Designing to minimize power supply noise

[mag_therm]

I would suggest to connect P close to the incoming power supply and the other two Q & R, initially connect them together to a ground bolt near your output bnc's.
Are you using the twinaxial BNC connectors as shown marked "out" on you diagram?


I recently finished a pwm dc-dc converter project were noise mitigation was a priority.

The dc-dc converter acts as a boost regulator, sitting on the unregulated 5Y3 + 125V anode voltage rectifier of a Lafayette HE30 HF receiver.
The +V supply runs all over the receiver wiring including to the plate and screen of the first RF stage.

I have no way here to measure the noise on output of the dc converter except it has on/off switch which shows no change in the reception noise.
The dc-dc converter is mounted in a separate steel chassis with plated steel floor, allowing short bolted grounds to the circuit.

The only problem I have yet to fix is that when a strong signal or RF gain control sends the tubes far into cut-off,
the inverter phases right back to the bottom of the sawtooth and bounces there causing loss of regulation and  AF noise.