Hi everyone! A guy in the ru input lag community noticed a massive improvement after rebuilding an old, oxidized aluminum-to-copper wire splice in his apartment. He noted that his neutral-to-ground voltage dropped from 1–3V down to 0.5–1V. I discussed the physics behind this with an AI, and it suggested an interesting power delivery solution. I can't test it myself right now due to a lack of equipment, but maybe some of you can.
The Core Problem: Dirty Neutral and Neighbor Noise
In reality, the main neutral line of a residential building is flooded with heavy high-frequency (HF) electromagnetic noise generated by hundreds of neighbors (inverter A/Cs, induction cooktops, elevator variable-frequency drives). Because of this, the neutral-to-ground potential constantly fluctuates. As a result, the Y-capacitor inside the PC power supply on the neutral side unintentionally conducts in reverse: it allows all this neighboring HF garbage to bleed directly onto the metal PC chassis.
Since the PC chassis is directly tied to the motherboard's signal ground (GND), this HF noise introduces severe phase noise (jitter) into the motherboard's PLL clock generators and degrades the reference voltage of the mouse sensor's internal ADC. This electrical instability causes hardware-level timing drift during interrupt handling and coordinate processing, which translates into that notorious "heavy/muddy" mouse tracking feeling.
What People Usually Get Wrong
Typically, people just plug their PC directly into a standard 1:1 isolation transformer, leaving the secondary grid fully "floating" (where both output lines are completely isolated and have an undefined, floating potential relative to earth). However, consumer ATX power supplies are strictly designed and safety-certified for asymmetrical grids (a distinct Line and Neutral). Running them in a floating mode alters the intended path for common-mode noise dissipation, meaning the line noise keeps circulating inside the system instead of being effectively suppressed.
The Solution: Forcing a Local Reference Zero
The solution is to force-create a local reference zero:
- Get a true 1:1 isolation transformer (1.0–1.6 kVA) with an electrostatic shield between the primary and secondary windings.
- Connect the "dirty" wall ground ONLY to the external metal chassis of the transformer itself (for fire safety).
- The most important part: Take one of the two output wires from the secondary winding of the transformer and physically bond it to a clean, dedicated personal ground.
By doing this, we explicitly pin this wire to the ground potential, turning it into a dedicated, crystal-clear
reference zero (strictly 0.00V). The second wire automatically becomes a clean, isolated phase (Line). This brings three perfect lines to your PC power strip, completely isolated from neighboring voltage sags and line noise.
What This Achieves in Practice
This completely separates the PC from kilometers of dirty residential neutral cabling. The input Y-capacitor on the neutral side completely calms down because the potential difference between the new neutral and the PC chassis becomes exactly zero. The PSU filter operates at maximum efficiency, instantly dumping the PSU's own internal switching noise to ground. The motherboard's PLL and the mouse sensor's signal ground are cleared of high-frequency jitter, yielding the cleanest possible "raw input" for the mouse.
The only catch for me right now is that I need the isolation transformer and a solid personal ground setup, which I currently lack.
Has anyone here tried using an isolation transformer in this specific configuration—grounding one leg of the secondary winding to establish a reference zero, rather than just running it in a standard "floating" mode?
