Humm from phono but not dc or aux ?

Some cartridges are prone to humming. Grado has a history of this.

@mijostyn To my understanding this has to do with the use of a Grado in a Rega turntable and its caused by the fact that Rega doesn't ground the motor. If you add a wire to ground the motor then the Grado works fine- and its not the only cartridge than can do this in the Rega.

I have an RCM 1 phono stage with external power supply, I just recently just tweaked the dip switched the best I could, not as much hum but at 10 o'clock on volume control more now of white noise and faint RF.

The Cartridge is a Zyx Airy 3 S .24mV

the tone arm cable is Din , Audience Au 24 e

None of this is cheap most likely 5-8000 us dollars.

any other suggestions ?

thx

Eliminating faint levels of noise in a phono stage comes down to methodically checking and testing every single thing involved, trying lots of things to see what works. Faint white noise could be anything from a slightly dirty cartridge pin that looks good, to the way the phono lead is routed, or another wire routed nearby, to even things like lights or appliances. It could even be what you have is pretty normal. Phono almost never is dead silent like digital. But this is why I asked how faint? You still haven’t told us.

@analoghaven, when you say "faint RF", can I assume you mean you are literally picking up a radio station on your turntable input? It happens, so I don’t want to discount that is what you mean as that would be about the only way you now the noise is RF.

If you are picking up a radio station, probably an MM cartridge input? Hopefully you can fix that with a better shielded phono cable than you are currently using, but even that may not work if the cable is not shielded in the turntable, and next question will be is your arm metal or composite. (You can try putting twists in the wires in the turntable / arm if composite).

White noise as @millercarbon stated just comes with the territory of turntables, especially if really faint. If shielding does not fix your picking RF issue, you may need to replace the phono stage. It could be a defect (loading capacitor normally gets rid of RF), or a design flaw.

@atmasphere , Not just Regas. I personally saw (heard) an early Reference do it on a Sota with a grounded motor. When you moved the tonearm closer to the ,motor it got louder.