Sound Quality Vs. Measurements - Page 49 - 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 1st January 2012, 10:49 PM   #481
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
Default I see we now have a special audiophile feedback theory - "not intended to be factual"

I'm also glad of wavebourn's diagram - it leaves Thorsten without any wiggle room when he identiifes
Quote:
Yellow is degeneration...
I find Boyk and Sussman's feedback math at odds with Thorsten's claim:
Quote:
...Degeneration lacks the distortion multiplication effect of looped feedback (e.g. shown by Baxandall, Olson et al). According to extant research (Boyk at all) degeneration does in fact lower harmonic distortion for nearly all distortion products (dependent somewhat on circit and device) by the approximately the amount of the degeneration applied, something which looped feedback cannot accomplish.
as can be read from their paper
Attached Images
File Type: png boyk.PNG (100.2 KB, 206 views)

Last edited by jcx; 1st January 2012 at 10:58 PM.
  Reply With Quote
Old 1st January 2012, 10:50 PM   #482
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Quote:
Originally Posted by ThorstenL View Post
Yes, I understand, however, such feedback would not be degeneration, but looped feedback, if it is derived like looped feedback.
If the looped feedback is series derived, what does the output impedance look like? I just want to make sure before we go further that common engineering terms are commonly understood.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 1st January 2012, 11:18 PM   #483
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by scott wurcer View Post
No. 3 needs a source impedance for completeness.
Source and load inmpedances are always in equations. Are we kids, Scott? That diagram was drawn to show kids major basics: feedback by current or by voltage, applied in parallel or in series with input.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE

Last edited by Wavebourn; 1st January 2012 at 11:24 PM.
  Reply With Quote
Old 2nd January 2012, 02:25 AM   #484
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
That is a good part of the 'secret' of my success with the phono preamp.
  Reply With Quote
Old 2nd January 2012, 02:38 AM   #485
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: 96
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 ThorstenL View Post
However, as you persist on making the, repeatedly debunked claim again and again I believe the burden of proof is upon you. So please provide such proof, or with respect, save me the time of having to debunk your claim again.
This does rather seem to me to be totally ****-about-face. In the absence of any claims, feedback is feedback, by observation alone. Your claim that its not in the case of degeneration is special pleading.
__________________
It doesn't have to take the form of a conspiracy, rather a consensus... James H Kunstler
  Reply With Quote
Old 2nd January 2012, 04:47 PM   #486
gk7 is offline gk7
diyAudio Member
 
Join Date: Oct 2007
Location: Vienna, Austria
Quote:
Originally Posted by Wavebourn View Post
I can't. No convenient drawing software for Linux.
...
Downloads | Get The Latest Version of EAGLE | CadSoft EAGLE |

Free for personal use.

Open source:
Main Page - KiCad EDA Suite Official Wiki

Just to name two.
__________________
Regards,
Georg
  Reply With Quote
Old 2nd January 2012, 05:16 PM   #487
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
@Thorsten - that emittor resistor is called since the beginning of the solid-state era feedback resistor. Curent feedback.
The input voltage on the base-emitter is reduced by the negative amount produced via voltage drop on the resistor by the amplified current. It the control theory, any deduction from the input signal (reference) of the output signal, in order to create the error signal, is called fedback. Call it "negative" if you want to point that at the sumation point will be with negative sign/phase compared with the input.
Control theory - Wikipedia, the free encyclopedia

I think you are tempted to call "feedback" only the voltage feedback.

No "denegeration" takes place inside those devices, their parameters remain the same.

Last edited by SoNic_real_one; 2nd January 2012 at 05:19 PM.
  Reply With Quote
Old 2nd January 2012, 06:26 PM   #488
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by gk7 View Post
Thanks, but I meant convenient.
__________________
"Our youth [...] have bad manners, contempt for authority; they show disrespect for their elders, contradict their parents, [...] and tyrannize their teachers. -- Plato, 447-367 BCE
  Reply With Quote
Old 2nd January 2012, 06:46 PM   #489
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
Sonic, you make a good point, but please try to understand what we audio designers are talking about. We have found that LOCAL feedback can sound, and 'maybe' sometimes measure better than GLOBAL LOOP feedback. We are familiar with feedback, and I certainly have been for the last 50 years, when I took my first course in electronics. We have 'been there' and 'tried that'. Only it did not work as well as we predicted it would. That is WHY we have reverted to LOCAL feedback, in many cases, and minimized loop feedback.
The primary difference is that LOCAL feedback is high bandwidth, equal at least, over the entire audio band and perhaps much more. Loop feedback is run on a slope of 6dB/octave, at least somewhere if not everywhere in the audio band. Think it through, and you might see what we have found.
  Reply With Quote
Old 2nd January 2012, 06:55 PM   #490
tvrgeek is offline tvrgeek  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Md
gk7
thanks for the link. I was unaware of this.
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Quality Control differences = variations in sound quality? KT Class D 3 4th June 2014 12:02 AM
Sound Card for Measurements Marik Solid State 2 2nd January 2012 08:59 PM
Sound Card Recommendations (For Audio Measurements) dchisholm Equipment & Tools 5 16th July 2011 09:40 AM
How to protect sound card during amp measurements? okapi Everything Else 13 2nd September 2008 03:06 PM
Sound cards - test and measurements jackinnj Everything Else 2 5th July 2003 03:02 PM


New To Site? Need Help?

All times are GMT. The time now is 04:23 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