Power Supply Regulator for T-Amps

I have several 15V+ switchmode power supplies handy I'd like to try to power up the Sureelectronics T-amp board (max 13.8V). So I'm going to have to cut the voltage down and would like 3A capability. I need something real simple to build, newb here. This seems like it would work:


Is there anything out there that might suit this purpose better? I also saw the LM7812 with similar implementation (low component count), but that only goes up to 1A.