Okay. I understand now.
B*A0*sin(omega*t-phi) + C*A0*sin(omega*t-phi-theta)
can be expressed as
D*A0*sin(omega*t-phi+rho)
where D and rho are some function on B,C, and theta.
Since pictures are worth a thousand words, maybe the image below will help others like me. Blue and purple traces are equivilent to sin(x) and sin(2x), green and brown to sin(x)+0.25*sin(x+(pi/2)) and sin(2x)+0.25*sin(2x+(pi/2)). It should be clear that the above relation holds, and moreso that rho has a linear relationship with omega.
B*A0*sin(omega*t-phi) + C*A0*sin(omega*t-phi-theta)
can be expressed as
D*A0*sin(omega*t-phi+rho)
where D and rho are some function on B,C, and theta.
Since pictures are worth a thousand words, maybe the image below will help others like me. Blue and purple traces are equivilent to sin(x) and sin(2x), green and brown to sin(x)+0.25*sin(x+(pi/2)) and sin(2x)+0.25*sin(2x+(pi/2)). It should be clear that the above relation holds, and moreso that rho has a linear relationship with omega.
Attachments
comb filter
A circuit that adds a delayed version of a signal to the signal is linear so it doesn't suffer from nonlinear distortion like THD, IM, etc, but it functions as a comb filter.
By that, I mean that it has a frequency response that is zero for every frequency that is an odd multiple of 1/(2*Tdelay) and 2 for every frequency that is an even multiple of 1/(2*Tdelay), going up and down in between.
A circuit that adds a delayed version of a signal to the signal is linear so it doesn't suffer from nonlinear distortion like THD, IM, etc, but it functions as a comb filter.
By that, I mean that it has a frequency response that is zero for every frequency that is an odd multiple of 1/(2*Tdelay) and 2 for every frequency that is an even multiple of 1/(2*Tdelay), going up and down in between.
Re: comb filter
Interesting discussion. It may be helpfull to remember that distortion can be both linear and nonlinear. If we talk about THD or TIM that is nonlinear distortion because as a result of the nonlinear transfer function, the output contains (freq) components that were not in the input.
Linear distortion does not add any new components but refers to deviations in the freq response or phase shifts etc.
I'm sure you are all aware of that, but I get the feeling there is sometimes a disconnect in the discussions.
Jan Didden.
mirlo said:
Interesting discussion. It may be helpfull to remember that distortion can be both linear and nonlinear. If we talk about THD or TIM that is nonlinear distortion because as a result of the nonlinear transfer function, the output contains (freq) components that were not in the input.
Linear distortion does not add any new components but refers to deviations in the freq response or phase shifts etc.
I'm sure you are all aware of that, but I get the feeling there is sometimes a disconnect in the discussions.
Jan Didden.
Yeah, that was going to be my point. As long as DA is purely linear, it will not show up as HD. Furthermore, as Tiroth pointed out, the sum of directly and DA-transmitted signal can be expressed at a given frequency as B*A0*sin(omega*t - phi - theta) or something the ike.
I don't think we need to worry that DA-induced theata will be different at any other frequence and because this won't cause smearing.
When DA becomes nonlinear that is when we smearing and other nasty effects might take place.
I don't think we need to worry that DA-induced theata will be different at any other frequence and because this won't cause smearing.
When DA becomes nonlinear that is when we smearing and other nasty effects might take place.
<hr width="95%" align=center><i><font color=#800080>polystrene is best, but no one makes 'em anymore...</font></i><hr width="95%" align=center>
<b><a href="http://www.americancapacitor.com/">American Capacitor Corporation</a></b> serves the film capacitor market with both high volume catalog styles and special designs. Film capacitors can be supplied in all dielectric systems, including SuperMetallized Polypropylene, Metallized Polypropylene, Metallized Polycarbonate, Metallized Polyester, Metallized Mylar, SuperMetallized PolyPulse, Metallized Polysulfone, Metallized Teflon, Metallized Paper, Polypropylene & Foil, Polycarbonate & Foil, Polyester & Foil, Mylar & Foil, PolyPulse & Foil, Polysulfone & Foil, <b><u><a href="http://www.americancapacitor.com/capacitors/polystyrene/Polystyrene.htm">Polystyrene & Foil</a>,</u></b> Teflon & Foil, Mica & Foil, Paper & Foil and other dielectrics and dielectric systems. <hr width="95%" align=center>
<a href="http://www.audience-av.com/on_capacitor_dielectric_material.htm">On Capacitor Dielectric Materials - A Chemist's View
Karl A. Weber, Ph.D.</a>
Regards
James
<b><a href="http://www.americancapacitor.com/">American Capacitor Corporation</a></b> serves the film capacitor market with both high volume catalog styles and special designs. Film capacitors can be supplied in all dielectric systems, including SuperMetallized Polypropylene, Metallized Polypropylene, Metallized Polycarbonate, Metallized Polyester, Metallized Mylar, SuperMetallized PolyPulse, Metallized Polysulfone, Metallized Teflon, Metallized Paper, Polypropylene & Foil, Polycarbonate & Foil, Polyester & Foil, Mylar & Foil, PolyPulse & Foil, Polysulfone & Foil, <b><u><a href="http://www.americancapacitor.com/capacitors/polystyrene/Polystyrene.htm">Polystyrene & Foil</a>,</u></b> Teflon & Foil, Mica & Foil, Paper & Foil and other dielectrics and dielectric systems. <hr width="95%" align=center>
<a href="http://www.audience-av.com/on_capacitor_dielectric_material.htm">On Capacitor Dielectric Materials - A Chemist's View
Karl A. Weber, Ph.D.</a>
Regards
James
I stand corrected
Xicon passive components are carried by Mouser. Here's the link to Xicon's PS cap page:
http://www.xicon-passive.com/specs/23p.pdf
Xicon passive components are carried by Mouser. Here's the link to Xicon's PS cap page:
http://www.xicon-passive.com/specs/23p.pdf
Capacitor hysterisis
I was reading over the product descriptor for the LF398 sample-and-hold circuit and the term came up early in the discussion, particularly with respect to ceramic capacitors. Of course, for an s/h you really want a high quality hold capacitor.<p> Hysterisis, of course, is useful in motor and relay control etc., when you don't want things chattering away. With respect to capacitors, however, I wonder if the term relates to some non-exponential decay component ...
I was reading over the product descriptor for the LF398 sample-and-hold circuit and the term came up early in the discussion, particularly with respect to ceramic capacitors. Of course, for an s/h you really want a high quality hold capacitor.<p> Hysterisis, of course, is useful in motor and relay control etc., when you don't want things chattering away. With respect to capacitors, however, I wonder if the term relates to some non-exponential decay component ...
Hi all,
IMHO, a capacitor *changes* character sound and tonality, I have heard this some times.
Static measurement of distortion of a capacitor, a 1kHz sinewave I believe is nonsense.
Look that schematics:
With proper values of parts, if measured with a 1kHz "static" sinewave, no distortion is detected at all. If you put a erratic signal (as music) very distorted sound will obtained, as capacitor charge and discharge, looks "memory distortion".
Some measures about non-linearities in capacitors can find in Steve Bench pages (Sound of capacitors)
With Pspice is possible to emulate Steve's method, and diodes (union PN capacitance) can aproximate these phenomena.
Regards,
luis maría cárdaba
IMHO, a capacitor *changes* character sound and tonality, I have heard this some times.
Static measurement of distortion of a capacitor, a 1kHz sinewave I believe is nonsense.
Look that schematics:
An externally hosted image should be here but it was not working when we last tested it.
With proper values of parts, if measured with a 1kHz "static" sinewave, no distortion is detected at all. If you put a erratic signal (as music) very distorted sound will obtained, as capacitor charge and discharge, looks "memory distortion".
Some measures about non-linearities in capacitors can find in Steve Bench pages (Sound of capacitors)
With Pspice is possible to emulate Steve's method, and diodes (union PN capacitance) can aproximate these phenomena.
Regards,
luis maría cárdaba
Crossover caps
All of the above posts must be relevant to crossover caps as well. If you want several tens of microfarads and ignore bipolar electro's, what would you normally use? How would AC power factor caps like used in fluorescent light fittings go? I think they are metallised polycarbonate. Also, AC motor run (not start!) caps? The ones I looked at were metallised polypropylene. I have no idea what the equivalent series inductance of them would be. It might be awful seeing they are really intended for ac mains usage. The good thing about them is that they are readily available in a wide variety of sizes and good prices, particularly the fluoro light ones.
GP.
All of the above posts must be relevant to crossover caps as well. If you want several tens of microfarads and ignore bipolar electro's, what would you normally use? How would AC power factor caps like used in fluorescent light fittings go? I think they are metallised polycarbonate. Also, AC motor run (not start!) caps? The ones I looked at were metallised polypropylene. I have no idea what the equivalent series inductance of them would be. It might be awful seeing they are really intended for ac mains usage. The good thing about them is that they are readily available in a wide variety of sizes and good prices, particularly the fluoro light ones.
GP.
Maybe Ok.....
"I have no idea what the equivalent series inductance of them would be. It might be awful seeing they are really intended for ac mains usage. The good thing about them is that they are readily available in a wide variety of sizes and good prices, particularly the fluoro light ones."
Considering that they are intended for relatively high power applications, the ESR is likely reasonably low.
Series inductance is likely reasonably low too.
I have not tried A/B comparisons, but I have seen inside high power PA cabinets with flouro type caps.
Eric.
"I have no idea what the equivalent series inductance of them would be. It might be awful seeing they are really intended for ac mains usage. The good thing about them is that they are readily available in a wide variety of sizes and good prices, particularly the fluoro light ones."
Considering that they are intended for relatively high power applications, the ESR is likely reasonably low.
Series inductance is likely reasonably low too.
I have not tried A/B comparisons, but I have seen inside high power PA cabinets with flouro type caps.
Eric.
Metallized Polycarbonate (MKC)
I have had that feeling myself, that MKC capacitors
could be very useful in the signal chain.
Unfortunatly they are a little expensive.
As I have a low Wth value (see Thread "heat issues" in Pass)
I have not tried them, yet.
One must not destroyed them with to much soldering heat.
Any useful experiences?
I have had that feeling myself, that MKC capacitors
could be very useful in the signal chain.
Unfortunatly they are a little expensive.
As I have a low Wth value (see Thread "heat issues" in Pass)
I have not tried them, yet.
One must not destroyed them with to much soldering heat.
Any useful experiences?
Polycarbonate film capacitors will be going away as
the manufacture of the film is discontinuing it.
Polystyrene has gone away and anyone still
making them is doing so from a dwindling stockpile.
See Cyril Bateman's latest EW article on capacitors
for some encouraging remarks about the relatively
new PPS film.
the manufacture of the film is discontinuing it.
Polystyrene has gone away and anyone still
making them is doing so from a dwindling stockpile.
See Cyril Bateman's latest EW article on capacitors
for some encouraging remarks about the relatively
new PPS film.
Re: Crossover caps
My expectations were not great, and the rest of the crossover is full of Hovlands, which were there when I bought the speakers, but they're fine. A bit screechy for a couple of hours but settled down OK, and I don't think I'd bother to spend a hundred bucks to replace them with Solens.
Give them a try.
I'm using some 35u/250Vac metalised PP caps in my crossover at the moment. This isn't a permanent setup but they were the right value and price ($A2 ea new) so I gave them a try. I bought them to use in the first stage of an LCLC PSU for my linestage, where they seem to work very well.Circlotron said:
My expectations were not great, and the rest of the crossover is full of Hovlands, which were there when I bought the speakers, but they're fine. A bit screechy for a couple of hours but settled down OK, and I don't think I'd bother to spend a hundred bucks to replace them with Solens.
Give them a try.
Thanks BrianLBrianL said:
I am now searching the web for the article you mention.
I found this link with PPS - PP sulfide capacitors
http://www.toray.co.jp/e/plastics/products/pps/index.html
Lexan film going away?
I searched GE's website and there's no release to the fact that Lexan (polycarbonate) films are going away although any compounder could decide to abandon their line due to lack of demand. The plastics business in one of the real gems of General Electric. <p> It will be news to Dow Chemical that there's no demand for polystyrene anymore. Dow also manufactures polycarbonates under the Calibre brand. In fact, Dow lusted for the end of certain GE patents so they could get into this resin.
I searched GE's website and there's no release to the fact that Lexan (polycarbonate) films are going away although any compounder could decide to abandon their line due to lack of demand. The plastics business in one of the real gems of General Electric. <p> It will be news to Dow Chemical that there's no demand for polystyrene anymore. Dow also manufactures polycarbonates under the Calibre brand. In fact, Dow lusted for the end of certain GE patents so they could get into this resin.
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