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OPA3690 in a CMoy? How to do that?

post #1 of 13
5/7/11 at 11:01pm
Thread Starter 
Hey Guys,
i am trying to build myself a CMoy for iems.the OPamps that were decided were the OPA690 and, the OPA3690 (3xOPA690s in the same package) because of low voltage requirement and unity gain stability. Now i know how to work 2xOPA690s into the CMoy, but how do it do it with the OPA3690?how do i use it in the CMoy.i think it would be a buffered cmoy,but i don't have a schematic to such a CMoy.
Thanks.
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post #2 of 13
5/8/11 at 5:26am

I think the first thing you are going to need is an etched board.

Whether you etch it or get it done at a board house is up to you

and your skill. OPA690 (OPA3690) it too much for a bread board

project. The schematic is pretty easy, it's the execution that

is the hard part...

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post #3 of 13
5/8/11 at 10:49am
Thread Starter 

Cant i just have some instructions?

how would i use an OPA3690 in a CMOY?

not just use, what schematic should i be looking at?

an OPA3690 would mean 3 OPamps. u said i can put three in a CMOY, that means it would be Ground Buffered as the Mini^3 is, right?

i need directions, please....

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post #4 of 13
5/8/11 at 12:05pm

I'm getting the feeling that maybe you should start out with a less ambitious project

to get the hang of building your own amp. Tangents tutorials are a great place to

start and he has an excellent CMoy build article. The OPA690 takes a fair bit

of skill and understanding to get working properly and I don't think you are there

quite yet.

AMB's Mini^3 is a great amp and if you build that then you will have an amp

more satisfying than a simple CMoy. Again, though, it might not be a good

project if you have not built anything before.

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post #5 of 13
5/8/11 at 1:00pm
Thread Starter 
Hey Avro_arrow,
i've been there before. I've built 2 Headbangers (based on LM386, man these things are devils), and the CMoy too. A Mini^3 is on its way to be built. And, i've been diying since i was a kid, i just can't figure out what i have to do here.
Maybe its ambitious, but hey, isnt that the thing about DIY?
I guess i'd be landing with an OPA690, but i have been confused from the moment u mentioned the OPA3690 in the CMoy.the simple CMoy uses a dual opamp, the CMoy2 is buffered as in the Mini^3. But how do i use a triple opamp in a cmoy?and what use would the third be?
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post #6 of 13
5/8/11 at 2:06pm

Left channel, Right channel and Ground buffer.

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post #7 of 13
5/8/11 at 8:26pm
Thread Starter 
And i should go according to the Mini^3 schematic or what?also, how much voltage would it need now?
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post #8 of 13
5/9/11 at 12:18am

 

has anyone made one of these guys? i snagged this kit from ebay thinking it would come with step by step directions. has anyone bought one of these ebay kits from china? 

 

i'm a straight up noob, but i thought this would be a decent project for my first diy amp. 

 

any thoughts and suggestions would be greatly appreciated.

 

Photo on 2011-05-08 at 18.jpgPhoto on 2011-05-08 at 18.jpg

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post #9 of 13
5/9/11 at 1:48am
Thread Starter 
Do u know how to read a schematic?
I have seen the very same documentation, rather more detailed on the internet. Search for Simple Cmoy or simplest cmoy, using google images.when u find anything/image like the lower half of the first image u uploaded, open it and read the instructions.otherwise,learn how to read schematics, what is what,and assemble the amp.
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post #10 of 13
5/9/11 at 2:09am
can you post link of where you got it? The ebay product. Thanks
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post #11 of 13
5/9/11 at 2:33pm
Quote:
Originally Posted by psgarcha92 View Post

Do u know how to read a schematic?
I have seen the very same documentation, rather more detailed on the internet. Search for Simple Cmoy or simplest cmoy, using google images.when u find anything/image like the lower half of the first image u uploaded, open it and read the instructions.otherwise,learn how to read schematics, what is what,and assemble the amp.


i can't read schematics, but i'd like to learn. 

thanks for the tip. i'll do that exactly. 

 

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post #12 of 13
5/9/11 at 2:34pm
Quote:
Originally Posted by randomkid View Post

can you post link of where you got it? The ebay product. Thanks


i can't sorry. i bought this several years ago and i don't remember the seller. 

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post #13 of 13
5/9/11 at 3:03pm

Go to ebay

 

search Cmoy

 

bingo

 

cheers

FRED

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