Has anyone tried using a double UPS for clean power?

@mulveling  I haven’t had coffee yet but isn’t that how all regeneration works. AC > DC > AC? So what's a "double UPS" the OP mentioned?

It’s a single UPS unit designed to internally convert the wall AC to DC, and then from DC back to AC (hence the "double conversion"),

GOLDENMATE 2000VA/1600W Lithium UPS Battery Backup and Surge Protector, Backup Battery Power Supply with LiFePO4 Batteries, AVR, Online Double Conversion Uninterruptible Power Supply, Pure Sine Wave https://a.co/d/iWWUKe6
 

 https://a.co/d/9ZoPTJ8

Don’t know why the hyperlink didn’t come through on my previous post, but this is one of several examples being sold on Amazon. APC sells them as well.

This is part of the description of this unit.

• [Professional Online Double Conversion UPS]: The 2000VA/1600W Pure Sine Wave Online UPS ensures uninterrupted operation with zero transfer time (0ms) power switching, safeguarding mission-critical systems from outages and voltage drops. Its dual-conversion design delivers clean, stable power, fully isolating connected equipment from utility disturbances. Featuring Automatic Voltage Regulation (AVR) and intelligent battery monitoring, it optimizes performance and extends system reliability. Ideal for offices, healthcare, retail, industrial, and government applications, this UPS provides seamless, dependable backup power to keep your essential operations running without interruption.

I have not attempted this, but my thoughts are this is a lot of effort for mixed results. 

Whether it’s jitter or power, the order of power supply/de-jitter devices really matters.  At the end it’s often hard to tell you’ve made any improvement, and often you’ve swapped one kind of noise for another. 

For instance, with anti-jitter devices, the device itself may have more jitter than your original device had natively.  With a UPS, sine wave generation (i.e. the inverter) may leave high frequency or EMI/RFI noise on the line.  

The ideal situation IMHO is when a power supply does additional buffering inside itself.  For instance, the Krell fully balanced amplifiers or the Sander’s Magtech.  That way the engineer knows that the direction of noise reduction and current availability is constantly going in the right direction.  

Personally I go for Furman with voltage regulation (AR) and series mode protection for this reason exactly.  It goes from unregulated AC from 110 to 140 V (or something like that) and delivers a stable 120V +- 3VAC, which then feeds the noise and surge filtering.  No additional EMI/RFI introduced, and my downstream power suplies get pampered with a reliable AC source. 

My advice is to minimize the layers of power conditioning and make sure you keep particularly noisy sources OUT of the cleaned power.  For instance, if you have a very expensive power conditioner, don't put your PC's power supply on it.  Keep it separate, maybe on it's own UPS or surge strip.  If you put it on the post-conditioned side you run the risk of injecting noise to an AC source that's already been cleaned.