I would use an extension, like a power strip from the conditioner, for the wall warts. (and I DO!) I use an old Adcom conditioner just for the WiFi and a powerstrip for my phone charger, the Laptop charger, a nearby lamp. I used to also have the wall wart for my Rega P5 turntable in it too. but recently moved that wart to a Furutech GTX duplex. Make an extension.. get a dual duplex box at Menards etc, stick in two duplex, wire it up. Plug it into the conditioner.
When I had more room, I used a Furman with separate filter sections. That kept any wall wart noise 2 filters away from audio devices, while everything was protected.
I don’t have that kind of room, so I use a smaller Furman and a separate conditioner or a linear supply.
I use a Raspberry Pi as my digital music streamer, and a separate linear supply for my DAC.
I rely on the DAC having galvanic isolation (ground loop) and noise and jitter rejection built into the USB receiver. Those have gotten much better lately, probably thanks to cheaper chips which do all of this for you.
I have any some success reducing noise when plugging a switching power supply into a power conditioner. Audible results most often with turntables. Power conditioners can also ensure the power going into the switching power supply remains clean and stable.
Chuck, you can use a linear power supply (LPS) and get rid of the wall-wart. A LPS uses a toroidal or R-Core transformer instead of the switched mode PS found in the cheap and noisy W-W. The result will be a significant improvement in sonics; better dynamics and detail, larger soundstage, lower noise floor.
You just need to know the voltage and amperes needed to run your TT.
What twoleftears says. Certain power conditioners have isolated banks: e.g. Isotek. Otherwise I agree with others that doing a separate power strip with all wall warts / smps in it - and have that into a different outlet - is best. This helps - but doesn't solve the problem. A bad / fault PS can still bleed the noise back to the main panel, then eventually to your gear.
SMPS warts on a conditioned power supply sounds kinda silly to me unless every outlet on the thing is independently conditioned and isolated. They don't just make noisy DC power, but they put noise on the supply line. What's more, if the SMPS is half-wave rectified, it'll put a DC bias on the supply line.
@chuckjonez another thing to consider is that the power cable itself, running from the power adapter to the turntable, can pick up noise. Even with a linear power supply. You'll want to make sure to keep the power cable away from other cables, particularly if run parallel to other cables, if that is something you experience.
Based on input here, I bought a Signature Edition Swagman LPS for my Project Tube Box DS phono preamp to replace the stock SPS. I agree with lowrider, the Swagman is excellent.
I had tried another Chinese built LPS with the Project that I borrowed, and found that sounded bass heavy and dull, so went back to the stock power supply which was tipped up a bit from neutral, but it has good drive. The Swagman takes the Project and my enjoyment to and entirely different place, everything is better. Ridiculously better. A Very good deal in terms of the build quality and performance. Can’t speak to the stock model, but the Signature Edition is great.
I previously replaced the SPS on my Arcam irDAC with an MCRUS LPS with great success. I looked at the MCRUS supply for the Project preamp but souped up versions of that are twice as expensive as the upgraded Swagman, so thought I would try it. Not disappointed.
Perhaps not surprisingly, getting the Project SPS out of my power strip makes the MCRUS/Arcam DAC sound better too. I am using a Shunyata Venom PS8 power strip, Venom HC supply cable and Venom Defender power conditioner, and while this is extremely clean sounding, I am certain the isolation is not as significant as more sustainable conditioners. I have all sources plugged into the Venom, amp and sub are plugged directly to wall.
Anyway, plus two for replacing stock SPS with aftermarket LPS.