I have a power supply board. Its used with a mosfet amplifier, its tone control board, a usb module and a computer fan. Output is 34v dual, 15v dual 12v and 5v. The transformer I'm using has three voltage outputs. 27v dual,18v dual, and 12v dual. The power supply is a nice one. All the ground from the output of PSU and grounds in the inputs are well connected on the PSU board. My doubt is , is it ok to connect all centertaps on the transformer together and then connect that wire to the ground of 34v dual input or is it necessary to connect all centertaps with the their individual inputs on PSU. Im in a situation to place transformer ceperately due to lackof space. I assembled that PSU. The brought that board and assembled all the parts. There's a place for 10nf caps across all the diodes in PSU.I think its used to reduce noise. Is it ok to use a disk type cap or does it need a polypropylene or something?
If you tie the center taps together, you remove the isolation each winding provides. This may or may not be an issue depending on the design of the circuit. Without knowing the circuit, it's hard to say.
Circuit is bridge using four diodes and two big caps.and they provide dual 34v supply. Same for 15v dual. Only the 12v uses full bridge for single supply. It is it's further regulated using 7805 for usb module. Neutral of all are connected at the output and they goes seperately to the input. ( no interconnection at the input.
You talk of grounds and neutrals. Are you referring to mains wiring neutrals? When you say 'grounds' do you mean the 0V wires? If so, you are using a bridge rectifier so you cannot connect the transformer centre taps to the ground of the 34V.
Draw a circuit. One picture is worth a thousand words!