power supply crossover diy

excuse my English
My amp is for lm1875 tweeter and woofer for lm3886.
The system is 7.1.
Bi amplified.
My crossover has 28 Ampop (NE5532). Linkwitz-Riley Electronic Crossover
I do not know which the power transformer, for the power suplly crossover.

So, you are building a power supply for an electronic crossover? 20VA may well be enough in that case. The NE5532s can draw as much as 16mA per chip, so 28 will require 448mA maximum. As long as your power supply can handle that, you should be fine.