here is the schematic
wat type of amplifier is this IC??

Attached Images

80_watt.jpg (175.2 KB, 937 views)

 

there is nothing posted :?: :?:

 

That audio amp has the lowest noise and distortion that I have ever heard. (Seen?)
As audiophiles say, its sound is very transparent! :lol:

Even if we could see its schematic, what is an amplifier's type?
1) Cheap or expensive?
2) Lousy or excellent?
3) Tooobes (valves) or solid-state?

We will just wait for its schematic to be attached then see that it is a Cmos inverter self-biased as a linear amplifier or sumpthin'

__________________
Uncle $crooge

 

i found its data sheet
it is a Qusai AB type amplifier

will this circuit work?
i'll start working on it from tomorrow

can u explain its working a bit?
the 2 capacitors in parallel..what is it called?

 

As are the vast majority of transistor audio power amplifiers. The circuit you posted actually uses two amplifiers in a bridged configuration, to give twice the power to twice the impedance of a single amplifier.

I don't see why not?.

It's called two capacitors in parallel! :lol:

It's done because the decoupling effect of the large electrolytics will be less at higher frequencies, so adding a small non-electrolytic capacitor in parallel can improve decoupling at high frequencies.

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The LM3875 is an excellent audio amp IC. Look at its product folder:
http://www.national.com/pf/LM/LM3875.html
In the folder is a link to its datasheet that you should have. It has details about heatsinks and stuff. :lol:

__________________
Uncle $crooge

 

thnx guru

 

dual power supply
how will i check my project at home?
i hav a dual power supply in univesity...
not at home....
ne shortcuts?
or how do i design a +-25 volt power supply?

 

Why use shortcuts when building an excellent power amplifier?
If its supply was a single polarity the the amp would need the problems of a huge output coupling capacitor.

Wait a minute! This is a bridged amp. It will work fine without an output coupling cap if you properly bias the inputs so it can use a single +50V supply. It might have a pretty big "bang" when it is turned on or off unless you plan to have its input coupling cap charge and discharge slowly.

I started reading all the artilces and comments about these "Gainclone" amps on the web. Some are hillarious.

Attached Images

80_watt.png (61.1 KB, 857 views)

__________________
Uncle $crooge

 

The 2nd amp amplifies the distortion of the 1st amp, so maybe the 2nd amp should be inverting and get its input directly from the input. :lol:

__________________
Uncle $crooge

 

Why is the very bottom resistor 24K?.

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Hee, hee. :lol: What 24k resistor? :lol:
The original was wrong.

__________________
Uncle $crooge

 

ok..i am making a dual power supply for it too
it'll earn me more marks

i found a schematic for it

if tht output is less than 25 say...23 or 22..will by power amp work?
or should i make a supply with a wider range? say till + - 35?
how can this one be improvised?
using a higer rating transformer?
ne other changes?

Attached Images

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You only need a very basic supply, just a center tapped transformer, something like 18-0-18 (bit too high) or 15-0-15 (bit too low), a bridge rectifer, and two large electrolytics.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

check the schematic i attached...is it fine???