200 Watt Lateral Mosfet Amplifier and irfp240/9240 - 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 14th April 2003, 05:01 PM   #1
tino96 is offline tino96  Italy
diyAudio Member
 
Join Date: Mar 2003
Location: .
Default 200 Watt Lateral Mosfet Amplifier and irfp240/9240

Is possible to change in the 200 Watt Lateral Mosfet Amplifier the output device 2sj 352 and 2sk2221 with irfp240/9240?

If yes, how to do?
p.s. excuse my poor english
bye
  Reply With Quote
Old 14th April 2003, 05:24 PM   #2
JBL is offline JBL  Canada
diyAudio Member
 
JBL's Avatar
 
Join Date: Aug 2001
Location: Canada, N.-B.
Send a message via ICQ to JBL
Nop.

The amp will probably explode or somthing similar.
__________________
Jonathan Blanchard (J.Bl.)
---Nothing is impossible---
  Reply With Quote
Old 14th April 2003, 05:28 PM   #3
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Depends on the amp. The IR parts will have higher transconductance (which is why I prefer them) and different Vgs values. Without a doubt you will have to rebias the circuit for the new Vgs figure.
  Reply With Quote
Old 14th April 2003, 05:40 PM   #4
tino96 is offline tino96  Italy
diyAudio Member
 
Join Date: Mar 2003
Location: .
the amp is the symmetrical amplifier (designed by Anthony Holton) http://www.aussieamplifiers.com/symmetric.htm
it's possible?
  Reply With Quote
Old 14th April 2003, 06:45 PM   #5
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
I couldn't find any datasheets for IRF240/9240 (searching the
web suggested they are obsolete) but the general answer
would be no, you can probably not use them. Lateral MOSFETs
start to have a negative temp. coefficient already at rather
small Id, so usually no temp. compensation of the bias is
necessary, and indeed Holton's amp follows this practice.
Although I don't know about the IRF240/9240, most, if not
all, non-lateral MOSFETs have a positive temp. coefficient up
to quite high values of Id, several Ampéres, so I would think
they need temp. compensation of the bias.

Perhaps Nelson, or someone else, can give a good reason why
it might work anyway, but the safe general recommendation
would be not to try it.
  Reply With Quote
Old 14th April 2003, 07:23 PM   #6
diyAudio Member
 
Andypairo's Avatar
 
Join Date: Sep 2002
Location: near Milano , Italy
In the description of the symmetric amplifier is clearly stated that IRF devices are suitable; for the lateral mosfet I don't think so.

Cheers

Andrea
  Reply With Quote
Old 14th April 2003, 07:37 PM   #7
diyAudio Member
 
megajocke's Avatar
 
Join Date: Jan 2003
I found a datasheet for IRF240:
http://circuit.codns.com/data/DataSheet/FET/IRF240.PDF

Hehe... the temerature coefficient doesn't become negative before 11 amps...

tino96: Is it the Symmetric amplifier or the Lateral amplifier you are talking about?

The symmetric amplifier uses a Vbe multiplier, and maybe mounting that together with the transistors would be enough to compensate it... but the other one uses just a pot, and that is probably bad. Another thing is the gate-source voltage of the lateral mosfets are much lower. around 0.5V at 100ma for the lateral mosfets and around 4V for the other one...
  Reply With Quote
Old 14th April 2003, 09:00 PM   #8
HighTec is offline HighTec  Croatia
diyAudio Member
 
HighTec's Avatar
 
Join Date: Mar 2003
Location: Sibenik, Croatia
Exclamation IRFP240???

Hi guys.

We are talking about IRFP240/IRFP9240!They are not similar with IRF240!And they can't be a replacement for the lateral mosfets.
Regards.
  Reply With Quote
Old 14th April 2003, 10:28 PM   #9
diyAudio Member
 
megajocke's Avatar
 
Join Date: Jan 2003
Ooops I read the number Christer wrote and didn't check what the OP had written.

IRFP240:
http://www.fairchildsemi.com/ds/IR/IRFP240.pdf
  Reply With Quote
Old 14th April 2003, 10:55 PM   #10
diyAudio Member
 
Join Date: Feb 2001
Location: Mars
Build the holton AV800 instead..
  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



New To Site? Need Help?

All times are GMT. The time now is 12:12 AM.


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