what a LME49811 class A amplifier with 50watts into 4 ohms or more - 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 15th September 2012, 07:52 PM   #1
diyAudio Member
 
Join Date: Aug 2012
Default what a LME49811 class A amplifier with 50watts into 4 ohms or more

I want to build a Class A amplifier with LME49811 to about 50watts RMS into 4 ohms.

If I can get 100 into 4 it would still be great...

I came to know there are many problem matching the transistors and its really tough to do so since one will waste 50 transistors to match two of them.

Is matching is only about hfe or anything else like i dont know its VFD or something i dont remember.

which transistors to use?
how many to use? to get 50rms into 4 ohms
how much should be the bias current? how is this calculated?
can I buy a LME49810 and plug the LME49811? since both have similar characteristics?

is the quality of the amp good? did anybody try LME49811?
  Reply With Quote
Old 15th September 2012, 08:35 PM   #2
diyAudio Member
 
Join Date: Feb 2009
50W classA in 4ohm? that is ALOT. that demands 2.6A bias
and with about +/-25V you are looking at 260W dissipation pr ch at idle.
in best case.
  Reply With Quote
Old 15th September 2012, 08:37 PM   #3
diyAudio Member
 
Join Date: Aug 2012
fine no issues...
  Reply With Quote
Old 15th September 2012, 09:20 PM   #4
diyAudio Member
 
Join Date: Apr 2010
Location: Coffs Harbour, on the east coast
You seem to need a complete course in audio electronics design. Even that will not be enough to answer so many questions that, when you use terms like "sound quality" will be subjective opinions, so you will not get agreement because we all have different ideas, purposes and musical tastes in mind when we make suggestions.

A group of people will agree a view about perceived sound through peer pressure, their field of employment or the education they received but you won't get such broad questions satisfactorily resolved and answered here. Discovering how and why designs succeed or fail to meet realistic aims of what audio should do is what you should be about. Otherwise, it can take forever just discussing the nebulous possibilities of designs so to get anywhere, simply dive in and experiment with simple, popular ideas first, learn some, get them to work and ask how to progress from there.

You can build a great, high quality amplifier without ever considering transistor matching for those discrete designs that might need it. Manufacturers usually don't either. Not only can you simplify the front end of an amplifier with chips like LM49810 etc. but you can even build a complete Chip-amp in an afternoon for small bucks, that easily meets your 50W/4R power requirements and reallydoes sound good. Many highly acclaimed commercial amps and many powered monitors use nothing more inside the box than an LM3886 so if you have not tried a properly implemented type (visit and read some of the Chip-amp forum) then don't hesitate to get involved there first. Chip-amps cut all the hassles and ulcering over what bits and and parts brands will impress the snobs, gurus and satisfy the usual know-nuthin' opinions that surround electronic components. The less parts used, the less nonsense.

Before even dreaming about 50W in class A, read an audio electronics text first and try building a chip-amp soon.
__________________
regards
  Reply With Quote
Old 15th September 2012, 09:41 PM   #5
diyAudio Member
 
Join Date: Feb 2009
Quote:
Originally Posted by AudioSan View Post
50W classA in 4ohm? that is ALOT. that demands 2.6A bias
and with about +/-25V you are looking at 260W dissipation pr ch at idle.
in best case.
EDIT: 130W
  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
Amplifier 4/8 ohms Selector viki1967 Solid State 4 28th July 2012 03:44 AM
1500 watts ab class 2 ohms andrewlebon Solid State 51 4th June 2012 09:50 PM
15 ohms (12 on ohmmeter) with 24 ohms resistor in parallel to bring to 8 ohms McIntosh Man Multi-Way 29 11th June 2010 05:36 PM
Class A with LME49811... Dxvideo Chip Amps 22 2nd November 2009 01:11 PM
200W in 8 Ohms Class D amp wanted Session Class D 5 8th October 2009 07:08 PM


New To Site? Need Help?

All times are GMT. The time now is 12:00 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