Lift off - 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 June 2004, 08:09 AM   #1
diyAudio Member
 
Join Date: Jun 2004
Location: Antwerp
Default Lift off

So I started on designing my first amp. Not being someone that believes in half measures, I decided to look into power supply design for starters.
I've decided that I want to build a class A amp, delivering 100W into 8 Oms, that's absolutely stable to 1 Ohm, doubling power as impedance goes doewn. So it needs to deliver 800 W way down there.
I've already run into the first snag, heat dissipation. at 800W, I would need to dissipate 1600W. At 100W this is a more manageble 200W, but still, no mean feat ! I'm not in favour of using fans, and using liquid nitrogen might prove a tad cumbersome.
Question : how do the big boys solve this ? I have read about 'anticipator' style designs, that adapt bias according to input signal. Has anyone already done work on this, are there diy solutions available that sort this out.
Input ! More input !!!

Thanks in advance,

Peter R.
  Reply With Quote
Old 12th June 2004, 06:12 PM   #2
sreten is offline sreten  United Kingdom
diyAudio Member
 
Join Date: Nov 2003
Location: Brighton UK
No sensible design is still class A into 1R loads.

Your best bet is to design for say nominally 100W class A
into say a 6R load and then let it enter class B for lower
impedances.

This is ~ 3.2A standing current and ~ +/- 45V rails.

You''ll probably need 6 or 8 devices per channel for 1R loads,
and of course a whopping transformer and lots of PS capacitance.

As you can see dissapation will be ~ 300W per channel,
so lots of heatsinking also.

Personally I'd go for optimally biased class aB. With 8 devices
per channel and 0.1R emitter resistors an EF stage would
have around 800mA of standing current, this is enough to
almost say the first 5 watts are class A.

sreten.
  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
tone arm lift woodturner-fran Analogue Source 33 30th March 2010 06:59 AM
Motorized projector lift (scissor lift?) JRace Everything Else 5 7th January 2008 03:11 AM
Best way to lift copper off PCB? Zero Cool Everything Else 4 19th December 2006 04:31 PM
how do I lift/not lift earth frank2395 Pass Labs 30 31st May 2005 07:38 AM
Arm lift and other accessories AuroraB Analogue Source 1 19th August 2003 11:55 AM


New To Site? Need Help?

All times are GMT. The time now is 04:27 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