My power supply project-filters questions.

Lestraveled

Joined May 19, 2014
1,946
There are fools and then there are fanatics. I think Ian is talking about fools. The fanatics I am talking about claim that they can hear the difference between an amplifier that has electrolytic capacitors in the signal path verses an amplifier with film capacitors in the signal path. Of course, there are differences in ESR and inductance that can effect the response of an amplifier with film verses electrolytic, but to say that there is a "sound" associated with either capacitor, is a bit too much.
Blind tests do not support that film caps are better than electrolytics, but a fanatic doesn't care. He hears what he hears. If film caps makes you happy, more power to you.
 

ian field

Joined Oct 27, 2012
6,539
There are fools and then there are fanatics. I think Ian is talking about fools. The fanatics I am talking about claim that they can hear the difference between an amplifier that has electrolytic capacitors in the signal path verses an amplifier with film capacitors in the signal path. Of course, there are differences in ESR and inductance that can effect the response of an amplifier with film verses electrolytic, but to say that there is a "sound" associated with either capacitor, is a bit too much.
Blind tests do not support that film caps are better than electrolytics, but a fanatic doesn't care. He hears what he hears. If film caps makes you happy, more power to you.
Apparently some guitarists can tell by the sound whether a fuzz pedal has germanium or silicon transistors.
 

Lestraveled

Joined May 19, 2014
1,946
The "flavors of op-amps" is exactly what I am talking about. (Good example Ron) Precision op-amps are not "sweet", or "warm", or "dark". They are precise far beyond the human ears ability to tell the difference. But, again, they hear what they hear.
 

#12

Joined Nov 30, 2010
18,223
I am an audiophile. I work for audiophools. If they want Orange Drops in their Super Reverb and green Chicklets in their TS-9 Tube Screamer, that's what they get. There is no point in arguing. If this person wants to install an ineffective row of parts that allegedly filter, let him. The best hammer he has is an online filter calculator. That's what he is going to hit the problem with. It doesn't matter that he does not understand the resistance of the wire in the transformer secondary, the inductance in circuit board tracks, the limitation of the human auditory system, or the fact that you can't get 10KHz out of a wall outlet. Gigahertz must be filtered!

Answer the question or you will never cash another check from this customer.
 

wayneh

Joined Sep 9, 2010
17,153
I was looking up something about capacitors and came across a "serious" discussion reviewing the intricate audio characteristics of various BRANDS of electrolytic capacitor, and even between the various lines from those manufacturers. Ah, here's one.

I thought it was an April Fool's prank, but apparently not. Precise looking charts of "tone realism", "voice definition", "space clarity" and more. Sonic restitution!
 

Lestraveled

Joined May 19, 2014
1,946
I wouldn't be surprised to see a paper on, "The intricate audio characteristics of various BRANDS of electrolytic capacitors", with orange borders, coming to a site near you.
 

Thread Starter

prashanthb

Joined May 17, 2015
34
@ronv : Thanks a lot for the simulation you have done. Such help really helps!
If double regulator handles the 100Hz ripple well then I will accord it a higher priority than the filter(present specifications) then.

My concerns about the LM317 idea :
Voltage drop : I need 30~35VDC at output for some of my LEDs. I will have to feed close to 37V at input to the Vregs. On top of that problem the mains voltage fluctuates from 190Vac to 235Vac so the Tx outputs increase during night times. If this issue becomes an impediment then maybe I will have to build two powersupplies to be used in series :mad:.
Simpler ? : Wouldnt the filter be simpler than the circuit you have in the display. I have 2kg of enameled copper wire lying around already. So some low resistance coils can be made. Beefier filter= more ripple rejection.
Capacitor charging surge at start up : The inductor resists sudden change in current. So an inductor might take care of a large capacitor(>10,000uF) bank lying ahead. So is an inductor better in that place?

The tone of this thread has changed and I may be seen as irrationally leaning towards the filters. But it is not so in reality. I am sort of agnostic. I usually do simple experiments/tests at home and when I build an amp and a filter(my assumptions!) isnt making any difference in blind listening tests, it will be dismantled in a jiffy.

Some more fun:
http://sound.westhost.com/articles/myths.html
http://sound.westhost.com/cables.htm
I work in the area of stock markets. It is the biggest example of human irrationality. I am familiar with it.
 

Thread Starter

prashanthb

Joined May 17, 2015
34
@#12 : LOL !
You may or may not get 10kHz noise out of wall socket. That depends on what other equipments are operating/influencing near the mains lines (inside/outside home). The transformer(silicon steel core) does block HF noise above ~50Khz but then you have diode ringing noise which if it gets coupled with the power rails , will inject HF noise(sometimes upto 3MHz (measured not imaginary!)). The amplitude is quite HIGH!!! Where and how will you attenuate this ?

Any way you will not be getting my CHEQUE because I like Chicken Biryani in my power supply to spice up the music, NOT ORANGE DROPS :p.

@Lestraveled : Can you please go thru LM3886 datasheet and tell if PSRR of 120db is the same for all frequencies ? It generally tends to worsen with increasing frequency it says somewhere here. I generally am agnostic but I feel it is better to take preventive measures....prepare for the bad you see.ALL IT TAKES IS SOME EXTRA TIME. And if it doesnt yield results throw it away and move on to the next probable solution. I usually like/follow what Rod Elliot of ESP says, and he never proposed a filter for the power supply output, but he did caution about transformer stray flux lines re-entering the power lines. I have built 3 amps till date and none of them contain any noise avoidance techniques.
 
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kaiharry12

Joined Jul 9, 2015
1
Unfortunate, but hard to get detached from the desire of experiencing heavenly bliss. The debate to how worthy an effort noise reduction is, is a lengthy and unending one
 

#12

Joined Nov 30, 2010
18,223
@#12 : The transformer(silicon steel core) does block HF noise above ~50Khz but then you have diode ringing noise which if it gets coupled with the power rails , will inject HF noise(sometimes upto 3MHz (measured not imaginary!)). The amplitude is quite HIGH!!! Where and how will you attenuate this ?
1) replace the bad diode
2) expect the 0.1 uf ceramic capacitor in parallel with the larger electrolytic capacitor to shunt that energy to ground.
3) place 1000 pf in parallel with each of the rectifier diodes.
4) Get my ears calibrated so they don't register anything at 3 MHz.
5) attach speakers that do not reproduce sound at 3 MHz.
6) design an amplifier that has a very diminished response at 3 MHz.

The thing is, well educated people have spent decades calculating, designing, and building audio processors, from microphones to speakers, and everything in between, far in excess of the quality a human can detect. I heard the original 24 track master tape of Ventura Highway, played on a 24 track machine, through 400 watt Crown amplifiers into titanium studio monitors, and it made the hair stand up on my neck. Today is 40 years later, and the mere thought of that moment still causes me a physical reaction. When an amateur comes along thinking he has one piece of the puzzle, presented out of context, and which nobody else can imagine a use for, it's a joke. "I have an idea for a filter that will change the definition of audio quality." is like saying, "I can make methane from pig manure pure enough power a craft to Mars." Your design was surpassed and thus made obsolete a hundred years ago.

I enjoy Harry Potter, but I don't use magic in my electronic designs.
 
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Thread Starter

prashanthb

Joined May 17, 2015
34
Ah! now you latched on to the 3MHz number ! Well I agree with 1) 2) & 3).
If that 40 year old sound still lingers on inside you then dont you think I have similar cravings ? Do you think I shouldnt experiment ?
he has one piece of the puzzle, presented out of context, and which nobody else can imagine a use for
You are wrong here. One piece of the puzzle it might be, but it is not out of context.It is being built and used by many. And that is why I am not accepting your statements as the final word. There are others I am listening to. I, as I said before, am stuck between believers and non believers and I will take a decision only after I experience its working.... or its futility & I would never force my views down another persons throat or would never hijack another persons thread.
"I have an idea for a filter that will change the definition of audio quality."
Its your imagination. I never said it will be game changer. I have been agnostic all along.

I am tired ! From my side I will finish this filter issue with one last point. I attended music classes for a brief period. I would see seniors tuning their instruments. I never noticed any change in the sound because I was inexperienced. It requires a trained ear to tune a musical instrument. I never became a musician but I acknowledge this fact and nobody else in this world will deny it. Hard for engineers and mathematicians to notice it, but artists can. The artists can also be correct. Aaaaannnnddddd the chinese markets were falling rapidly and I now see that 45% of the companies listed have suspended trading. What a bogus country china is :mad:. The other markets have responded quite negatively. I must go now to save my investments. Nasa is calling me...errr...my workbench is calling me :) Bye.

With all due respects, thank you all for your contributions.
 
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crutschow

Joined Mar 14, 2008
27,737
Its amazing the bogus advertising they fall for - I once saw advertised, square loudspeakers for digital audio.
And I've seen serious discussions of magical power cords selling for hundreds of dollars that eliminate all that nasty power line noise and improve the "clarity" of the power amplifier it is connected to (which they claim to be able to hear).
 

ian field

Joined Oct 27, 2012
6,539
And I've seen serious discussions of magical power cords selling for hundreds of dollars that eliminate all that nasty power line noise and improve the "clarity" of the power amplifier it is connected to (which they claim to be able to hear).
How do stupid people get hold of so much money to pay for this crap?!!!
 
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