John Curl's Blowtorch preamplifier part II - Page 3102 - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th December 2012, 08:23 AM   #31011
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by VladimirK View Post
Not these approaches.
In your later post, you have mentioned direct error extraction between output and proper time shifted input, two voltages at a given time moment. If somebody will manage to achieve -160dB accuracy in this way (like Ed Simon did with resistors measurements), this will be real advance in applied sound reproduction studies. Why -160dB ? Resistors are quite listenable, but their measurable artefacts are around -160dB only. Similar numbers, I guess, are associated with capacitors, contacts, wiring, etc.
Bill Waslo's Diffmaker software does just that. He has some test files on his website where one track classical music has a complete sousa-band buried in it at -60db and most people cannot hear it untill the main music is stripped off.

Ed Simon's article in Linear Audio Vol 0 shows resistor nolinearity varying from -60 or -80 dB to a formidable -160 dB. The facts 1) that the best resistors manage -160 dB and 2) some resistors cause audible diferences does not lead to a logical conclusion that we can hear -160 dB nonlinearity. Bill Waslo shows that you are a factor of 100,000 too optimistic

jan
__________________
I won't make the tactical error to try to dislodge with rational arguments a conviction that is beyond reason - Daniel Dennett
Check out Linear Audio Vol 7!
  Reply With Quote
Old 7th December 2012, 08:40 AM   #31012
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: cambridge ma
Quote:
Originally Posted by VladimirK View Post
Why -160dB ? Resistors are quite listenable, but their measurable artefacts are around -160dB only. Similar numbers, I guess, are associated with capacitors, contacts, wiring, etc.
False logic. See what you have done Ed.

EDIT - Missed you comment Jan at least it's a sane hour where you are.
__________________
Silence is so accurate.

Last edited by scott wurcer; 7th December 2012 at 08:43 AM.
  Reply With Quote
Old 7th December 2012, 08:45 AM   #31013
The Dastardly Dad of Three
diyAudio Member
 
Join Date: Sep 2009
Quote:
Originally Posted by ticknpop View Post
My phono input uses matched 4 x 2SK147 and 4 x 2SJ72 per channel plus cascodes - bought them from Erno 20 years ago in the golden age of jfets. What is left for designers today ? BF 852 and waiting for Linear Devices to make a P channel device or do we go over to the dark side and use bipolars. Any sign of a surface mount N or P dual low noise jfet pair or is it all cell phone and computer chips and we are doomed to trolling Hong Kong Ebay sites for fake jfets forever?
sorry to intrude - but wonder if any decent P channel SMT JFETS have become available so we have a nice complement to the BF 852/862 ? Thought it might be nice to make some buffers with them. I could not find anything searching through this thread other than the above ref.... Thanksamillion for any guidance
  Reply With Quote
Old 7th December 2012, 09:03 AM   #31014
diyAudio Member
 
Join Date: Feb 2007
Location: Tashkent
Quote:
Originally Posted by Esperado View Post
Well, the maximum level our ears are able to afford is 120dB spl. Where do you put those 'quite listenable' -40dB ?
I did not investigate this subject personally, but if some assumptions contradics "experiment", try to suppose what could be wrong with current axioms, and not simply discard the "experimental" result.
I could suppose, that listenability depends on circumstances. Addition of very small fraction of definite distortion COULD BE listenable (difference between two signals), while distortion signal alone - not. I do not know exactly, but we must research for getting explainations.
On the contrary, I could ask you: please, give an idea, why a resistor type used at GNFB is quite listenable, while it adds THD portion of -120 -160dB level?
I understand, that an easiest position to say, that they CAN NOT BE LISTENABLE because of 120dB of dynamic range. But they are listenable.

Last edited by VladimirK; 7th December 2012 at 09:06 AM.
  Reply With Quote
Old 7th December 2012, 09:03 AM   #31015
diyAudio Member
 
Esperado's Avatar
 
Join Date: Jul 2011
Location: France
Quote:
Originally Posted by jan.didden View Post
Ed Simon's article in Linear Audio Vol 0 shows resistor nolinearity varying from -60 or -80 dB to a formidable -160 dB.
How can we TEACH audiophiles how to land in the REAL world ?
And give them elementary notion of the orders of magnitude ?
I read that, and it is just a confirmation that resistors are perfect, while some begin to worry about the way they... sound !
__________________
Ultimate Protection and more.The Only Source of Knowledge is experience, everything else is just information” ©A. Einstein
  Reply With Quote
Old 7th December 2012, 09:10 AM   #31016
diyAudio Member
 
Esperado's Avatar
 
Join Date: Jul 2011
Location: France
Quote:
Originally Posted by VladimirK View Post
I understand, that an easiest position to say, thay they CAN NOT BE LISTENABLE because of 120dB of dynamic range. But they are listenable.
Some resistors (carbon) adds are a little noisy (more noise than the thermal one of a *perfect resistor*). They can vary a little their values with temperature. I'm not able to ear any change of 'sound' from a metallic resistor. It is just like worrying about a temperature change of 1/100 ° of your body.
To put the things in perspective, the best loudspeakers have a distortion > -40db under the signal level.

Now, worry if you *like* to worry and convince-you that "they are listenable", we have no power against such convictions.
__________________
Ultimate Protection and more.The Only Source of Knowledge is experience, everything else is just information” ©A. Einstein

Last edited by Esperado; 7th December 2012 at 09:17 AM.
  Reply With Quote
Old 7th December 2012, 09:10 AM   #31017
diyAudio Member
 
Join Date: Feb 2007
Location: Tashkent
Quote:
Originally Posted by jan.didden View Post
Bill Waslo's Diffmaker software does just that. He has some test files on his website where one track classical music has a complete sousa-band buried in it at -60db and most people cannot hear it untill the main music is stripped off.
Dear Jan, I believe it is so, but what kind of audio system did Waslo use?
With computer attached speakers, many things can happen.
To start with, one should
- use really top rank system ("acoustic oscilloscope")
- got enough experience in listenings of high quility recordings.
  Reply With Quote
Old 7th December 2012, 09:14 AM   #31018
diyAudio Member
 
Join Date: Feb 2007
Location: Tashkent
Quote:
Originally Posted by Esperado View Post
Some resistances (carbon) adds are a little noisy (more noise than the thermal one of a *perfect resistor*). They can vary a little their values with temperature. I'm not able to ear any change of 'sound' from a metallic resistor. It is just like worring about a temperature change of 1/100 ° of your body.
To put the things in perspective, the best loudspeakers have a distortion > -40db under the signal level.
We must not generalize distortions, one kind of distortion does not attract care at -40dB level, while another is listenable even at -20dB below noise floor. Therefore, in my "personal" qualitative picture of "audio world" there are "macro sound picture" and "micro sound picture".
The first is well studied, while the second exists below limits of resolution of 99% of systems that people use. Therefore, not everybody understand, what "micro sound picture" is. I do not claim, that the last is not measurable, but it requires more advanced techniques for correct measurements, than standard ones.

Last edited by VladimirK; 7th December 2012 at 09:20 AM.
  Reply With Quote
Old 7th December 2012, 09:37 AM   #31019
KSTR is offline KSTR  Germany
diyAudio Member
 
KSTR's Avatar
 
Join Date: Jul 2007
Location: Central Berlin, Germany
Quote:
Originally Posted by jan.didden View Post
Bill Waslo's Diffmaker software does just that. He has some test files on his website where one track classical music has a complete sousa-band buried in it at -60db and most people cannot hear it untill the main music is stripped off.
It's a strawman test because this is just uncorrelated random noise which we are able to filter out completely. If we couldn't, we would not at all be able listen to any music faithfully without living in a fully sound-proofed room.

Repeat the test with a correlated distorted copy of the original and you'll be surprised.
  Reply With Quote
Old 7th December 2012, 09:42 AM   #31020
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 99
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
Quote:
Originally Posted by KSTR View Post
It's a strawman test because this is just uncorrelated random noise which we are able to filter out completely. If we couldn't, we would not at all be able listen to any music faithfully without living in a fully sound-proofed room.

Repeat the test with a correlated distorted copy of the original and you'll be surprised.
+1 - I was just about to post the same, but you beat me to it Klaus I'm guessing this 'test' was one dreamed up by Ethan Winer?
__________________
It doesn't have to take the form of a conspiracy, rather a consensus... James H Kunstler
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 10:46 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2