iFi audio iPower X - The Official Thread

Does this new iPower X have a UK three pin plug? If not how do you pluck it in?

 

I guess if you buy it in UK It will have UK pin. It depends on the market you buy it from.

 

That's correct!

 

I run an iFi iPower DC-9V.



After reading the iFi claims that it is much less noisy than a typical Linear Power Supply, I decided to measure the noise with my Fluke multi-meter.

I measured a solid 1.4mV of noise - which I think is pretty typical for any decent SMPS.

Not sure how the iFi ~1uV noise specification is justified.

What am I missing here? Happy to be corrected.

 

You are missing both an earth ground and proper shielding to make a correct measurement.

Your Fluke meter is battery operated and floating with respect to the EMI / RFI environment. Stray fields will swamp the power supply measurement. Measuring an iFi power supply with a Fluke 189 and no shield or ground reference I observe 0.282 mV in my EMI / RFI controlled environment. When a ground reference is added the Fluke 189 measures iFi PS with a residual noise of 0.034 mV. However, the same measurement with a ground referenced Keysight 34461A , less than 1uV of residual noise is observed.

Typical for SMPS varies considerably depending on design goals across the various SMPS. Some can be very quiet. Most are much noisier than your claim. See this thread for further consideration:
https://www.superbestaudiofriends.o...ise-nuke-for-hp-amps-with-external-smps.5142/

 

Could someone explain this to me, wouldn't the active noise canceling of these ifi ipower actually increase noise in the signal chain? If the circuit is injecting a sound into your chain, even it it is an identical wave of what it hears, it's still extra noise in the chain. Maybe I'm over thinking this all though.

"iPower X uses our latest Active Noise Cancellation 2 (ANC2) technology to cancel all incoming EMI/RFI noise. This technology is, in principle, similar to how active noise-cancelling headphones work. The intelligent circuit inside of the iPower X measures the signal coming from the mains and injects an identical wave of the opposite-phase. The result - the initial wave and its mirror reflection interfere destructively cancelling out all noise pollution."

 

Unless I'm mistaken, they're using phase cancellation to nullify the incoming noise from your AC mains. So the signal the device is adding to the power line is the inverse of the incoming RFI/EMI noise, added together they cancel each other out. If you have software capable of generating audio signals you can try playing 2 separate 1khz sine waves, with one 180 degrees out of phase from the other, if everything is working properly you won't hear any sound, then remove or invert one of the sine waves and you will hear a 1khz tone.