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Old 20th January 2006, 05:39 AM   #141
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Default cap DA

Poobah, are you talking about possible IMD, between the (PS residual?) and the O/P? is that what was missed?
 
Old 20th January 2006, 05:44 AM   #142
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I recommend looking at Photo #6 of a 10uf aluminum cap compared to an 8 uf polypropylene cap differentially subtracted with a (nominal) 50k load on both caps in the article: 'A Real-Time Signal Test for Capacitor Quality'. This article can be found on Walt Jung's website.
With a differential test, one can see that the signal difference between the caps lingers many times longer than the original test signal.
It looks like 'smearing' to me, but then, what do I know?
 
Old 20th January 2006, 05:47 AM   #143
poobah is offline poobah  United States
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I guess I wont talk about what is missing (my soundstage is closed) until I investigate... and this will take months. I have no opinion... only suspicions... about the DA issue in caps. On one hand I tend to think people going on about caps are just nutcases... OTOH, there seems to be a pretty fair number of nutcases... more so than speaker wires.

So...



 
Old 20th January 2006, 05:56 AM   #144
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Perhpas it is once again timr for a reminder about Ken Kunderts very good paper about DA from a physical point of view
www.designers-guide.org/Modeling/da.pdf

It is the most comprehensive description i have seen about what DA is, but don't expect any discussion about audio applications there. So far, I have never until this thread seen anybody on the forum disagreeing with the linear model of DA that Kundert, Pease and other use, so whatever DA does to the sound, it is a linear effect, or it isn't caused by DA.
 
Old 20th January 2006, 05:56 AM   #145
poobah is offline poobah  United States
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Actually,

I have most of Jung's books. I took him pretty seriously and still do. But, I read something he "co-authored" on a website about caps/cables or something... it was pretty... uh... uh... well, alot of really stupid adjectives... again. I think he sold/tired out (I have no problem with that...)

May be some of this stuff is true... seems like it shouldn't be rocket science to get to the facts. There is always a 20 year lag between one guy knowing the truth and the rest of us... 'sides, what do I know?

 
Old 20th January 2006, 05:59 AM   #146
poobah is offline poobah  United States
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Christer,

Thanks, I haven't seen that one before...

I'll read it.
 
Old 20th January 2006, 06:34 AM   #147
rdf is offline rdf  Canada
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Quote:
Originally posted by poobah
I have most of Jung's books. I took him pretty seriously and still do. But, I read something he "co-authored" on a website about caps/cables or something... it was pretty... uh... uh... well, alot of really stupid adjectives... again. I think he sold/tired out .....
Hi poobah. You don't mean "Picking Capacitors" by any chance? That 'sell-out' article is over a quarter century old.

http://www.capacitors.com/picking_ca...rs/pickcap.htm
 
Old 20th January 2006, 06:36 AM   #148
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Absolutely agree. If you want absolute transparency, and detail - elimination of signal path C's is imperative. Only, of course, if the rest of the system is similar.

The best capacitor is no capacitor.

Cheers,
Greg
 
Old 20th January 2006, 06:39 AM   #149
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I recommend looking at Photo #6 of a 10uf aluminum cap compared to an 8 uf polypropylene cap differentially subtracted with a (nominal) 50k load on both caps in the article: 'A Real-Time Signal Test for Capacitor Quality'. This article can be found on Walt Jung's website.
With a differential test, one can see that the signal difference between the caps lingers many times longer than the original test signal.
It looks like 'smearing' to me, but then, what do I know?
 
Old 20th January 2006, 08:42 AM   #150
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Guys, we're discussing a preamp, not personalities. Stick to the topic. Off topic posts removed.
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