rdf asked
Yes. The resonances occur between the PWR and GND planes. It usually doesn't take too much effort to push the resonant frequencies high enough to be of little concern. Certainly not difficult when you know what you are aiming to do.
And Jan Didden has kindly just posted the articles on his website that I referred to earlier and was looking for . I have the originals but couldn't remember where I got them from - probably a tech-on-line feature.
Please read these - they are very informative.
Yes. The resonances occur between the PWR and GND planes. It usually doesn't take too much effort to push the resonant frequencies high enough to be of little concern. Certainly not difficult when you know what you are aiming to do.
And Jan Didden has kindly just posted the articles on his website that I referred to earlier and was looking for . I have the originals but couldn't remember where I got them from - probably a tech-on-line feature.
Please read these - they are very informative.
Bypassing
This guy did an awesome work and measured over 200 bypass cap (and chokes etc.) combinations.
Incredible source!
http://www.diyhifi.org/forums/viewtopic.php?p=25044#p25044
or direct link to file:
http://www.audiofaidate.it/forum/uploaded/caps_tests.zip
Ciao
Tino
This guy did an awesome work and measured over 200 bypass cap (and chokes etc.) combinations.
Incredible source!
http://www.diyhifi.org/forums/viewtopic.php?p=25044#p25044
or direct link to file:
http://www.audiofaidate.it/forum/uploaded/caps_tests.zip
Ciao
Tino
john curl said:
Actually I scavanged one of the best bypass caps I ever used off of 1970's Honneywell HSTTL boards. They were 2.2uF ceramic and could stop just about anything without something smaller in parallel. One of the issues in caps these days is what is the largest value in the smallest SMT footprint.
At RF caps figure a lot into minimizing distortion were you don't have PSRR to help. There are four expensive and large film caps in every ADSL modem since -60dBc was the best they could do without them.
At audio I remain skeptical that the <-120 dB stuff left has any bearing on the perceived sound. From what I read a lot of folks like Dr. Geddes' work so why not repeat his computer generated distortion tests keeping the max THD's below -120dB? I admit to only having skimmed his results but I thought the perception threshholds were quite large.
mrjam said:
You have an enormous about of work in that report. I'm always in awe of anyone with the patience to go that far fully documented. I usually get distrated soon after I start. However I couldn't find any details on the test conditions or instruments. I would appreciate those details. Any pictures of the setup would also help.
scott wurcer said:
now, some believe in extra terristerial = ET (from outer space)
others do not - more down to earth = grounded in facts
where would we put this poor john curl? .. on a scale
one ET believer or more down to earth and the muddy soil we all dwell in
john curl is a mystery to me he takes care of any microscopic detail of technical construction
yet, he believes he can listen and decide his designs details from there
Lineup - really do not get this man called john curl
but still he wouln't want to miss john curl opinions on audio
Regards to all music lovers
named john or anything else more fancy
Regarding -120dB, I am pretty sure we shall have to revise our standards soon. IMHO, according to my experience, -120dB (or -115, -125, who knows exactly) of high order harmonics like 7th, 9th, 11th .... contributes to subjectively worse "sound", compared to gear with "unmeasurable" high order harmonics.
Thank you for making a clear claim. I would like to be one of those proverbial "everyone in the room" that agrees that this is so. If skeptics are excluded from the tests then they lose validity. ABX is not necessary, but taking things into your own private listening room and "living with them" is hard to monitor.
The claims have been made here OTOH that the difference was so immediately obvious that listening to the other choice was not even necessary, in a case where certainly the differences were at the ppm level if even that.
The claims have been made here OTOH that the difference was so immediately obvious that listening to the other choice was not even necessary, in a case where certainly the differences were at the ppm level if even that.
myhrrhleine said:
The degrees of freedom for two time varying voltages are limited, so again we are faced with opening the door for some unknown physics that somehow applies to audio but has been somehow missed by other fields. Again show me some high resolution instrumentation in another industry enhanced by "brilliant pebbles" or Shatki stones or whatever.
PMA said:
Pavel,
Many discveries were made by meticulous observation, testing and validation, disclosure of full test setups, and by giving others the opportunity to repeat them and come to the same conclusion (good!) or not be able to reproduce the phenomenon.
What you and others here give are armchair anecdotes followed by the exclamation: 'prove that it cannot be the case'!
If it wasn't so sad, to hear this from someone who purports to be a logical man of technology, it would be hilarious.
Jan Didden
- Status
- Not open for further replies.