CSI-1830 Power Supply, for example

Nissei CSI-1830
Nissei CSI-1830 Linear Power Supply (30A) with Analog Meters The Nissei CSI-1830 is a top-of-the-line, classic linear (transformer-based) power supply designed for the most demanding ham radio operators and electronics workshops.
Unlike modern switching power supplies, it features a traditional, robust design with a heavy-duty transformer, which provides a perfectly clean, stable DC output with zero high-frequency noise and electrical interference.
It is the ideal choice for powering sensitive HF/VHF radios, test benches, and laboratory equipment.
Traditional linear design: Maximum filtering and output voltage stability without any traces of switching noise that could interfere with radio wave reception. The
output voltage can be continuously adjusted using a rotary control within a range of 1.5 to 15 V DC.
The power supply effortlessly delivers a continuous current of 20 A and can handle short-term peaks of up to 30 A.
Large backlit meters (voltmeter and ammeter) on the front panel ensure immediate visual monitoring of the power supply status.
Robust chassis for demanding applications: Heavy-duty construction with robust cooling for safe, long-term operation under load.

Technical Specifications
Power Supply Type: Linear (transformer-based)
Input Voltage: 230 V AC / 50 Hz
Output Voltage: 1.5 – 15.0 V DC (continuously adjustable)
Continuous current: 20 A; Peak current (max.): 30 A
; Meters: 2x analog meters (V / A)
; Front-panel fuse, overload and short-circuit
protection