Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Chip Amps Amplifiers based on integrated circuits

my first amp based on lme49830
my first amp based on lme49830
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 27th September 2012, 02:37 PM   #1
snakebite is offline snakebite  Israel
diyAudio Member
 
Join Date: Aug 2011
Default my first amp based on lme49830

hello,

this is my first post here so i introduce myself. i'm study EE in uni. i'm now on my last year and maybe this will be my graduate project!
before i'm starting my project, i wanted to ask a question about the transformer.
i know it's better to use a toroide type transformer because of the low noise high effictioncy and the small profile but i'd like to know which one i need.

i'm planning to build 100w x 5 amp @ 8ohm . so based on ohm's power law:
P=I * V = V^2 / R = I^2 * R
so if i need P=100W and R=8ohm
V=28.28VDC (after the rectifing , smothing and regulation)
A= 3.5A.
is it correct? or i need a safe margine?

based on this i need a transformer rated on about 500VA (or more??) ??

thanks
Ido
  Reply With Quote
Old 27th September 2012, 03:26 PM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
if you build one channel (two channels won't get you any higher grade) then expect a 100VA to 200VA transformer to successfully power a 100W amplifier.

If you want that 100W into 8ohms speaker the use a 35+35Vac transformer to get the PSU voltage right.

But here's me giving you the answers.
__________________
regards Andrew T.
  Reply With Quote
Old 28th September 2012, 12:28 AM   #3
snakebite is offline snakebite  Israel
diyAudio Member
 
Join Date: Aug 2011
so if i want 500W amp i need 500VA transformer ? what about the current calc. that i made, is it correct? or do i need to take higher current rating for spikes or whatever (i calculated about 3.5A per channel so if i take 4A per channel is it enough or i need more?)
  Reply With Quote
Old 28th September 2012, 12:43 AM   #4
TonyTecson is offline TonyTecson  Philippines
diyAudio Moderator
 
TonyTecson's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
my first amp based on lme49830
^if you are just playing music, then that should do.....
__________________
planet10 needs your help: Let's help Ruth and Dave...http://www.diyaudio.com/forums/plane...ml#post5010547[B
  Reply With Quote
Old 28th September 2012, 12:54 AM   #5
snakebite is offline snakebite  Israel
diyAudio Member
 
Join Date: Aug 2011
what you mean by "just playing music" and if i watch DIVX movies it won't be enough?? can you explain yourself...?
  Reply With Quote
Old 28th September 2012, 11:57 AM   #6
Boscoe is offline Boscoe  United Kingdom
diyAudio Member
 
Join Date: Feb 2010
Location: England
How do you not know this stuff if your at uni? It's very basic, just do a little reading. If you knew basically how an amplifier works its very easy to make a psu for it.
__________________
Audio projects and more: gswdh.co.uk
  Reply With Quote
Old 28th September 2012, 11:57 AM   #7
Boscoe is offline Boscoe  United Kingdom
diyAudio Member
 
Join Date: Feb 2010
Location: England
Quote:
Originally Posted by snakebite View Post
what you mean by "just playing music" and if i watch DIVX movies it won't be enough?? can you explain yourself...?
Doesn't matter.
__________________
Audio projects and more: gswdh.co.uk
  Reply With Quote
Old 28th September 2012, 03:52 PM   #8
Headbanger is offline Headbanger  Austria
diyAudio Member
 
Join Date: Aug 2012
Location: Völkermarkt
I wonder if anyone have used LME49830 at unity gain, inverting, compensated.
  Reply With Quote
Old 28th September 2012, 03:53 PM   #9
sreten is offline sreten  United Kingdom
R.I.P.
 
Join Date: Nov 2003
Location: Brighton UK
Hi,

Unfortunately EE courses don't teach most of the basics of sensible
cost effective analogue audio design, or teach you any common
sense regarding properly selecting and properly dimensioning
components and hardware for higher power audio amplifiers,
and that ends up being a matter of opinion as well as design.

The decision process for a power supply is far more complicated
than outlined in the initial post but with experience designers settle
on "rules of thumb" that simply won't do in a project write-up.

Different designers can have different "rules of thumb". Different
rules can apply if cost is the major issue compared to performance
(at higher cost) being the major issue. There are no simple answers.

Good design is balancing these factors.

rgds, sreten.

Generally I don't like Mosfet outputs with simple supplies
as you lose too much voltage swing at the output for me.
  Reply With Quote
Old 28th September 2012, 04:03 PM   #10
hochopeper is offline hochopeper  Australia
diyAudio Member
 
Join Date: Feb 2009
Location: Brisbane, Australia
Quote:
Originally Posted by Headbanger View Post
I wonder if anyone have used LME49830 at unity gain, inverting, compensated.
From memory LME49830 stipulates min gain of 26dB for stability.
  Reply With Quote

Reply


my first amp based on lme49830Hide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
"The Wire AMP" Class A/AB Power Amplifier based on the LME49830 with Lateral Mosfets opc Solid State 2614 24th July 2017 04:37 AM
Looking for a PCB or layout for an LME49830 amp pebo Chip Amps 13 3rd February 2017 07:53 PM
Lme49830 nickarsow Chip Amps 98 16th January 2016 01:31 AM
X-Amp (LME49830 + Exicon Lateral Mosfets) danfo098 Chip Amps 28 14th October 2013 05:05 AM
6 channel LME49830 power amp cuibono Chip Amps 135 7th August 2011 01:52 AM


New To Site? Need Help?

All times are GMT. The time now is 07:57 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki