Good morning all..... you can figure out your answer if you look at all the 'other factors' one by one first. But dont just go by simplified models. I pointed out one area that isnt modeled near the self res freq.
'other factors' to eliminate --- if a transient/pulse excites that resonance... does it produce distortion? I dont know - because I havent seen a model to tell if it non-linear in that region.
I have seen the ringing waveform look distorted with some dielectrics. But that's for another time and I dont want to spoil your fun.
Temp changes to various parameters (DF) are not included in cap models, either. Neither is esr modulation with current/freq. And, there are no distortion models... even polar cap models are overly simplified esp in regard to potential for distortion. But we can measure all these things.
THx-RNMarsh
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I think that Richard is trying for the upside in all of this.
However, Richard has mentioned how he got his 'non-linear distortion' from DA in the cap. He does not have to repeat the experience, or show greater details, especially to people who do not have access to similar test equipment.
Second, Scott Wurcer did once get a SIMILAR DA waveform from a computer simulation using paralleled LINEAR RC's as shown by Dow et al, back in the 50's and 60's when analog computers dominated the simulation world. The LINEAR model is only a MODEL, a best fit, and it is NOT derived from first order causes. I have a copy of Scott Wurcer's work around here somewhere, and it is ONLY an approximation of what we actually MEASURE, doing an actual equivalent measurement to what Scott modelled on the computer. Perhaps Scott did further work to prove his assertion that the model is completely accurate, but I know what I have seen from him so far, is only an approximation. That is what we expect from models.
However, Richard has mentioned how he got his 'non-linear distortion' from DA in the cap. He does not have to repeat the experience, or show greater details, especially to people who do not have access to similar test equipment.
Second, Scott Wurcer did once get a SIMILAR DA waveform from a computer simulation using paralleled LINEAR RC's as shown by Dow et al, back in the 50's and 60's when analog computers dominated the simulation world. The LINEAR model is only a MODEL, a best fit, and it is NOT derived from first order causes. I have a copy of Scott Wurcer's work around here somewhere, and it is ONLY an approximation of what we actually MEASURE, doing an actual equivalent measurement to what Scott modelled on the computer. Perhaps Scott did further work to prove his assertion that the model is completely accurate, but I know what I have seen from him so far, is only an approximation. That is what we expect from models.
I did email Bateman asking about his reasoning re DA and his seeming to say there was a causal link to nonlinear distortion
he was rather offended at the questioning - perhaps he thought I was questioning his data - never addressed my actual question
we do measure nonlinear distortions in caps, and we can measure DA - maybe we can plot them but there rare relatively few "points" - dielectrics that are already good enough to meet various engineering needs and be economically manufacturable
once again mr Curl can't seem to separate logical/techinical issues - goes with the personal story, defend friend's work blindly
seem to be a theme
he was rather offended at the questioning - perhaps he thought I was questioning his data - never addressed my actual question
we do measure nonlinear distortions in caps, and we can measure DA - maybe we can plot them but there rare relatively few "points" - dielectrics that are already good enough to meet various engineering needs and be economically manufacturable
once again mr Curl can't seem to separate logical/techinical issues - goes with the personal story, defend friend's work blindly
seem to be a theme
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Yes, one of the factors discussed somewhere in diyaudio (maybe somewhere in this thread) was how the construction techniques of film capacitors may be as or more important than the dielectric material.
Harman used to implement the elaborate EQs for specific OEM automotive amplifiers using gobs of Panasonic stacked-film PET capacitors and metal-film resistors and op amps. The caps were good parts, and the QA folk were pleased at the distributions unless things had been stretched a bit for some difficult peaking or dipping (questionably high Q, usually, but the fine-tuning for a vehicle interior was done in another part of the company).
But there were some reservations, and Rich May quietly opined that the wrapped axial PET caps, typically made in Taiwan, were sonically superior. He also expressed the notion that the tensioning machines for winding film caps were crucial to the capacitor quality.
Now all is done in DSP.
Just being devil's advocate for a second here, too. is it well below 1/10th dB? ---
Using a wide/broad band signal (noise) source, F.Toole found that 1/10db change was reliably heard/detected. Could that be what is heard if =/> 1/10th dB is caused by DA??
THx-RNMarsh
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Hi SyncTronX,
Some times there is a part number on the chassis (the CD transport proper) that would also help. Expect to find that at the rear on on the side of the transport somewhere.
If something is sitting on my own bench, recognizing these things tends to be a lot easier to do. I'll also admit that with so much trash out there, I had lost interest in that component type, although Cyrus is supposed to have designed their own a couple years ago. I haven't seen that one yet, but I would love to play with one on the bench! The ones they just ran away from were the lovely Chinese Philips VAM series (utter trash!).
-Chris
Either the transport is clearly called out in the parts list, probably in the mechanical blow up, or to be safe, take pictures of the transport and an underneath shot showing the head on its rails. Showing the electrical stuff on the back / side can be helpful.
Some times there is a part number on the chassis (the CD transport proper) that would also help. Expect to find that at the rear on on the side of the transport somewhere.
If something is sitting on my own bench, recognizing these things tends to be a lot easier to do. I'll also admit that with so much trash out there, I had lost interest in that component type, although Cyrus is supposed to have designed their own a couple years ago. I haven't seen that one yet, but I would love to play with one on the bench! The ones they just ran away from were the lovely Chinese Philips VAM series (utter trash!).
-Chris
I have discussed this aspect of quality and its meaureable affects. But, yes, slow tight winding is needed for high reliability but thru-put is low that way... So, only fast winding is done for lowest competitive price. fast winding traps air between layers which reduces the voltage rating/reliability.... arc-over occures at the air pockets.
And loose windings can cause small measurable C modulation under the right conditions.
As for ceramic caps..... note before all this, ceramics were used for the Cdom stability caps in audio circuits!
THx- RNMarsh
Eliminating pathological capacitors, I would say less than that. That table of pre-amps from last week had far worse variance in RIAA conformance than .1dB.
Well, that's all well and good, but my question still is, how did you attribute the harmonics you saw to DA, as opposed to any other factors?
Scott,
Do you have any measurements?
The paper showed a polystyrene cap where the model's shunt capacitors were .1% of the base value. As that was one of the best it would not surprise me to see a paper/oil capacitor (with a "warm" sound noted by some) easily getting to a few percent or more for the mode'ls shunt capacitors. (Having used high voltage oil capacitors it wouldn't even surprise me to see some of the shunt capacitors to be larger than the base value!)
ES
Says who? You? Who are you? All I know about you is that people mostly buy your expensive cables hoping they will improve the sound. Otherwise, you would have on your web site.... my cables are only for looks and are reliable but they wont have any affect on your sound. Watch what happens to your audiophile sales/income after that.
I did my research and made my conclusion. Doesnt fit your model of the world? I'm sooo sorry for that. Otherwise, your opinion doesnt matter.
Have a nice day
THx-RNMarsh
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I worked on that assembly line for about a year in '87. 4 channel amps for Ford production cars. Brad Plunkett was the engineering face I always saw.
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Richard - whats wrong with the engineering answer - show us a audio application where DA is causing 1/10 dB deviation in frequency response
the measurement is quite doable with a soundcard
the models of even Mylar would give micro to maybe single digit milli dB in audio circuit apps I'm familiar with - not 1/10th dB
https://web.archive.org/web/20051226052157/http://www.national.com/rap/Application/0,1570,28,00.html
shows the linear circuit model - should give the audio frequency DA "linear distortion" when use in a Spice sim
.1% = .01dB. Not really interested in the sound of vintage capacitors, all DSP now.
OK. I know that's a real issue... inaccurate RIAA. For hi-end, they should know and do better. But, then again, how will is the RIAA at the cutter end to the published numbers? is it better than 0.1dB. People didnt know we could hear that well back in those days of cutter system design.
But still off the mark or not..... an added .1db by DA against no DA would be noticable if 0.1dB difference was caused by DA. I dont know the answer.
-RM
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