Are these ebay BG capacitor legit? Also requesting IMod Capacitor suggestions. Why are some caps better than others?

[High_Q]

Like I said hobby kits.  Why do you have to show off your projects?  To show you can solder some stuff? All you did was state what they are, and what components you have in them.  I think anybody can build those.  I've been correcting your mistakes because you have incorrectly pointed out something from some hearsay, I don't think thats trolling.  I think trolling is what you have done, trying to correct something that is not wrong, and justifying by making up some concepts you know nothing about.  You are definately a troller qusp.   You have nothing better to do on your time then come on the boards and point out mistakes thats not there.  I wonder how many times you have done that with other people's posts?  And for your defense, you show off circuit boards that you applying your soldering skills on your spare time.  LOL.  Just because you have a lot of circuit boards(premade) and you solder capacitors on them and read the forums on how to do stuff and follow it, doesn't really mean much.  

 

[qusp]

hahaha it still goes on......you say i didnt credit and now i get it for crediting haha wow yeah i confess, youve found me out, the game is up, you ARE SO CLEVER i'm not your equal, i'm not the pre-imminent physicist, pcb designer, diy audio legend, inventor, 'engineer' and general know it all that is clearly in my midst, you win, i bow down before you and i will be your first follower when you release your world beating pcb designs, discover never before understood phenomena; and all in your spare time without using even close to your full potential
 
ive seen the error in my ways, i'll immediately desist from spending vast sums of money impressing people i dont know with something they will never hear with designs that are clearly and deliberately declared not mine.
 
and here was me fooling myself i built it for fun and to listen to music
 
the op is answered, get a grip i call you troll, because that IS what you are

 

[Bop]

I have to say that this thread got a bit ugly . . .

 

[johnwmclean]

Quote:

Just because you have a lot of circuit boards(premade) and you solder capacitors on them and read the forums on how to do stuff and follow it, means really nothing.  

Well actually getting a working circuit from a designer pcb gives me one hell of a buzz, maybe I’m easily amused, as well as a lot of people here on this forum. I recommend before you lash out with your opinionated blanket statements, to think of others and their achievements in diy audio.

 

[High_Q]

 
Quote:

Well actually getting a working circuit from a designer pcb gives me one hell of a buzz, maybe I’m easily amused, as well as a lot of people here on this forum. I recommend before you lash out with your opinionated blanket statements, to think of others and their achievements in diy audio.

Thats great that it gives you great enjoyment.  I apologize if any statements that I have made offended any DIYers. All my comments were directed toward you know who, and for reasons I have stated on my previous posts.  Qusp has been coming off as being very pompous from his first response, and its sad hes coming off that way without clear understanding of things.
 

 

[nikongod]

 
Quote:

The capacitance you need for the diyMod refers to the high pass filter that forms when you connect your diyMod to your amplifier. When you connect a series capacitor to a parallel resistor to ground (in the amplifier, this resistor is the volume potentiometer), it forms a first order high pass filter, which allows passes mostly high frequencies while attenuating low frequencies from the signal. DC power is, all in all, 0 Hz, a low frequency. Capacitance is the amount of charge that the capacitor can hold, and in our use, you only need a small amount of capacitance in the diyMod. The equation governing the size of capacitor in a high pass filter characteristic is

 

C = 1/(2*pi*f*R)

 

where C is the capacitance in uF

f is the frequency in Hz

and R is the input impedance of the amplifier.

 

Basically, we want to filer out the DC while passing as much of the audio signal as necessary. Since humans can typically only hear between 20Hz and 20kHz, the highest  lowest frequency you want to pass through is 20Hz, which we'll plug into the equation.

 

My explaination:

 

 
 

where f is cutoff frequency(meaning that the lower bound cutoff frequency point, since you are letting in high frequencies), and you are passing everything over 20Hz(cutoff frequency).  By doing that you are filtering out DC(which has no frequency, f=0, since its not changing being constant), which is less than 20Hz, everything under 20Hz will not pass.

 

I guess EE school wasn't total waste of time.  

 
With a -3db point of 20hz and a simple first order filter:
What is the attenuation of that circuit at 40hz? 
What is the attenuation at 80hz? 
 
Why are you being such a worthless turd after someone tried to help you with a first-year EE class grade (maybe they even teach it in the physics classes they make premeds go to?) question you posted. As Quisp pointed out there is a hidden problem that you did not necessarily consider. Thats what separates people who have done this sort of stuff from people who have only read about it. Perhaps he used the wrong terminology, but the problem he tried to warn you about is quite real. 
 
Look, pretty pictures! Its like a coloring book, seems like your level.
 

 
With a 0.79uf cap, and a 10Kohm load the -3db point is indeed 20hz! Congratulations, you can do simple math. 
Whats going on in the range up to 80hz? At 80hz there is ~0.5db attenuation, which is an audible ammount, in a totally audible range! There is also pretty wicked phase shift pretty much everywhere.
 

 
Here it is again with a 10uf cap and a 10Kohm load. 
I feel the need to point out that you should look closely at the scale before commenting on the somewhat similar shape of the output response. If you were a little more polite to people who try to help you out maybe Id let you make that entry level mistake but nope. 
 
Anyways, at 20hz with the 10uf cap you have 0.03db of attenuation, and only a few degrees of phase shift. Thats betterr than with the 0.79 cap the perfect equation would suggest. 
 
Now that thats all out there, quisp is STILL right. There is more to life than going to 20hz without much phase shift or attenuation. It seems you have chosen to use an electrolytic cap in your LOD which isnt terrible, but many people would choose to compromise slightly and use a film cap of some sort in a size somewhere in the middle for better quality in the mids and up in exchange for some of the deeeepest bass. 
 
Edited way after the fact:
I said that this was his design. LOL its someone else's design he was picking parts for. 

 

[qusp]

yes, struggling enough to start a thread about the only 2 parts there is any choice with in somebody elses design. thanks for the sims, had mentioned the 3db curve in another post that didnt make it to ink, because i couldnt think of a way to illustrate it without using terminology, or graphic representation that could be construed as someone elses idea.
 
soooo much irony that i think he must be blind to, oh to be that young again

 

[High_Q]

Quote:

 
 
With a -3db point of 20hz and a simple first order filter:
What is the attenuation of that circuit at 40hz? 
What is the attenuation at 80hz? 
 
Why are you being such a worthless turd after someone tried to help you with a first-year EE class grade (maybe they even teach it in the physics classes they make premeds go to?) question you posted. As Quisp pointed out there is a hidden problem that you did not necessarily consider. Thats what separates people who have done this sort of stuff from people who have only read about it. Perhaps he used the wrong terminology, but the problem he tried to warn you about is quite real. 
 
Look, pretty pictures! Its like a coloring book, seems like your level.
 
With a 0.79uf cap, and a 10Kohm load the -3db point is indeed 20hz! Congratulations, you can do simple math. 
Whats going on in the range up to 80hz? At 80hz there is ~0.5db attenuation, which is an audible ammount, in a totally audible range! There is also pretty wicked phase shift pretty much everywhere.
 
Here it is again with a 10uf cap and a 10Kohm load. 
I feel the need to point out that you should look closely at the scale before commenting on the somewhat similar shape of the output response. If you were a little more polite to people who try to help you out maybe Id let you make that entry level mistake but nope. 
 
Anyways, at 20hz with the 10uf cap you have 0.03db of attenuation, and only a few degrees of phase shift. Thats betterr than with the 0.79 cap the perfect equation would suggest. 
 
Now that thats all out there, quisp is STILL right. There is more to life than going to 20hz without much phase shift or attenuation. It seems you have chosen to use an electrolytic cap in your LOD which isnt terrible, but many people would choose to compromise slightly and use a film cap of some sort in a size somewhere in the middle for better quality in the mids and up in exchange for some of the deeeepest bass. 
 
Edited way after the fact:
I said that this was his design. LOL its someone else's design he was picking parts for. 

 
I'm aware of the roll off.  What qusp was talkin about is phase distortions and intermodulation distortions?

  Good one qusp.  What would you guys do if I wasn't here to point out stuff?

 

[rds]

Those graphs show phase distortion.  I don't know why you're talking about IMD.  I've never heard of IMD being a significant issue in passive analog filters.  If you do want to talk about it quantitatively then you'd need to characterize the specific system you're using.  I don't think you can say much about it generally in this case.
 
 
[size=medium]

Quote:

LOL
 
Wow, you see phase?

  Common sense would tell you otherwise..
I'm aware of the roll off.  What qusp was talkin about is phase distortions and intermodulation distortions?

  Good one qusp.  What would you guys do if I wasn't here to point out stuff?

 
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[/size]

 

[High_Q]

Quote:

Those graphs show phase distortion.  I don't know why you're talking about IMD.  I've never heard of IMD being a significant issue in passive analog filters.  If you do want to talk about it quantitatively then you'd need to characterize the specific system you're using.  I don't think you can say much about it generally in this case.

I know, qusp brought up IMD, he heard it on a forum so he used that term here.  I don't know why he brought it up??  Maybe he like to use terms he has no idea about??  Anyway, its f vs dB graph.  That should be enough clue.

 

[nikongod]

 
Quote:

 
Wow, you see phase?

  Common sense would tell you otherwise..
 

Its indicated by the dotted line, and angle is on the right hand side. Sorry that this needs to be pointed out.

 

[High_Q]

 
 
Nikigod, your graphs don't justify anything.  They are just graphs...  Idealistic graphs given that.   Try using a different capacitor, there will be  a difference in phase, just like there is a difference between two capacitors. And based on that can you make a conclusion?  And you are sending a single tone through the filter to as an example? If all signal coming in all have the same delay, there is no distortion.  If on frequency component is out of phase, but not others, that means that the signal has changed.  Now, you think sending a tone tells you anything?
 
 

Phase distortion, Group delay, and Phase delay 
 
 
 

A perfect audio component will maintain the phase coherency of a signal over the full range of frequencies. Phase distortion can be extremely difficult to reduce or eliminate. The human ear is largely insensitive to phase distortion, though it is exquisitely sensitive to relative phase relationships within heard sounds
 
 
Also look up distortion. In lamen terms its change in the original signal. Phase shift is just delay.  In the real world, only delay happen.  You cannnot say a tone has phase distortion.  Its not possible.
 
 
 
 
 
 
 
 

 

[rds]

Quote:

 
 
Try using a different capacitor, there will be  a difference in phase, just like there is a difference between two capacitors. And based on that you can make a conclusion?  And you are sending a single tone through the filter to as an example? If all signal coming in all have the same delay, there is no distortion.  If on frequency component is out of phase, but not others, that means that the signal has changed.  Now, you think sending a tone tells you anything?
 
 
 

 
 
There is no tone being sent in.  Those graphs show frequency response plots.  Based on what you've written above I think you're out of your depth, though I do like what you said about human insensitivity to phase distortion - I also understand this to be the case.  Regardless, it should be minimized in a quality audio device.
 
 
 
 
 

 

[High_Q]

Quote:

Originally Posted by rds /img/forum/go_quote.gif
 
There is no tone being sent in.  Those graphs show frequency response plots.  Based on what you've written above I think you're out of your depth, though I do like what you said about human insensitivity to phase distortion - I also understand this to be the case.  Regardless, it should be minimized in a quality audio device.
 

Nikon pointed out that there is angular units on the vertical axis.  And the shape of the signal is of a single tone.
 

 

[holland]

Quote:

 
 
Try using a different capacitor, there will be  a difference in phase, just like there is a difference between two capacitors. And based on that you can make a conclusion?  And you are sending a single tone through the filter to as an example? If all signal coming in all have the same delay, there is no distortion.  If on frequency component is out of phase, but not others, that means that the signal has changed.  Now, you think sending a tone tells you anything?

 
I suggest you read the plot.  It's idealistic, as it's based on an ideal capacitor and an ideal resistor.  The shift is non-linear with frequency, as such it is distortion.  The use of the term phase distortion is correct.  Different real life capacitors will respond differently, as you noted in your first sentence of the quote.  Audibility of it was not the issue.  The willful introduction of said distortion was.
 
I don't know what exactly it is you are getting at, but you remind me of a number of recent trolls on the boards.  I suggest you try it out and try to prove your points with data instead of being argumentative, with incomplete and unsupported hypothesis.
 
You're obviously googling (as you quoted wiki) and then using those results to try and dominate the discussion as the authority figure.  However, that's failing you immensely, as your behavior is both asinine and immature.  You're obviously a troll as you keyed off of phase distortion as being IMD, admittedly not the same by the poster when called on it, and drove the whole thread into the toilet.
 
If you want to have a meaningful discussion, it would help to drop the attitude, but at this point, it's unclear what exactly it is you are getting at.  Audibility of capacitors?  That's simple, try a few yourself and see for yourself.