DDL driver power

I am planning to use 4-AA's but I hear it can sag and cause a spike that will kill the LD.
Is that true?
And how do you change the current/voltage?

Well, I have heard that too. I ended up using 6 NiMH AAs at 1.2V.
That gives me about 7.2V of input which is what you want for a red
using the DDL driver. Your output with a load attached should be somewhere
around 2.5 to 3 volts. I also read on here somewhere to never use alkaline barreries.
Use rechargable NiMH.

As far as adjusting the current you would just turn the adjustment screw on
your pot or hard set it with resistors. If you haven't built the test load for the
DDL driver you will want to do that. You do not want to try setting the current
with your LD connected. Use the test load circuit to measure your voltage and
set your current.