PSU noise pollution: iFi, Meanwell, Teddy Pardo, UpTone JS-2 and others

[Jud]

3 hours ago, Elberoth said:

Alex,

 

I value your feedback very much and highly encoureage everyone to join the discussion.

 

I know that a single digit meter is not a perfect solution. However, with all its limitations you can see a certain patterns here - namely, cheap SMPS in general generate much more noise than more expensive ones, designed with EMI radiation in mind (iFi iPower for example or genuine Apple iPhone charger vs chineese knock off). 

 

BTW - Cealin Gabriel (the CEO of Shunyata) have posted this info on another forum:

 

I have several of the Alpha and the Stetzerizer units. Personally, I prefer the old Entech unit. Entech was actually a very technically advanced group of engineers. Both the Alpha and Stetzerizer are similar in that they have a bandwidth that extends quite low for measuring RFI/EMI. They drop down to 15-30 kHz in there measurements. While this may seem to be an advantage it actually has a fatal flaw. Both aggregate noise from about 15 kHz to around 10 MHz and lump them all together in a single reading. Some frequency bands are more important to the performance of audio equipment specifically our research indicates the the most harmful frequencies are in the 100 kHz to around 1 MHz bands and then secondarily from 1 MHz to 10 MHz. Interestingly, I believe that the Entech engineers knew this and designed their device to be sensitive in the frequencies from 300 kHz to 700 kHz range. This makes the Entech particularly useful for finding noise sources in the specific ranges that are most noticeable in the context of music systems. 

I have done direct side-by-side comparisons using all of the units listed. I would then plug a device into the power line that we 'know' produces particularly harmful noise effects as measured by our power and spectrum analyzers. In many cases, the Alpha and Stetzerizer would barely change their relative readings while the Entech would go off the charts. This is because the Entech is more narrowly focused and the other two are less so.

And then conversely I would connect filters that reduce power line noise in a known manner as verified by the power and spectrum analyzers and in many of these cases the Alpha and Stetzerizer would show only as small or marginal difference while the Entech would show a much larger and significant difference. 

Look these are all very inexpensive devices and all of them can be useful. But they have severe limitations from a technical point of view. I found the most useful for the hobbyist to be the Entech. As I said earlier, we are developing a device that will be much more useful and will show noise in specific bands much like the old audio spectrum displays. This is being developed for our medical division where this device will be quite useful in identifying specific types of noise pollution in hospitals. I hope this is helpful.

 

You may have noticed that he places much greater importance on the freq in the 100+kHz bands as more important to the performance of audio equipment. In other words - he doesn't seem to think 10kHz meter limitation is a problem.

 

 

 

 

 

 

 

Hi Adam.  I would be very interested to know if any reason is given as to why these MHz frequencies should be important.  A link is fine because I don't want to get off topic.

[Jud]

47 minutes ago, Elberoth said:

 

The original thread:

 

http://www.audioshark.org/power-conditioners-regulators-24/measuring-ac-power-line-noise-11713.html

 

Thanks, very much appreciated.