Hey, I have 2x meanwell rt 65 b P/S. (9u case NANO BUS BORDS)
I have really bad noise problems. I puted 2 ferrites on wires before they go in bus board but it didint help.
Am looking on NKP (noise killer plugs), but not shure will it help.
I have noise only on filter modules. I user erica synth vcf1 and wasp filter.
If I put lfo in filter cv input then filter out to mixer (no audio input in filter)
I can hear lfo sweeping noise when audio is at 30%+ I need put my Volume at 20-29% so there is no noise.
If Only Filter module in case noise is there to.


In my experience, that's how Meanwell power supplies are. Supposedly the noise goes away if you put a dummy load on the 5V line, but you'll never get a straight answer from anyone online as to how to go about that (don't ask me, nobody would tell me, either) because everyone assumes you'll kill yourself. These power supplies are not designed for powering modular synthesizers and can't really be relied on to be stable voltage sources. They're primarily intended to be used as 5V power supplies. You're paying for what you get. I used to have one in a small case and you could hear the pitch drift in the oscillators, they were never totally stable. I switched to an Endorphin.es 2hp power supply for that case and it cleared everything up.


Supposedly the noise goes away if you put a dummy load on the 5V line, but you'll never get a straight answer from anyone online as to how to go about that (don't ask me, nobody would tell me, either) because everyone assumes you'll kill yourself.
-- milkmilklemonade

I don't have one of these supplies so I can't speak to specifics of the noise problem, but a dummy load is just a big resistor from power to ground to ensure there's a minimum load on that rail by wasting a little energy as heat. As a wild ass guess based on that supply's specs (https://www.meanwell.com/productPdf.aspx?i=484 - 5V rail 5A, and they want 20%->1A minimum load) I'd probably start with a 10 ohm 50 watt (like https://www.amazon.com/LM-YN-Wirewound-Electronic-Industrial/dp/B071Z8B9FN) which will be a 0.5A load, and experiment from there with a second/third in parallel. The actual amount "required" will depend on the other 5V load in the system, and if it does help you'll want the smallest load that solves the problem, to minimize the wasted power/generated heat.