[bavman]

Hi guys,
 
I was looking to make my own O2 amp since its a lot cheaper than buying premade. Looking at the BOM here:
https://docs.google.com/file/d/0B52Awjeyc5zKYWViZjlhNzItZDBmYi00YjA4LTk1NzgtZTMwNTAzMWQ3Y2Iy/edit?hl=en_US
 
It seems that the first section includes all the parts needed and comes to ~$27 on mouser, and the PCB is $6 on JDSlabs. Those parts + a power adapter (or batteries) is the only thing I need to getting it up and running correct?
 
The only thing that's confusing is the section called "gain resistors". Do I need any of those to make the amp? I don't think they show up in the documentation on building it.

 

[Crispy808]

The gain resistors offer builders the option of adjusting the gain.  By default, the gains are 2.5X and 6.5X if you use R17/R21, R19/R23.  If you're viewing the BOM as an XLS file, these resistors are contained in lines 31 and 32 of the spreadsheet.  So no, you don't need the section called "gain resistors" if you're content with the default gains.
 

 

[bavman]

Thanks! sounds good.
 
Only problem now is that this op amp (513-NJM4556AD) is OOS until the end of January:
 
http://www.mouser.com/ProductDetail/NJR/NJM4556AD/?qs=sGAEpiMZZMtCHixnSjNA6NG6IBDWSupwCYRdp%2fZHdxY%3d
 
 
But there is a very similar one (513-NJM4556ADD) that is in stock. I'm not what the extra 'D' at the end of the part number is. The documentation for each model lead to the same PDF describing the same product so is it safe to assume I can substitute the in stock one
 
http://www.mouser.com/ProductDetail/NJR/NJM4556ADD/?qs=sGAEpiMZZMtCHixnSjNA6NG6IBDWSupwY9fq5mj%2fn2A%3d

 

[Crispy808]

I didn't want to wait for the OOS item so I went with the ADD.  Perfectly fine.
 

 

[bavman]

Greatly appreciated. Thanks again

 

[Crispy808]

No problem.  Hope the build goes well.  It's pretty addicting making this stuff.  Even though the O2 is plenty, I'm looking for my next build.
 

 

[bavman]

Yeah me too haha. I wish the ODAC had a DIY option