[time-nuts] potential low-RFI power supply

[jimlux]

On 5/17/20 11:53 AM, Eric Scace wrote:
> Pro Audio Engineering announced a sale (through Friday) on its nominal 14 Vdc 4A switching supply <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/>. The test results <https://proaudioeng.com/products/pae-kx33-low-rfi-ac-power-supply/> webpage compares noise on the DC output and noise frequency spectrum under a variety of conditions with a lead-acid battery, an Astron linear supply, and a variety of switching supplies from other manufacturers.
> 
> I have not used this and can’t vouch for its performance. Given recent discussions here on supplies, the analysis might be interesting. At least the supplier has attempted to quantify the performance of its power supply and make that information available to the prospective purchaser.
> 
> It would be interesting to see comparable (or more suitable) measurements made by others posted here.
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Interesting.. It would have been nice to see spectrum analyzer plots 
from, say, 0 to 1 MHz with a much narrower resolution BW.   1 MHz/div 
with 300 kHz RBW isn't going to show the "row of discrete spurs" that 
the switchers put out.

4mV ripple isn't bad, or at least, it's better than most of the other 
switchers.  The Astron linear is given as 5mV, but the scope photo 
doesn't seem to show anything. At 5ms for the whole screen, you should 
see some variation for over the 8.33 ms ripple period.


I get that they're demonstrating the performance with a specific 
transceiver load - but I'd be interested in seeing measurements at zero, 
50%, and 100% load on a switcher.