Need help with Sound Card headphone amp

So I've been looking everywhere and I can't seem to find any technical documents for my sound card that lists the information I'm looking for. Basically I'm trying to figure out how many mW the headphone out amp can power. I just got the JVC HA SZ1000. It's only 16ohms but it needs a shit ton of power. It says it can handle 1500mW :pt1cable:. When I'm using my sound card the bass is just not really there, but you can feel their's a beast begging to come out. So I found a few documents but they weren't giving me the exact answer. I'm using a Asus Strix Soar sound card,from the Asus website they say they are using a SABRE9006A DAC within the sound card. I'm assuming this is also being used to amp the headphone output. So my question is, does anyone have any idea of how many mW this sound card can output at the headphone out?

Headphones
https://www.amazon.com/JVC-Kenwood-HA-SZ1000-Victer-Headphones/dp/B00CIQ88UI

Sound Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16829132100&cm_re=asus_strix_soar-_-29-132-100-_-Product

Sound Card Manual
http://dlcdnet.asus.com/pub/ASUS/Audio_Card/Strix_Raid_DLX/E11113_Strix_sound_card_series_Manual_web_only.pdf?_ga=1.81733719.1564773567.1475450733

SABRE9006A
Premier 8-Channel Audio DAC (listed in the sound card manual for what power the headphone output)
http://www.esstech.com/files/4014/4095/2155/SABRE9006A_PB_v0.4_140916.pdf

Thanks in advance for any help with this.