hi!
I know i'v seen a post where a guy had a simular problem some time ago, but i cant find it, so i'm making a new one.
as the topic says i'v been making a lm3886 amp and finally got it finnished.
as i try it out it blows the membrane of my speaker almost up to the roof! (ok, now i'm overesaturating)
i measure +25V of the board and when the trusty old test speaker is connected the membrane was pushed as far as it would go and i head hum and hissing.
the thing is made with kostasthegrate's pcb, etched it myself.
there is no apparrent short circuts anywhere eiter.
i have absolutly no clue as to what could be wrong with it, every thing should be correct!
the trafo is a 160w transductor 2*17.5V
i'l post some pics of the amp and the scematics if its needed in finding the problem.
thanks a lot!
regards
marius
I know i'v seen a post where a guy had a simular problem some time ago, but i cant find it, so i'm making a new one.
as the topic says i'v been making a lm3886 amp and finally got it finnished.
as i try it out it blows the membrane of my speaker almost up to the roof! (ok, now i'm overesaturating)
i measure +25V of the board and when the trusty old test speaker is connected the membrane was pushed as far as it would go and i head hum and hissing.
the thing is made with kostasthegrate's pcb, etched it myself.
there is no apparrent short circuts anywhere eiter.
i have absolutly no clue as to what could be wrong with it, every thing should be correct!
the trafo is a 160w transductor 2*17.5V
i'l post some pics of the amp and the scematics if its needed in finding the problem.
thanks a lot!
regards
marius
demogorgon said:well, pictures was requested.
hope this helps..
regards
marius
"Not Found
The requested URL /forums/www.home.no/demogorgon/scematics.JPG was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request."
well, then let's do it the hard way:
you know the filenames from above, sp just hit the link without the picture name.
www.home.no/demogorgon/
it's working for me.
edit: i dont have an index file yet, so you'l se the index.
just find the files
above.JPG
under.JPG
scematichs.JPG (misspelled)
you know the filenames from above, sp just hit the link without the picture name.
www.home.no/demogorgon/
it's working for me.
edit: i dont have an index file yet, so you'l se the index.
just find the files
above.JPG
under.JPG
scematichs.JPG (misspelled)
the schematic found here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=41373&perpage=10&pagenumber=4
i did something stupid i must admit.
I etched, drilled and solderd, but never questioned or read or studied.
so i really dont know anything of what u are talking about..
well, maby its not too late. i'l sit down with my adobe and lm3886 spec sheet i guess.
i did something stupid i must admit.
I etched, drilled and solderd, but never questioned or read or studied.
so i really dont know anything of what u are talking about..
well, maby its not too late. i'l sit down with my adobe and lm3886 spec sheet i guess.
this chip is kind of an op-amp so the 220k resistor between the input and output somehow diktate the mount of gain in the chip? or something like that.. it's getting kind of late here in this part of europe 
well, its a no big deal, i haven't used the pcd because i didn't have a small enough drill, so all i have to do is solder the resistor to a different pin..
well, thanks man!
if it works now, i actually have a working gainclone..
well, its a no big deal, i haven't used the pcd because i didn't have a small enough drill, so all i have to do is solder the resistor to a different pin..
well, thanks man!
if it works now, i actually have a working gainclone..
demogorgon said:this chip is kind of an op-amp so the 220k resistor between the input and output somehow diktate the mount of gain in the chip? or something like that.. it's getting kind of late here in this part of europe
You've got there.
demogorgon said:
Yuuuuuuuuuuuuuuuuuupiiiiiiiiiiiiii!!!
Congratulations!
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