Twist B+ and B- wires ?

[RhythMick]

Hi. Building balanced phono stage with B+ and B- (later doing similar for line stage).

Point to point wiring, separate boards for mounting components on each channel.

So each board will have B+ (250VDC) & B- (-250VDC). The B- drives the shared cathodes in differential amplifier valves, with obviously separate loads to the B+. Ground bus in the middle of the board.

Should the B+ and B- wires be twisted to help with PSRR ?

 

[rayma]

Should the B+ and B- wires be twisted to help with PSRR ?

This is most important in class AB power amps, and sometimes for op amps. There, twisting the positive,
negative, and ground leads all together can make measurable improvements and reduce noise,
because each supply line does not carry the complete signal current (at higher levels).
In class A circuits, twist each single supply lead and ground together to minimize the loop area.
Consider how the signal current flows. A local decoupling capacitor close to the circuit is still needed.

 

[RhythMick]

Balanced power supply, so there is only one ground (B+, B- and Ground). Minimising the loop area - right. I'll twist all 3 along the board, to 2 "stations" where each can be connected to. Instead of a ground bus I'll star ground.

Thanks