I'm too lazy to write another post, so copy and paste from sister thread qutest which needs a 5V alternative power source much more:
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I hope I'm not intruding. I opened up Pandora's Box about Mains back in the day on Chord threads. I'm just making a drive-by post then back in September a bit when I have more energy. We love our drive-bys in Los Angeles.
I've been wanting to build a Off-Mains USB Charger for my Hugo₂ for quite a while.
Problem: My Hugo₂ and USB optical cable was always connected to Mains power via a USB charging port. It's a loophole for noise to get in the chain.
So I wanted to cut off from Mains, but there are no solutions available. My Hugo₂ needs to be charged for 24 hours before entering "Intelligent Desktop Mode", so batteries for charging will not work as it would reset "Intelligent Desktop Mode". The wall outlet charger supplied with the Hugo₂ will not work since it is Mains.
Solution: UltraCapacitors to the rescue. My Hugo₂ has now been in "Intelligent Desktop Mode" for 3 straight days charged by UltraCapacitors with minimal Mains involvement. Mains is needed for a few minutes to charge the Ultracapacitors about 6 times over 24 hours.
Here is the USB Solid Core cable I created with 3M Heat Shrink to be used with the UltraCapacitor:
I believe Solid Core wiring to be impenetrable since it's completely solid. So noise getting into traditional wiring was a thing, noise getting into solid core wiring I don't believe to be a thing. 12 gauge from PCB to Ultra-capacitors. 22 gauge USB from PCB to Hugo₂ or Ultra-Capacitors to USB optical @5V.
Rob Watts runs his own Solid Core Recipe for speaker cables to B&W Diamonds. He has an unlimited budget, but yet chooses Solid Core. Hmmm? Here, it's for power use as I already have the best CIEM cable one can acquire with WBT RCA OUT. So presently, I have the world's best 5V Power Supply, world's best CIEM cable and world's best Toslink source so basically world's best CIEM chain.
3000 Farads, Dynamic Amps up to 1000A, < 0.5 milliohms so very close to bare metal low latency performance as you can get.
For example, Hugo₂ output impedance is outstanding and you know you are getting quality:
So it turned out to be a successful Summer Project. I was really concerned this wouldn't work as the Ultracapacitor and Hugo₂ need to play nice with one another. I'm hoping to get 21 straight days of "Intelligent Desktop Mode".
Now I have to research Qutest power input if it's the same as the Hugo₂. I'm really rusty at this hobby so please forgive not knowing the power input.
I really think battery packs are for charging only, not to power audio. There's too much down-conversion from 13.2V to 12V or up-conversion 3.3V to 5V. If there is not conversion involved that's okay. For example, I've been running this since the start of COVID.
You can run it @ 4 batteries @ 13.2V (4 X 3.3V) or 5 batteries @ 16.5V (5 X 3.3V):
It has a 2.5mm DC plug with Solid Core Silver wiring. Notice the stiffness. So this should be able power a TT₂ or HMS.
Now, I recommend just going straight to Ultra-Capacitors and bypassing batteries altogether, Ultra-Capacitors should last a good decade. Batteries are too finicky.
These are highly-regarded battle-tested UK Ultra-capacitors that you will find all over UK International Airports @ Command And Control and Mission Critical UPS devices so it's super high quality. If Airports can rely on UltraCapacitors, your home HiFi gear should be okay too.