Engineered for precision LDR control

The ePot.V4 employs precision linear analog op amps to control LDR resistance. Because such devices are inherently sensitive to power supply noise, the availability of clean, low-noise 5 volt power, can influence the delivered sound quality from the ePot.V4.

The LPS5.V4 is a non-compromise, 5-volt, 1-amp linear power supply explicitly over-engineered to provide robust low noise power. It treats the ePot.V4's precision current controller not as a simple accessory, but as the literal foundation of regulating the volume of your audio.

Really low-noise 5 volt power

When under a fully rated 1 amp load, the LPS5.V4 delivers dead quiet 5 volt power with under 100 microvolts (uV) RMS ripple.

Dual voltage mains

The LPS5.V4 is a classic linear 5 volt DC regulated power supply that runs off either 120 or 240 VAC mains power as determined by a pair of simple jumpers.

Low noise Schottky diodes reduce high frequency rectification noise which is further suppressed through the use of snubbers on each rectifier. Power is deliberately routed through multiple ground plane islands to further isolate noise. A first order filter further mitigates noise before being passed through a final linear regulation stage equipped with a finned heat sink.

25 VA semi-toroidal transformer with massive headroom

While the epot.v4 controller board has a nominal power demand of well under 5 VA, the LPS5.V4 is equipped with a massive 25 VA semi-toroidal transformer. Over-specifying the magnetic core by 500% provides distinct sonic advantages:

Zero magnetic saturation: Operating far below its threshold eliminates core saturation, preventing the transformer from radiating 60 Hz hum or mechanical vibrations.

Ultra-low internal DC resistance (DCR): Dropping the source impedance of the AC supply guarantees that sudden multi-channel LDR current adjustments occur with zero voltage sag across the circuit.

Low stray fields: The flat, semi-toroidal geometry restricts magnetic flux lines tightly within the core, ensuring radiated AC field noise cannot bleed into the LDR control or signal paths.

Quiet rectification: Schottky diodes & snubber networks

Standard silicon rectifiers suffer from "reverse recovery time," snapping shut violently and injecting high-frequency electromagnetic interference (EMI) back into the DC rails. This high-frequency edge hash can easily bypass standard regulators and induce micro-ripple into the LDR control lines.

The LPS5.V4 eliminates this vulnerability by using high-speed Schottky diodes. With near-zero reverse recovery time, they transition from AC to DC silently. Each diode is paired with a tuned RC snubber network to dampen any parasitic high-frequency ringing between the transformer's leakage inductance and the diode capacitance. The result is an incredibly smooth, artifact-free DC raw feed.

High-transient regulation via the LM1086

Following a robust, single-stage reservoir filter that flattens bulk ripple, voltage is pinned by the high-performance LM1086 5 volt linear regulator with a 50% current margin above the 1 amp rating of the LPS5.

Unlike generic regulators, the LM1086 features exceptional line and load regulation alongside superior ripple rejection. Most importantly, its lighting-fast transient response ensures that when the controller updates the volume setting and alters the current draw across multiple LDR channels, the output voltage remains perfectly flat. This prevents any crosstalk or dynamic current sagging between left and right channel LDR elements, locking in precise, predictable resistance curves.

Segmented ground typography

The cleanest components are useless without proper trace routing. The LPS5.V4 utilizes an advanced PCB layout featuring multiple ground islands connected through narrow copper chokepoints.

This topographical isolation separates the noisy AC charging currents at the rectifier stage from the ultra-clean reference ground of the LT1085 regulator. By confining ground return currents to their local loops, the LPS5.V4 keeps the control reference line unpolluted. This absolute ground stability allows the epot.v4 to maintain rock-solid current matching across all LDR channels, yielding a deep, holographic soundstage and accurate channel tracking.

Robust hardware

Everything comes mounted on a heavy duty 2.7 x 5.5 inch PCB board with 5 mounting holes. The power supply runs cool and barely breaks a sweat.

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