Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Blameless THD
Blameless THD
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 16th January 2010, 09:37 AM   #1
nicholas1113 is offline nicholas1113  Malaysia
diyAudio Member
 
Join Date: Nov 2009
Default Blameless THD

Hey
I really need some help with my high THD ... i really dunno what happen to my High THD can anyone help me giving me some advise with 10hz THD is 0.0006% .. but i simulated a 73% for the Blameless power Amplifier.

I really need some help since I have stucked.

Below is the Blameless.asc and also the Diagram of the THD result .
Mind everyone for the help!

ClassB(THD8ohm).txt
121212123.JPG
  Reply With Quote
Old 16th January 2010, 10:18 AM   #2
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
add .options plotwinsize = 0 to your spice diagram. also you will have to simulate at a small timestep like 0.05u.

Post your LTSPICE .ASC file and we can help more
  Reply With Quote
Old 16th January 2010, 10:39 AM   #3
megajocke is offline megajocke  Sweden
diyAudio Member
 
megajocke's Avatar
 
Join Date: Jan 2003
The models used were not included so I couldn't test your simulation but with a simulation length of only 15ms you are not going to get any information on the 10Hz distortion.
  Reply With Quote
Old 16th January 2010, 11:26 AM   #4
godfrey is offline godfrey  South Africa
diyAudio Member
 
Join Date: Nov 2009
Location: Cape Town
This gives sensible results:

.four 0.01kHz V(OUTPUT)
.tran 0 500m 100m 0.1m
  Reply With Quote
Old 16th January 2010, 12:18 PM   #5
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Well, the output clearly shows he's simulating 10kHz, not 10Hz. That's a much more reasonable number.

Likely you're DC-operating points are completely banana.

Always distrust the computer.

Have fun, Hannes
  Reply With Quote
Old 16th January 2010, 12:25 PM   #6
megajocke is offline megajocke  Sweden
diyAudio Member
 
megajocke's Avatar
 
Join Date: Jan 2003
Oh, that's right too. There is a mismatch between the signal source which was set to 10 Hz and the .four command set to 10 kHz.
  Reply With Quote
Old 17th January 2010, 12:45 PM   #7
nicholas1113 is offline nicholas1113  Malaysia
diyAudio Member
 
Join Date: Nov 2009
Quote:
Originally Posted by h_a View Post
Well, the output clearly shows he's simulating 10kHz, not 10Hz. That's a much more reasonable number.

Likely you're DC-operating points are completely banana.

Always distrust the computer.

Have fun, Hannes

What does it mean by DC-operating points are completely banana?
How does it know ?
  Reply With Quote
Old 17th January 2010, 12:46 PM   #8
nicholas1113 is offline nicholas1113  Malaysia
diyAudio Member
 
Join Date: Nov 2009
Quote:
Originally Posted by jaycee View Post
add .options plotwinsize = 0 to your spice diagram. also you will have to simulate at a small timestep like 0.05u.

Post your LTSPICE .ASC file and we can help more
I have post the .txt file and you can change to .asc .
thank you
  Reply With Quote
Old 17th January 2010, 12:52 PM   #9
nicholas1113 is offline nicholas1113  Malaysia
diyAudio Member
 
Join Date: Nov 2009
Quote:
Originally Posted by godfrey View Post
This gives sensible results:

.four 0.01kHz V(OUTPUT)
.tran 0 500m 100m 0.1m
Ya man ... the THD is lower but it should be 0.0006% in the BLameless ..
IS the input voltage frequency should be same as 0.01K for the command of
.four 0.01kHz V(OUTPUT)?
Are they the same?
  Reply With Quote
Old 17th January 2010, 02:07 PM   #10
h_a is offline h_a  Europe
diyAudio Member
 
h_a's Avatar
 
Join Date: Sep 2006
Location: Graz, Austria
Quote:
How does it know ?
Any amp you want to simulate you need to know very well first. You need to understand how it works and what the DC-working points (currents, voltages) are. Otherwise you cannot be sure that the results are worth the time you needed to generate them. A simulator does not replace basic understanding of the circuit.

However, first you should read the wikipedia-article on distortion

I'm sure then it's more clear what signal to put in (1kHz) and what to analyze for (1kHz).

Have fun, Hannes
  Reply With Quote

Reply


Blameless THDHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Blameless Amp layout Ipanema Solid State 84 15th December 2012 12:50 AM
A tubular 'Blameless' GK Solid State 46 26th January 2010 12:53 AM
Please, help me with Self Blameless Ric_rock Solid State 45 13th January 2010 05:03 PM
Transistors for Blameless tommytube Solid State 2 3rd May 2007 09:10 AM


New To Site? Need Help?

All times are GMT. The time now is 04:20 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki