Ok, I've narrowed down my three choices in buying a new amp to push my JBL W12GTI MKII sub. I've only got one sub and I'm gonna take the advice I got and run it in parallel to get to a 3 ohm load. The 3 amps I'm looking at are 1)Alphasonik PMA1000DE (1150-1300 watts) 2)Alpine PDX-M12 (1200 watts) 3)Soundstream RUB1.2500D (1200-1300 watts). I'm being told that this 1 sub can handle 900-1000 watts all day long. I'm not sure if that is 100% accurrate or not. My budget is $400-$650 to spend on an amp (online ebay, amazon prices). What amp would be the best one to get? If you have another amp that you think would be better, please let me know.. Thanks
From those you mention I would pick the SS RUB1.2500D its fairly priced ($329) unlike the Alpine an I really prefer it to the Alphasonik.
Only seems too much power for that sub.
Other things to consider is that a sub's ability to take power resides in a properly custom designed enclosure, and use of subsonic filtering also help.
The JBL W12GTi MkII like you mentioned above, is able to handle more than it's rated 700 Watts RMS. I notice it is more common to run this subwoofer anywhere from 900-1200 Watts RMS and the results look pretty promising, as long as the enclosure it's put in is built to spec.
As far as the Amplifiers that you mentioned above, they will all be able to get the job done, but personally I would choose the Alpine PDX-M12. Not only is it a higher quality product, but it is rated to produce 1200 Watts RMS across the board from 4 Ohms to 2 Ohms, which is will provide you with a wider variety of system configurations that you can do.
Newer Alphasonic products these days are overrated. Soundstream was a great brand back in the day, but it seems that the quality of their Amplifiers have decresed over the past few years IMO.
Overall, if I had to pick my own Amplifier for your Subwoofer, I would personally look into a Kicker ZX1500.1, Rockford Fosgate T1500-1bdCP, JL Audio Slash v2 1000/1v2, RE Audio XTX-3000.1 or XTX-5000.1 (for more RMS).
Of course, there are plenty of Amplifiers out there for you to pick from. Just make sure you do your research before buying any Amplifier to make sure there isn't a poor quality product or common issues.