Two people tested those BECs, and got the following results:
5.5V at 0.5A
5.45V at 1A
5.35V at 2A
5.15V at 4A
5.02V at 5A
Amp Volt
0 5.5
1 5.4
2 5.28
3 5.17
4 5.08
5 4.96
6 4.79
7 4.6
Is that normal for a buck regulator? I'm not sure if my circuit can take 5.4V, but I don't want to have to use one of these set to 6V and feed that into a linear regulator. Then I'd be limited to 2A.
I know the atmega has a max rating of 6V. I guess I'll have to check the dac and amp. A 5.5V supply would probably cause some clipping in my amp though since it expects 5V. Then again maybe because Vin on the amp would be higher as well it would just result in a higher output voltage to the speaker. My SD card should be fine since I have a 3V regulator for that...