a few hard for me to find trust able answers

i have a jensen a4000 12vdc input voltage power amplifier power supplyit currently uses 6 2sk1420 mosfets on a pwm ic (SG3525) not sure the frequency it switches at yet but its a self contained power supply within the car amp chassis. the original output section uses the k d718, and k b688 complimetary pair x 4. transformer is center tapped with rail cap values at 35vdc. i am waiting for more 2sk1420 mosfets in the mail still i bought 2 of this diy kit. seller can not give specs. there is a pic of the 2 single channel boards i bought and the power supply. spent a few hours trying to find whats required for power supply voltage and amperage and if its a +/- rail center tapped supply or full wave. also do i need a preamp circuit? ive seen aleph pre stages. i am a novice at this but as these parts are modular in design seem to fit together. i have enough space in the amp for supply / rail capacitance bank and pre amp section if need be as well. my tech terminology is for sure not up to snuff. i just want to run a top shelf custom amp in my car. the soundstream class a's i run are good, i want better.
1678473874135.png
334948107_218272490718184_8209090959705674145_n.jpg
1678473874135.png