If need is lower 7-9 V from 12V output, can we just lower the R parallel to the last C

[abdulbadii]

There're 12 Volt 5-6.5 A SMPSes availabe in market but the need is the lower 6-9V on such rate, so can we just lower the R parallel to the last C on output or it's too risky to safety?

 

[crutschow]

can we just lower the R parallel to the last C on output or not

No.
All that would do is increase the current from the supply.
The voltage won't drop until the supply reaches it's current limit.

What voltage and how much load current do you need?

 

[rjenkinsgb]

No.
You would need to change the resistors in the feedback circuit, so it regulates to a lower voltage. How you do that depends on the design of the specific PSU.