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Low cost high quality excellent performing LPSU for audio.


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49 minutes ago, plissken said:

The problem is this is 100% bullshit. There are crap SMPS just as there are crap LPS's.


Ah, the ever profane and incorrect Mark Brown. x-D

Yes there are a lot of LPS’s whose performance is poor for various reasons—typically high output impedance.

But @airguitaris correct to state that SMPS typically have much higher output noise than a decent LPS.

 

Proof? Let’s take this to the extreme with the example of the absolute lowest output noise SMPS available as far as I know: The Daitron RFS50A: https://www.daitron.com/documents/RFS50A_Catalog_En.pdf

Most modest-current SMPS units will specify about 80mV (80,000 microVolts) of noise. The wonderful Daitron offers 1mV (1,000uV) output noise. That is indeed outstanding for an SMPS, but in 250 unit OEM purchase quantity the thing is still, last I checked, $302.

Building an LPS down into the single-digit milliVolt range is trivial (though as discussed, DC output noise is not the most important criteria for an “audiophile” LPS—or at least not the only one.

However, advanced LDO regs such as the LT3045 make producing supplies with output noise in the single or teens digit microVolt range pretty straightforward.  Of course there are numerous other PS design considerations—and the LT3045 maxes out at 0.7A (most designers pile a bunch in parallel for more current; or choose from the wide world of higher current LDOs still in the microVolt noise range).

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2 hours ago, Miska said:

Well, it doesn't have ground leakage because it doesn't have ground!

 

We never said ground leakage. Leakage is common-mode!

 

I have a whole series of leakage measurement graphs taken from a Mean Well GSM40B "medical" SMPS and for the form of high-source-impedance leakage John has been explaining, they are no better than any of Mean Well's non-medical models.

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