hi i was looking at buying me a single 10 inch sundown audio sa sub and was wondering would the jl audio 300/2 amp be enough to power the sub without under powering it ?

There is no such thing as underpowering.

Build it a bigger box. 

Don't try and compensate by turning the gain up & bass boost. That could kill the sub.

Since there no such thing as under powering a sub does anyone know if the amp will be enough power to push it.

it will be fine,.

You already have the amp, correct? Then buy the sub and try it out.

50 watts is enough to get that sub loud in the right box.

BTW, no matter what you do, it will be impossible to thermally blow (with your amp) that SA 10 unless the RMS rating is inflated.  So don't worry about that part...

 

You almost get a green light to do whatever you want with bass boost, eq, volume, etc with this combo, above enclosure resonance.  It usually isn't like this, lol...

like already been said, the gain on the amp is NOT a volume control and also if you build a larger enclosure it will help compensate for the lower power levels.

Build the enclosure for desired response, not system power