high voltage fets - 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 23rd December 2003, 03:32 AM   #1
diyAudio Member
 
Join Date: May 2003
Location: illinois
Default high voltage fets

i was wanting to make a decently powerfull amp
for home stereo subwoofer use

but i was wondering what are some good high voltage fets
i wanted to go with somewhere around 100v rails
so it would take minimal amperage draw


what would do the job i need nicely

oh btw im thinking about 500rmsx1 @ 8 ohm
  Reply With Quote
Old 23rd December 2003, 08:53 AM   #2
diyAudio Member
 
Join Date: Nov 2001
Location: Harlowton, MT, USA
First of all
Quote:
100v rails so it would take minimal amperage draw
That won't really make any difference on how much current you draw from the line, only what is going through your secondary in the PSU and the amp, no improvement at all here.

If you really do want 100V rails, you will need something at least 200V in theory, which really isn't that high for many FETs. In fact, you could probably get away with using MJ15003/MJ15004 BJTs if you were so inclined. IRFP240/IRFP9240 should work so long as you don't go much over 100V on your rails, though I would feel safer with 250V devices. I do not know of any other or better large FETs over 200V (couldn't find on IRF's site), but either IRF will have something or someone else here will know the perfect ones.

Check out Anthony Holton's MOSFET amp designs, I think they are just what you're after. http://www.aussieamplifiers.com/

500W into 8ohms? May I ask what speaker setup you will be using?

Good luck, sounds almost like something I wanted to do back in the day.

Chris
__________________
- "With power amplifiers, negative feedback is a good thing, and positive feedback can induce destructive oscillation, but with people, positive feedback is a good thing, and negative feedback can induce destructive oscillation"
  Reply With Quote
Old 23rd December 2003, 12:13 PM   #3
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Internationall Rectifier has a parametric search engine http://ec.irf.com/v6/en/US/adirect/i...etric%20Search
-- why not use it?
  Reply With Quote
Old 23rd December 2003, 12:59 PM   #4
Account Disabled
 
Join Date: Apr 2003
Location: US
fairchild has a lot of 500-600v power mosfets. However, it is hard / harder to find anyone carrying them.
  Reply With Quote
Old 23rd December 2003, 01:27 PM   #5
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Quote:
Originally posted by millwood
fairchild has a lot of 500-600v power mosfets. However, it is hard / harder to find anyone carrying them.
try Allied Electronics, Digikey, Newark Electronics, Future Active and Mouser -- they all carry the high voltage devices.
  Reply With Quote
Old 25th December 2003, 02:28 AM   #6
diyAudio Member
 
Join Date: May 2003
Location: illinois
i was thinking two adire tempests

or maybe even two elemental designs 12kx

need some massive thump for the home theator

and have been trying to stay back and read and learn from you guys

i think im starting to figure it out
so i was going to try to jump head in and build something

thanx for all the help guyz
great community

  Reply With Quote
Old 25th December 2003, 03:21 AM   #7
FACTOR is offline FACTOR  India
Banned
 
Join Date: Nov 2003
Location: Nawanshahar-Punjab-India
Default highpower mains operated amps

I have designed several mains operated amps using IRFP460N Mosfets rated at 500V 20A 280W which doesn't use mains transformer, to use at 100volts supply range IRFP250N, IRFP260N,IRFP264N are well substitutes
  Reply With Quote
Old 25th December 2003, 03:33 AM   #8
diyAudio Member
 
Join Date: May 2003
Location: illinois
Default Re: highpower mains operated amps

Quote:
Originally posted by FACTOR
I have designed several mains operated amps using IRFP460N Mosfets rated at 500V 20A 280W which doesn't use mains transformer, to use at 100volts supply range IRFP250N, IRFP260N,IRFP264N are well substitutes

you my friend know exactly what i was looking for
transformerless
unregulated power supply

do you have any schematics i might take a look @?
  Reply With Quote
Old 25th December 2003, 06:25 AM   #9
diyAudio Member
 
Join Date: Nov 2001
Location: Harlowton, MT, USA
I believe Mr. Pass had done something like that. A very interesting concept, and really the thing to do it seems if you want a lot of power into high ohm loads and can't afford a massive transformer. A few years ago here, I wanted to do it (off a 120/240V CT circuit), and everyone was highly opposed the idea, because there is no mains isolation, little protection against noise and spikes, and... what speakers would you drive with such a thing? If none of this bothers you though, somewhere exists a schematic of Anthony Holton's 800W amplifier, IIRC. His online manuals section is down right now though. Or maybe it's this one I'm thinking of. http://www.aussieamplifiers.com/sym-sch.htm Either way, his larger version runs with 110V rails, so, that's fairly close, closest I've seen.

This won't be just a throw-together type thing if you end up having to do much designing on your own. There are few amps that operate with this high of rail voltages, and you will need a very high slew rate if you plan on getting good performance through the entire spectrum. This can compromise stability and your circuit could go into oscillation if you push it too much.
__________________
- "With power amplifiers, negative feedback is a good thing, and positive feedback can induce destructive oscillation, but with people, positive feedback is a good thing, and negative feedback can induce destructive oscillation"
  Reply With Quote
Old 25th December 2003, 08:05 AM   #10
FACTOR is offline FACTOR  India
Banned
 
Join Date: Nov 2003
Location: Nawanshahar-Punjab-India
Thumbs up TYPE OF AMP PA or SUBAMP


Hello To every body Thanx for the interest in my direct mains operated 240VAC amps
My designs are basically for P.A amps and Subwoofer amps
In PA amps i use input isolation transformer and output isolation transformer and the output devices which i use are N-channel mosfets from IRF i.e. IRFP460N for power output of 2KW To 5KW which are operated at 340VDC
In my Subwoofer amps I use input isolation transformer, 600V 75A 625W IGBTs with no output isolation transformer and output ranges from 2KW To 5KW because my amplifier is fitted in the subwoofer enclosure therefore the output is live and is safe because it is directly connected to low frequency drivers inthe enclosure thereby preventing any shock hazard
So tell me what type of amp are u interested in, so i can give u my schematics in order to help u.
  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
1kw+ SMPS...blowing FETS at full voltage kvasefi Power Supplies 21 1st February 2010 11:17 PM
What about FETs for Cellular Base Stations in Audio Cascode Voltage Gain Stage (line tiefbassuebertr Solid State 8 23rd August 2009 02:53 AM
Wanted - High Power, High Voltage, Audio Frequency Transformer Manual. kimbal Tubes / Valves 4 11th May 2009 08:05 PM
Fets for high bias Zen4 Buhl Pass Labs 0 9th December 2002 10:39 AM


New To Site? Need Help?

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