The Samsung Galaxy Tab P1000 charging unit, that you refer as a brick, has the following specifications:
INPUT : 100.240 Volts AC, 0.35A 50/60 Hz
OUTPUT: 5VDC, 2A
So, if you do not have that charging brick, getting an USB power source with those specs: max: 5V DC and a current of 2A should be able to charge the tablet, using the same original cable: USB on one side and the Samsung proprietary connector on the other.
The Tablet itself (at least the one I got Samsung Galaxy Tab 10.1 original model and model number P7510) states on the back that it requires an electrical feed of 5V 2A
USB 2.0 and USB 3.0 specificacions say that the maximum allowed current drain is 1.5A , if the Tablet demands 2A and because of this, then a USB port on a modern personal computer will NOT be able to charge it.