Miniature of the power amplifier LM4766 preferred - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 29th July 2011, 03:10 AM   #1
ljm_ljm is offline ljm_ljm  China
diyAudio Member
 
Join Date: Sep 2006
Default Miniature of the power amplifier LM4766 preferred

All of the power amplifier IC I like this.

Not many people like LM1875, or LM3886, more is not the TDA8920 and a digital TA2020.


Previously done much of this IC amplifiers, LM4766 is the most good. And the most simple, power can achieve +-33 V 50 W RMS 8 R. Very appropriate.

LM1875 than a much wider, close to the LM3886. And lasting appeal and the voice was very good.

DESIGN BY LJM
Attached Images
File Type: jpg 4766 SCH.jpg (228.2 KB, 771 views)
File Type: jpg IMG_2970.jpg (262.6 KB, 725 views)
File Type: jpg IMG_2971.jpg (309.8 KB, 683 views)
  Reply With Quote
Old 22nd October 2011, 08:33 PM   #2
diyAudio Member
 
Join Date: Oct 2011
I have just built this amp and hooked it to my Iphone. Serious distortion as the volume goes up past half. Any ideas
  Reply With Quote
Old 23rd October 2011, 12:26 AM   #3
! is offline !  United States
diyAudio Member
 
Join Date: Jun 2005
Location: Midwest
^ You might want to elaborate martingolder, like what supply voltage you used, whether the gain was the same (did you actually build exactly this amp or just use the same schematic with different values or ???), and whether you mean the volume on the iPhone or the amp itself (if not fixed value like it would be if only using the PCB).

Offhand guess is your gain is too high for the PSU voltage, or there was an assembly error or component flaw.

While there seems to be some English translation issues, I tend to disagree with the statement that "Not many people like LM1875, or LM3886, more is not the TDA8920 and a digital TA2020." Some like class D amps, some like A/B and higher output with LM3886, and some prefer more detail at lower output levels with LM1875.

Of course, some may like the tradeoff of increase in output power while retaining more definition that LM4766 provides. Otherwise they are very similar, the circuit you build around them can make more of a difference.
  Reply With Quote
Old 23rd October 2011, 12:40 AM   #4
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Blog Entries: 101
Send a message via MSN to abraxalito Send a message via Yahoo to abraxalito Send a message via Skype™ to abraxalito
Quote:
Originally Posted by martingolder View Post
Any ideas
If the PCB is connected strictly according to the schematic shown then the problem could be that there's no connection between input (AG) and output/power supply (ignd) grounds.
__________________
No matter if we meanwhile surrender every value for which we stand, we must strive to cajole the majority into imagining itself on our side - Everett Dean Martin
  Reply With Quote
Old 23rd October 2011, 12:53 AM   #5
diyAudio Member
 
Join Date: Oct 2011
I built exactly that amp. I am using 24VAc/1.6Amp transformer. I am using the Iphone volume control. I have tried connecting the input output grounds. I note that the amp seems to work at high volume for about 15 seconds from start and then distorts heavily. the LM4766T heats up quite a bit. I have a pentium heatsink with fan but it is not glued on yet.
  Reply With Quote
Old 23rd October 2011, 01:53 AM   #6
benb is offline benb  United States
diyAudio Member
 
Join Date: Apr 2010
LM4766 - Overture Audio Power Amplifier Series Dual 40-Watt Audio Power Amplifier with Mute
Quote:
Features SPiKe Protection
Apparently it takes the thing 15 seconds to heat up to where the "SPIKE" protection kicks in for the output power it's running at. What it's doing (the oversimplified version) is keeping the chip from destroying itself. When you properly mount it to a heat sink it won't get so hot and it won't do that.
  Reply With Quote
Old 23rd October 2011, 04:09 AM   #7
diyAudio Member
 
Join Date: Oct 2011
It's hard to imagine that the heat sink is going to clear this up. I have held it tightly to the IC but with no heat transfer gel or cement. I am thinking that for some reason it is reaching overload too quickly because of some component value being wrong and so kicking in the Spike. I will recheck all the values and mount the sink on monday when I can get the cement. Then I will post again. Thanks everyone for your comments so far. What an amazing group of people who actually know about all this stuff in technical detail.
cheers till monday or tuesday
  Reply With Quote
Old 23rd October 2011, 04:42 AM   #8
ljm_ljm is offline ljm_ljm  China
diyAudio Member
 
Join Date: Sep 2006
There are photos can see it, this is a most simple IC AMP

There are so many people in the use of it.
  Reply With Quote
Old 23rd October 2011, 04:42 AM   #9
ljm_ljm is offline ljm_ljm  China
diyAudio Member
 
Join Date: Sep 2006
THD + N at 1 kHz at continuous average output power of 2 x 30 W into 8 0.009% (typ)

Very, very low distortion.
  Reply With Quote
Old 23rd October 2011, 07:46 AM   #10
! is offline !  United States
diyAudio Member
 
Join Date: Jun 2005
Location: Midwest
^ Every semi modern chipamp has very low distortion within a certain wattage limit... given the datasheet/spec'd/ideal power for it.
  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
LM1875 miniature desktop amplifier build Dr_EM Chip Amps 5 15th June 2010 03:21 PM
Lm4766 Garyepe Solid State 2 25th August 2009 07:42 AM
Sub-Miniature Tube Amplifier Nanoo Man Tubes / Valves 2 24th January 2008 09:22 PM
Why not use LM4766?and... Richard.C Chip Amps 5 24th August 2004 08:13 PM
Lm4766 sangram Solid State 0 17th March 2003 05:44 AM


New To Site? Need Help?

All times are GMT. The time now is 11:03 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