Responses from carlsbad

Making DC power cable with 3 wires
size of wire and current?  
Let's see your office systems
https://photos.app.goo.gl/dSi8o7fRUM8GA1Yw5 Normally just the Kinki amp.  This day I was trying the Decware to see how it drove the very difficult load ML CLS. Jerry  
In a speaker crossover, are film inductors directional or have polarity?
I think you mean film capacitors.  While they usually aren't directional, often it is seen as better to hook one end to positive.  they are usually marked by a long lead or a mark established by the OEM.  Jerry  
would innuos mk3 streamer benefit from network filter
I'd look at the DAC.  DACs can be harsh. All a digital streamer can do is send more bits to the DAC.  I also don't think wires are generally harsh.  If I wire sounds harsh, it is carrying the harshness from a component. Jerry  
Should I
If this is your main system amp, then yes, I would recap for reliability and hopefully better sound. Jerry  
Mastersound evolution 845 vs. Jadis da88s vs auris forte 150
Haven't heard these but Decware amps handle low resistance loads well.  Jerry  
Fiber to my Etherregen… Sonore OM or generic?
Conversion is an error likely, potentially noisy process.  If your internet is delivered in fiber, use the fiber input.  If not, stay  with the copper based system.  going back and forth does more harm than good.    
Converting from 230v to 110 v
I agree with Eric.  I answered for an amp, which is much more challenging service.  
Converting from 230v to 110 v
I run a euro amp on US 230V (stoves, dryers, ovens etc are wired for 230V). Using a transformer can be more of an issue.  They can hum.  You should buy one that is quite oversized to support any amp power requirements.  I'd get at least 1KW, if n... 
PS Audio Nuwave DSD DAC
google found manual for DSD https://data.heimkinowelt.at/d/bed/p/ps-audio-nuwave-dsd-bed-a31369.pdf   and DAC https://cdn.shopify.com/s/files/1/0672/2283/1394/files/NuWave-DAC-Owners-Manual-V2.pdf?v=1668767777  
Recommendations for a vacum tube tester
not gonna happen for that price.  
My experience with Kinki warranty
I have kinki amp. Nothing but great communication.  Not sure why you didn't go to them in the first place.  Didn't you buy it direct?  I did.  
Seriously though, maybe the best tweak is exercise?
I've been an endurance athlete pretty much all my adult life.  I did triathlons and distance races in my 30's and 40s.  Marathon was my best distance.  Now that I'm older I'm dabbling in ultramarathons.  I work 4 days a week and any day I don't wo... 
Legacy XD series for tube amplifier thoughts
I've thought the same thing.  Report back your findings.  
Rhodium plated audio grade wall socket
Rhodium is not a great conductor but sounds exotic and marketing types love to brag about it.