mosfet output conversion - 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 12th October 2007, 02:45 AM   #1
diyAudio Member
 
Join Date: Oct 2005
Default mosfet output conversion

can somebody help me converting a match pair mosfet output to a quasi design output or two npn output like 2sk1058 and 2sj201 my reason is i have lots of npn mosfet and i like to use it
Attached Images
File Type: gif amplisimple.gif (6.7 KB, 455 views)
  Reply With Quote
Old 12th October 2007, 09:22 AM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
find a schematic that gives what you need.
The design shown is using the VAS to drive the FETs directly. I do not like this arrangement since it forces the adoption of big medium power transistors for Q3 to Q7 inclusive. Then these load up the LTP, also not good.
Get a better schematic.

Have a look at Quasi's designs. There are three or more threads covering all the detail of the design and build with a wealth of buider input and a superb web site put up by Quasi.

You did search "quasi", you cannot post without saying "yes".
__________________
regards Andrew T.
  Reply With Quote
Old 12th October 2007, 12:47 PM   #3
diyAudio Member
 
Join Date: Oct 2005
Default mosfet output

andrewt
thanks,for long i've been searching for quasi design,any comment on quasi's n-mos amp,i just wan't to use my n-channel fets,from surplus shop
  Reply With Quote
Old 12th October 2007, 12:55 PM   #4
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
What more comments do you want? He recommended the design to you. Have a look on the threads by quasi, they are full of information.

What MOSFETs have you got?
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 12th October 2007, 01:17 PM   #5
diyAudio Member
 
Join Date: Sep 2007
Default quasi comp

hello,

I have tried this output stage, good to me

http://perso.orange.fr/francis.audio2/C07_FB1a.gif

JMB
  Reply With Quote
Old 12th October 2007, 01:52 PM   #6
ilimzn is offline ilimzn  Croatia
diyAudio Member
 
Join Date: Feb 2005
Location: Zagreb
Default Re: quasi comp

Quote:
Originally posted by jmbaudoin
hello,

I have tried this output stage, good to me

http://perso.orange.fr/francis.audio2/C07_FB1a.gif

JMB
Shouldn't that have at least some sort of thermal sompensation?
  Reply With Quote
Old 12th October 2007, 02:08 PM   #7
Did it Himself
diyAudio Member
 
richie00boy's Avatar
 
Join Date: Nov 2003
Location: Gloucestershire, England, UK
It uses lateral devices, so no need.
__________________
www.readresearch.co.uk my website for UK diy audio people - designs, PCBs, kits and more.
  Reply With Quote
Old 12th October 2007, 04:00 PM   #8
ilimzn is offline ilimzn  Croatia
diyAudio Member
 
Join Date: Feb 2005
Location: Zagreb
Quote:
Originally posted by richie00boy
It uses lateral devices, so no need.
Really? Te top is a 'darlington' with a BJT in front so at best it will have zero Tc at well over 200mA, and the bottom is a CFP with BJT in front which has the TC of the BJT transistor. Have you simulated at different temperatures?
  Reply With Quote
Old 12th October 2007, 04:30 PM   #9
diyAudio Member
 
Join Date: Oct 2007
Default Re: Re: quasi comp

Quote:
Originally posted by ilimzn


Shouldn't that have at least some sort of thermal sompensation?

I've read power MOSFETs had negative thermal resistance... so, when, temperature clims up, its conductance goes down, or something like that, but I think that happens with audio output mosfets, the lateral ones, no t teh vertical, made for switching purpose, although you can use it on audio! They're cheaper too!

Thanks to Flavio Dellepiane, visit his site, please.

www.redcircuits.com
  Reply With Quote
Old 12th October 2007, 04:30 PM   #10
diyAudio Member
 
Join Date: Sep 2007
In my experience there is no need for thermal compensation with mos-fet bias between 0.3 to 0.7 Amps , thus motorola drivers had their own heather, and Mos where BUZ sort. used with 0.3 C /W heather per chanel.
  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
mosfet i/v conversion from D1 with pcm1704 schiller Digital Line Level 4 15th April 2009 09:26 AM
minus 25 on output mosfet amp Jan Deckers Solid State 3 12th April 2009 05:14 PM
Do mosfet output devices age? Geesixty Solid State 10 19th April 2006 02:14 PM
Power amp output - BJT or MosFET? Bill Fitzpatrick Solid State 20 25th April 2004 03:58 AM
output Mosfet for Aleph2 Cephas Pass Labs 14 17th April 2002 03:46 PM


New To Site? Need Help?

All times are GMT. The time now is 11:58 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