simple but powerful

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helo i am new to diy.

i have just built an amp with opa541 the circuit is below.
thing is i am using it to power a 12ohm sub. with a power supply of 26-0-26 5amp. i have added a 22k resistance in series with input. and connected a 50ohm resistance from pin1 to ground.

should i make any modifications?

and also is there something more powerful than opa541. yet as simple as opa541.
and which can run on maybe +/- 30 or 40 volts and 2-3amps.

if know it then please post schematics and if possible pcb layout (i am an amateur)
 

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well, the lm3886 does boast a litle more power than the opa541, but it's really not a lot to speak of. 10W to the max rating i belive. not a lot when speaking of db..

since this is a subamp, i belive the the place to gain the most from improvements are power suply capasitans. more is better offcource. no less than 20.000uf. (according to me)

-Marius
 
then which amp do u guys think i should build?
i need a powerful yet simple to build amp.

my problem is that the transformers available over here are become really costly once u go above 5amps, so like 10amp trafos are outa of question. so the think is i need an amp which can run on like 3-5amps and can handle +/- 30-50 volts so that the power supply has a greater 'va' rating.

this time i need it for regular purpose that is 20khz to 20hz or something.

that is to power regular speakers.

and could u also send a schematic for opa549? wut do u think of this chip?

along with a schematic of making it a stereo amp.

i hope i am not askin much. i am an amteur so please bear with me
 
hey thanks a lot ,

that AN-1192 file is excellent.

thing is i can directly build the circuits given over there, without adding any thing right? i mean the circuits are correct right?

which one do u think is better ba100 or pa100?

and wut kind of current should i supply through the trafo?

will 5amps give me good enough power (atleast 80watts)?

hey and that guy on that site "shine7.com" he has also built the pa100

with lots of mods and he is using a 500va trafo. but still he says he is just getting 50watts into 8ohms, why is that ?

cuz the amp in the an1192 is rated 100watts?
 
well, given the high impedans nature of the subs in question, i'd go with the bridged amp.

I think sonically, they behave the same, it's still lm3886's either way.
Now, i havn't had a look at that file for a long time, but i think circuts just need a psu and they will do the job.

concider adding a zobel network instead of the output coil. (search: "zobel", "zoble" or "t-network" on the forum)

Why that guy gets just 50w is probably a mix of low suply voltage, and the fact that the paralell amp is meat for low impedance loads, as 4 ohms, not 8 ohm.

ohms law you know. no matter if he had a 50Mw nukelar power plant for power suply, it's the voltage over R-load that matters.
 
hey i have assembled the board,

thing is i am plannin to use +/-30v 5amp trafo.

so do u think it will do it? and i am not using this one to power a sub ok? i just want the amp to play on regular home cinema speakers.

so the thing is i will be building a stereo amp that is total 4 lm3886.

so will 5amp +/-30v be enough? i mean cuz u know the trafos. get real costly once u cross 5amps.

and could u send me a simple regulated power supply schm?

and about the zobel network, i chose the one that carlos has sent.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=39039&highlight=zobel+bridge

so i will need one zobel per chip right so 2 on one bridge ?

i'll send u a pic of wut i mean.

and thats it right no more mods ?
 

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hey i have assembled the board,

thing is i am plannin to use +/-30v 5amp trafo.

so do u think it will do it? and i am not using this one to power a sub ok? i just want the amp to play on regular home cinema speakers.

so the thing is i will be building a stereo amp that is total 4 lm3886.

so will 5amp +/-30v be enough? i mean cuz u know the trafos. get real costly once u cross 5amps.

and could u send me a simple regulated power supply schm?

and about the zobel network, i chose the one that carlos has sent.
http://www.diyaudio.com/forums/show...ht=zobel+bridge

so i will need one zobel per chip right so 2 on one bridge ?

i'll send u a pic of wut i mean.

and thats it right no more mods ?
 

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hey i have assembled the board,

thing is i am plannin to use +/-30v 5amp trafo.

so do u think it will do it? and i am not using this one to power a sub ok? i just want the amp to play on regular home cinema speakers.

so the thing is i will be building a stereo amp that is total 4 lm3886.

so will 5amp +/-30v be enough? i mean cuz u know the trafos. get real costly once u cross 5amps.

and could u send me a simple regulated power supply schm?

and about the zobel network, i chose the one that carlos has sent.
http://www.diyaudio.com/forums/show...ht=zobel+bridge

so i will need one zobel per chip right so 2 on one bridge ?

i'll send u a pic of wut i mean.

and thats it right no more mods ?
 

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sr2002, the 5amp 30V trafo will be fine, though if it's 30VAC, your pushing the limits of chip safe suply voltage. i know first hand they blow if being pushed higher than what's on the datasheet.

now, a 5A trafo is probably too low for a subamp. have you considered using two frafo's in paralell if thats cheaper than a 10amp one?

the amp looks fine, thogh the zoble i see drawn looks like two resistors in series to ground, wich is offcource wrong. i presume you mean the zoble as a R-C link?

Now, as for regulation, for a subamp, this is not only unneeded, but indeed introduces it's own new set of problems. so just trouble and more cast will be the resoult in this case i would say.

a simple regulation design can be found on another of carlosfm's threads.
this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=56106&highlight=

good luck!
Marius
 
hey thanks alot again,

as i told u i am not using this amp to power a sub!!!!!!!!!!!

i am using it to power regular bookshelf speakers.so will i need and noise filters? i was planin to use the filter given in the attached file. what do u think?

i am building a 2-channel amp based on the br100. that is to boards in parallel with the power supply

thats why i asked u whether 5 amp is sufficient? so a total of 4 lm3886 are there in the circuit.

and the power supply that u sent me is looks really complex. do u have anything much simple than that. wut if i use two trafos in series?

and that calosfm has written somethin below "add caps to chips psu pins" what does that mean?
 

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hey ,

wut do u think of this power supply? and i think i'll use 20v trafos to be on the safer side

hey and wut if i connect the 2 trafos. as u said instead of one, and wut if one trafo. is like is 22v and other is 20v or something like.

i mean wut if the 2 trafos are not exactly of the same voltage and amps.

will that blow up the power supply
 
hey, sr2002, I just uppgraded my pc, but my motherboard didn't come with a seriel port, so i cant use my modem no longer.
(abit an8ultra)

so i'm sitting at a friends place right now, but dont have the time to help you right now. I'l try to get on line tomorrow though.

take care
Marius
 

as i told u i am not using this amp to power a sub!!!!!!!!!!!


ok, correction taken.

noise filters?

what do u think?

i dont use any, and if the amp is buildt good enough, then it's not needed i would say. mine makes no noise.

sr2002 said:
wut do u think of this power supply? and i think i'll use 20v trafos to be on the safer side


This is the first of carlo's snubbed psu's, use the one he links to here instead.
http://www.diyaudio.com/forums/showthread.php?postid=534018#post534018

hey and wut if i connect the 2 trafos. as u said instead of one, and wut if one trafo. is like is 22v and other is 20v or something like.

i mean wut if the 2 trafos are not exactly of the same voltage and amps.

will that blow up the power supply

I havn't tried, but i think the resoult would be spectacular.
(so try to use two identical)

hope this helps you out.

-Marius
 
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