Discrete Opamp Open Design - Page 115 - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

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 21st September 2012, 06:48 PM   #1141
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
herein lies the rub-- we cannot seem to be able to do a multi tone test that simulates real music without running into testing hardware issues.... issues the ear doesnt have.
  Reply With Quote
Old 21st September 2012, 06:50 PM   #1142
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Quote:
Originally Posted by scott wurcer View Post
Seek and ye shall find. Someone has one good solution. Note this is a formula to yield very low crest factor not a solution for the lowest possible. It looks like you can get near to 2 or so at 31.
Great find! How can this be done in hardware/software? DSP?
Would Audio-Precision be interested as they have implimented multi-tone already?

Last edited by RNMarsh; 21st September 2012 at 06:54 PM.
  Reply With Quote
Old 21st September 2012, 07:13 PM   #1143
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
Praxis from Bill Waslo can do it. You can configure the multi tone generator as you wish.
There is also a new wave generator from Agilent where you can create any waveform in Exel.
  Reply With Quote
Old 21st September 2012, 07:20 PM   #1144
diyAudio Member
 
Joachim Gerhard's Avatar
 
Join Date: Mar 2009
33500 Series Waveform Generator Generating Waveforms from Excel - YouTube
  Reply With Quote
Old 21st September 2012, 07:52 PM   #1145
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally Posted by RNMarsh View Post
Great find! How can this be done in hardware/software? DSP?
Would Audio-Precision be interested as they have implimented multi-tone already?
I think Rich Cabot read that at the time
The makewave utility lets you specify the crest factor you want and then adjusts all levels to avoid clipping to the max output level you spec.

Edit: at AP.com download tech note TN-18.exe (self extracting zip).

jan
__________________
If you don't change your beliefs, your life will be like this forever. Is that good news? - W. S. Maugham
Check out Linear Audio!

Last edited by jan.didden; 21st September 2012 at 08:08 PM.
  Reply With Quote
Old 21st September 2012, 09:16 PM   #1146
RNMarsh is offline RNMarsh  United States
diyAudio Member
 
RNMarsh's Avatar
 
Join Date: May 2012
Location: 2457 Cascade Trail; Cool, CA. 95614
Well lets discuss which one we can all do that works well and start using it on a regular basis. This thd/harmonic, single tone test isn't all of what we are capable of doing and wont help in determining better opamp designs. JC just called and suggests at least a triple tone IM test... better than 2 tone IM. But, lets slug it out here and start using IT.
Which can we all do that doesnt cost the earth and tells us a lot more towards the real application of the opamp - multi-tone signal processing/amplifying. Thx - Dick
  Reply With Quote
Old 21st September 2012, 09:36 PM   #1147
PMA is offline PMA  Europe
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
It is always the same non-linearity. Interpretation of results (Cabot, e.g.). One can take a twin-tone and move it through audio band. Both IM and HD products are visible then.

I would rather suggest a kind of test that is not limited to audio frequencies only. Like audio band sine + AM modulated or FM modulated HF/VHF carrier. This to be analyzed by FFT analysis in audio band and let's see what products were created.
__________________
Pavel Macura
http://web.telecom.cz/macura/audiopage.html
  Reply With Quote
Old 21st September 2012, 10:14 PM   #1148
gpapag is offline gpapag  Greece
diyAudio Member
 
gpapag's Avatar
 
Join Date: Nov 2002
Location: Athens-Greece
Quote:
Originally Posted by Joachim Gerhard View Post
Here is how that measurement works :
Quote:
Originally Posted by PMA View Post
Hi George,
no. Depends on SW used, type of averaging etc
Regards,
Thank you both for replying

George
__________________
["Second Law is a bitch." - SY] ["The Road To Heaven:Specify the performance & accept the design. The Road To Hell:Specify the design & accept the performance"-Bruno Putzeys]
  Reply With Quote
Old 21st September 2012, 10:39 PM   #1149
gpapag is offline gpapag  Greece
diyAudio Member
 
gpapag's Avatar
 
Join Date: Nov 2002
Location: Athens-Greece
Ref. meaningful and implementable audio measurements, I humbly suggest chapters 22,23 from Bob Cordell book.

George
Attached Images
File Type: jpg contents.jpg (123.0 KB, 328 views)
__________________
["Second Law is a bitch." - SY] ["The Road To Heaven:Specify the performance & accept the design. The Road To Hell:Specify the design & accept the performance"-Bruno Putzeys]
  Reply With Quote
Old 23rd September 2012, 05:24 PM   #1150
diyAudio Member
 
scott wurcer's Avatar
 
Join Date: Jan 2004
Location: cambridge ma
Quote:
Originally Posted by Joachim Gerhard View Post
Praxis from Bill Waslo can do it. You can configure the multi tone generator as you wish.
There is also a new wave generator from Agilent where you can create any waveform in Exel.

You can use Excel and SoX to directly create .wav files at any resolution and sample rate supported.
__________________
"The question of who is right and who is wrong has seemed to me always too small to be worth a moment's thought, while the question of what is right and what is wrong has seemed all-important."
  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
Discrete OPAMP audio-gd Vendor's Bazaar 27 20th September 2012 04:02 PM
discrete opamp help blackpowderaudio Parts 0 16th December 2009 03:46 PM
THAT transistor headphone amp (250ma discrete opamp) design sanity check. Russ White Headphone Systems 19 13th December 2007 12:52 PM


New To Site? Need Help?

All times are GMT. The time now is 01:29 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