yet.  After all, Daryl has shown simulations, not measurements (ala a real world circuit on a bridge analyzer).  This goes a bit beyond my understanding and I won't pontificate which should sound better, but at this point I still consider this to be an unproven concept.

If some unbiased parties were to build both filters and report back we would have some empirical evidence.  Or if someone with access to measurement equipment was to measure both under real world conditions then we would have that data to explore.

To me simulations are a lot like mathematical models, they are only as good as the assumptions they are built on.  I have asked Daryl to report back with some clarification on his assumptions and more explaination of his model. 

I am keeping an open mind.  However, the fact that DOS's filter draws 5 amps makes me nervous.  Having relative newbies build unproven mains filters makes me doubly nervous**. 

Without a cap in front of the CMC, you aren't going to get filtering of what the component is putting back onto the line (differentially).  What happens to the power factor?  I have some more questions, that might be clear to others, but not to me.

** no offense to DOS, but his admitted errs, which we all make when we start out, leads me to believe he is still early on in his DIY journeys.  Playing with large mains (unproven no less) filters isn't a newbie project IMO.  Just like a tube newbie shouldn't be building 845 SET amps with 1000+ B+ voltages.

The Felix topology looks like a million other power filters out there both industrial and audiophile.  I've never seen any commercial filter, such as Corcom, et al, that looked like this topology.  It doesn't mean it isn't any good but to me it begs the proof and data to support its efficacy as well as safety. 

[Folsom]

Well by the same regards the Felix is completely unproven just as much. There has been nothing but subjective measurements of sound quality and then unemperical data plots.

I would be happy to build a Felix and try it on my Squeezebox to compare, if someone gave me the parts. I am not biased, I just went the route that had the most information that I could conclude (look up) to my accurate and understand. I found dead ends with the Felix and just a bunch of "go do this" to find nothing usually.

Josh in reality the draw of mine, unloaded, is only interesting in point as a regular Felix if it had one 5uf capacitors in it. They are all 400v capacitors, no issue with voltage... What is the difference between the draw on the lines or some on the capacitors? The concern would be if the capacitors got hot, which they do not even get warm in my cold house, or something that would lead you to believe they pose some kind of danger. I think the point should be made that AC line voltage and amperage capability is what is dangerous no matter what you are doing whether it be a filter or a tube amp, if you got line voltage you better be very careful.

I am new to DIY in the terms of I have not been doing it for 10 years (started getting into electronics in 2000 but no interest in professional direct so I did not continue it in school). I am not new to line voltages. I am new to lead free soldering though!

If it makes you feel any better I had an electrician drill out all my holes, and did end up overseeing everything anyway. He has experience with large voltage and amperage probably no one on this board has (plants for cutting titanium that can drain a city of power).