Clipping Behaviour - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 29th January 2013, 09:29 AM   #1
2KW is offline 2KW  Australia
diyAudio Member
 
Join Date: Jan 2007
Default Clipping Behaviour

Hi guys,

On a power amp I'm designing I have a strange clipping behaviour that does'nt show up on simulation. In the negative half cycle the transistor seems to 'stick' on, followed by a turning off spike. This happens at higher frequencies, and gets worse as frequency increases. I was wondering if someone could point me in the right direction as to what could be causing it. I have attached some oscilloscope pics and a pic of the circuit to help clarify what I mean. The fuzziness in the second pic ( clipping with no spike ) is due to the glass on the CRO.

Thanks.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 29th January 2013, 09:58 AM   #2
diyAudio Member
 
Join Date: Jun 2005
Location: Zürich
Perhaps Q26 saturating? Simplest fix would be to put another diode in series with D9.

Samuel
  Reply With Quote
Old 29th January 2013, 04:54 PM   #3
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
you could post the asc - I put the nonstandard lib part's model defs right in the schematic for max portability - use the spice directive tool

"wind up" and saturation can make for bad clipping recovery

output Q saturation can be improved with a Baker Clamp

may need to clamp the mirror too

and I don't think the complication/extra diode drop of the Wilson circuit is very useful with discretes - try just the 2 Q mirror

Last edited by jcx; 29th January 2013 at 05:00 PM.
  Reply With Quote
Old 29th January 2013, 05:15 PM   #4
ilimzn is offline ilimzn  Croatia
diyAudio Member
 
Join Date: Feb 2005
Location: Zagreb
Your lower half of the amp is saturating. Simulator models do not model saturation and charge storage well and in most cases at all, hence you won't see it in the simulation. So, as Bob Pease used to say, in theory there is no difference between theory and practice, but in practice there is. Welcome to the real world
  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
Recovery from clipping, soft clipping hahfran Solid State 49 23rd February 2010 01:03 AM
PTC Behaviour jayam000 Solid State 11 4th May 2009 03:35 AM
LM3886 clipping behaviour cs Chip Amps 18 18th February 2008 04:44 PM


New To Site? Need Help?

All times are GMT. The time now is 03:50 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