Thank you Galen
From my DB board, I’ve run a 6mm twin & earth cable on a 20A breaker to a dedicated plug for my HiFi. My P20 was always happy with it using BHK 300’s, BHK Pe, PST Transport, Samsung 85 inch TV and DSII DAC.
I recall when I added a Rose RS150B the P20 also seem not to like it (overheated), but at the time I wrote it off to a loose connection on one of my LI batteries. In hindsight, I do not think so any more.
Then I moved my room from “tunnel” to “landscape”. As I did not want to move the power plug, I used a professionally made up extension cable. Poper grade 3-core 2.5mm core, with the best SA plug I could find and a proper audiophile IEC on the other side. With this configuration my old system was quite happy.
When the Aurender stuff arrived, the problems started. I called my electrician, who blamed the plug outlet and replaced it, properly testing it on both ends. My HiFi friend blamed the IEC end, which he thought felt somewhat loose when plugged into the P20. I replaced that with a decent Transparent IEC. With the electrician still present, we tested the cable with a proper draw. So I can say with confidence that we eliminated everything from DB board to P20 as a possible contributing factor. And the problem remained, the P20 kept going into protection mode - just with the AP20 on idle.
But: What you say about the PF makes sense. I’m not so much technically minded. I recall that many years ago, PSA had an ampifier with a switch mode PSU that used to create havoc on the power plants of the time, due to this problem. But, the AP20 uses 6 Toroidals, not switch mode PSU’s: 2 x 400VA for the Eigentakt modules; 2x50W for the DAC; 1x50W for the CPU and 1 x 25W for the FPGA. According to Gemini, 975VA total.
Gemini furthermore says:
The Aurender AP20 overheats your P20 because its massive 975VA linear power supply operates at a low power factor. Instead of drawing power smoothly, it pulls current in violent, out-of-phase spikes at the peaks of the AC wave. The P20 acts as a literal amplifier to recreate your power; fighting this highly reactive, inductive load forces its output transistors to dissipate massive amounts of energy as pure heat, triggering thermal shutdown even when the Aurender is just idling.
The Aurender NH10 blows the fuse due to massive inrush current upon startup. Because its specialized audio-grade toroidal transformer and oversized capacitor banks are completely empty when cold, they act as an instantaneous short circuit for a fraction of a second. This massive initial current surge hits the P20’s fast-reacting output rail like an electrical sledgehammer, instantly overloading and snapping the fuse before the hub can initialize.