200W IRS2092 Amp for $20

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Thanks for the measurements. Can you please explain what the different traces are? I am trying to understand the output ripple at load. I assume one trace is amp output into 8ohms and the noisy one is the SMPS voltage at the amp input? About 2Vpp?

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Tha FLIR is a nice toy - what doe those cost?
 
So I modded the board.


Change inductor and some capacitors.


I have a problem: amp is very noisy and very loud. Also on min volume its very very loud and noisy.


Befor demounting from system it worked normal. What could be the reason?


Power supply was 30V and yet its 48V
 

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Hi hansueli,

I'd like to offer an opinion but your schematic piece in post #453 is really hard to read. Is there a possibility you could try posting it another way?

It looks like the big 6-channel board says +/-35V on those 8 pins, second from the left rear edge.(?) Wouldn't powering it with +/-48V require some redesign?

Regards,
Rick
 
Hi Rick


Thanks for your answer.


So i will repost the schematic

irs2092-1 — imgbb.com




Yes I change some caps for higher voltage.
The system works. I need to place heatsink on 12V VCC for IC power... From 48V to 12V is much more heat than from 30V to 12V.
AMD08 in schematic also got hot. Why?




I put 2.2k in the signal rail with 24k to ground and left the 10uF signal cap. But still very noisy and too loud.
 
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Much better. Thanks.

Studying it now.

One thing straight-away -- your outputs, the IRF6645's, are only rated 100V. May not be a problem right away, but that would be too close for my comfort when you have +/-48V rails. Wouldn't give even a tiny safety margin for, say, the spikes resulting from even a small amount of leakage inductance.

Can you describe the 'noise' the amp is making?

Cheers
 
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I have -5V and one 12V feeded by auxiliary output (+-15V).


And VCC regulator has some resistor and transistor for attenuate 48V to 12V for the chips.


Noise is like to high amplification and you can hear it really loud on speaker.


I don't know how to explain.




I can modd my supply for 40V if its more safe :-D
 

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