🔌 Delayed High-Voltage Power Supply Module with Pre-Charge

This delayed high-voltage power supply module with pre-charge is designed to provide a gradually rising high-voltage DC, protecting the cathodes of electronic tubes while eliminating switch-on noise when powering tube amplifiers.

It easily connects to the high-voltage secondary of the transformer (single secondary or center-tapped) and requires no additional power source.
The module delays the application of high voltage to the amplifier circuits, giving the tubes time to warm up. A low-voltage pre-charge ensures a smooth and safe power-up.

⚙️ Key Features

• Compact dimensions: 90 × 50 × 20 mm
• AC input voltage: 150 to 450 V (≈ 200 to 650 V rectified and filtered)
• Maximum switched current: 2 A
• Nominal delay: 40 to 80 s, adjustable via 10-turn potentiometer
• Power consumption: < 10 mA on high voltage
• Easy connection: 2 input wires / 2 output wires, no amplifier modification required
• LED indicator: lights when high voltage is applied
• Compatible with center-tapped HV secondaries

🔒 Advantages

• Protects tube cathodes from inrush currents at startup
• Eliminates switch-on noise and sparks (no mechanical relay)
• Very high reliability: no wear components, silent operation
• Near-zero power consumption and no heating

🛠️ Typical Applications

• Tube amplifiers and preamplifiers
• Experimental projects and high-voltage test benches
• Circuits requiring gradual and silent high-voltage startup