\rHi Pedro:
The AMP-300 will do a great job. You would connect speaker A of the AMP-300 directly to the first OM-SUB200 four conductor inputs (R&L, +/-) then connect a pair of the AP-525 to the four conductor output (R&L, +/-) of the OM-SUB200. Then repeat the setup with the second OM-SUB200 and AP-525 to Speaker B of the AMP300. You will be able to play Speaker A or Speaker B or both Speaker A and B at the same time. It also makes it easier to run a four conductor cable like our CL3/FT4 14/4 (direct burial) from the Amplifier to the OM-SUB200. Then run 2 conductor 14/2 to each AP-525. Also check out our Aqua Blue Waterproof wire nut connectors for terminating the Speaker Wire to and from the OM-SUB-200. This amplifier is also multi Voltage where it can be plugged into either 115V or 230V. The AMP200 would also work for your application. It features the same design but a little less power.
Good choices...
TL/3809\r