For those who haven't seen it yet, the op amp measurements article has been published. You can see for yourself, but at 2.5X and 3X gain the NJM2068 matches the distortion, and beats or matches the noise performance, of everything else. At 7X gain it has a max of 0.0018% THD+N at 2 volts around 7 Khz which is still really trivial and well below the goal. While the NE5532 does better at 7X gain in terms of distortion, it has 3 dB more noise and requires about 1/3 more current which will slightly degrade battery life.
Those running high gains are probably not going to be using ultra sensitive IEMs where noise can be an issue. So, generally, I doubt the 3 dB extra noise with the NE5532 will be an issue for most users. But I'm equally confident neither will the trivial HF distortion of the NJM2068.
So take your pick when you order parts. Or for an extra $0.65, you can just get both.
Those running high gains are probably not going to be using ultra sensitive IEMs where noise can be an issue. So, generally, I doubt the 3 dB extra noise with the NE5532 will be an issue for most users. But I'm equally confident neither will the trivial HF distortion of the NJM2068.
So take your pick when you order parts. Or for an extra $0.65, you can just get both.
HEADS UP! I was hoping I was just being paranoid, but my caution not to buy parts yet has already proven to be good advice. There's a BOM change and the details are in the other thread here:
BOM CHANGE
I'll have the new docs up shortly. Sorry about this. There's a workaround if you've already ordered your parts.
BOM CHANGE
I'll have the new docs up shortly. Sorry about this. There's a workaround if you've already ordered your parts.
You won't see me make any claims for experience, but I'm having a look using gerber-viewer.com. I see something odd to me with the C17 connection to ground. Also the trace next to it at the ground end, beside C13. Doesn't look like a jumper... what is it?
ps maybe I should point out it is in the "nwavguy o2 v11 top layer.GTL" file
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I'm afraid not. Getting the parts for us Brits is very easy though - bulk of them from Mouser and then the rest from Rapid Online.
Do you want just a PCB?
Also, please put technical queries in the O2 Discussion thread:
http://www.diyaudio.com/forums/head...headphone-amp-diy-project-15.html#post2677755
It is better to run this thread with just the board orders and the big news updates if there are indeed any changes.
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