my new ampli mosfet - 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 5th August 2008, 12:53 PM   #1
xcicc is offline xcicc  Italy
diyAudio Member
 
xcicc's Avatar
 
Join Date: Aug 2008
Default my new ampli mosfet

Hi, I try to make this ampli any suggestion?
regard
A.
Attached Images
File Type: gif pm100im2.gif (34.9 KB, 882 views)
  Reply With Quote
Old 5th August 2008, 01:25 PM   #2
diyAudio Member
 
darkfenriz's Avatar
 
Join Date: Jun 2004
Location: Warsaw
Check out current sources and polarity of P-fet.
  Reply With Quote
Old 5th August 2008, 03:07 PM   #3
xcicc is offline xcicc  Italy
diyAudio Member
 
xcicc's Avatar
 
Join Date: Aug 2008
Quote:
Originally posted by darkfenriz
Check out current sources and polarity of P-fet.
Hi made some change the polarity on P-fet and I add the voltage...
A.
Attached Images
File Type: jpg pm100im2.jpg (82.8 KB, 675 views)
  Reply With Quote
Old 5th August 2008, 03:35 PM   #4
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
I think the output bias scheme will give you problems due to wide tolerance of Vgs. Also I think there is massively insufficient drive to the output MOSFETs.
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 5th August 2008, 03:43 PM   #5
fab is online now fab  Canada
diyAudio Member
 
fab's Avatar
 
Join Date: Mar 2004
Location: Canada
Default triac?

Hi,

Is there a triac between the amp output and input of drive of mosfet2? if so, what is its purpose. Is it a protection and how is it suppose to work?

Thanks
  Reply With Quote
Old 5th August 2008, 08:30 PM   #6
xcicc is offline xcicc  Italy
diyAudio Member
 
xcicc's Avatar
 
Join Date: Aug 2008
Default Re: triac?

Quote:
Originally posted by fab
Hi,

Is there a triac between the amp output and input of drive of mosfet2? if so, what is its purpose. Is it a protection and how is it suppose to work?

Thanks

Hi, yes the purpose of this triac is for short circuit protection.
why? is useless??
A.
  Reply With Quote
Old 5th August 2008, 08:44 PM   #7
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
You are still forgetting about powering of left upper current sources.
__________________
"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 6th August 2008, 02:11 AM   #8
fab is online now fab  Canada
diyAudio Member
 
fab's Avatar
 
Join Date: Mar 2004
Location: Canada
Quote:
Originally posted by Wavebourn
You are still forgetting about powering of left upper current sources.
He's right. At least a resistor should be put from the diodes-transistors base connection point to either ground or negative power rail.
  Reply With Quote
Old 6th August 2008, 05:36 AM   #9
xcicc is offline xcicc  Italy
diyAudio Member
 
xcicc's Avatar
 
Join Date: Aug 2008
Quote:
Originally posted by fab


He's right. At least a resistor should be put from the diodes-transistors base connection point to either ground or negative power rail.
Hi, you mind this? I made some correction I hope is right...
Attached Images
File Type: jpg pm100im2.jpg (71.0 KB, 522 views)
  Reply With Quote
Old 6th August 2008, 05:56 AM   #10
lineup is offline lineup  Sweden
diyAudio Member
 
lineup's Avatar
 
Join Date: Dec 2005
Location: the north
Latest attachment.
http://www.diyaudio.com/forums/attac...amp=1218000976

It might work.
But personally I woul use a little bit more current to bias the GATES of IRFP140/9140

28Volt/100kohm ~ 0.3 mA
Make those 100 kohm resistors ~27 kohm .. or even 10 kohm
Would give: ~ 1 - 3 mA

Also I would connect those bias resistors ( 100kohm / 27 kohm )
BEFORE those gate stoppers ( 47 Ohm resistors ).


If you change from 100 kohm .. to 27 kohm,

then you should make those 47 kohm (in parallel with 4.7uF) smaller, too.
Maybe like 4k7.
And those two (now 47 kohm) should be connected to GROUND.
To try and keep, hold, the output MOSFETs at zero DC Offset.
The point between those two resistors, I mean, should be connected to GND.
__________________
lineup
  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
use a PA ampli for sub cld1354 Multi-Way 29 29th June 2009 09:39 AM
ampli mosfet irf 540 + irf9540 xcicc Solid State 24 20th March 2009 12:10 AM
ampli mosfet with irf530/9530 ciccio9000 Solid State 17 10th June 2007 10:41 PM
My Ampli Pollix Solid State 9 9th February 2004 09:50 AM


New To Site? Need Help?

All times are GMT. The time now is 10:03 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