The Helvia 4120CA PA power amplifier features four independent channels, each with a line transformer and 120 W of power on a 100 V line. Each channel can operate on 70/100 V constant-voltage lines or at low impedance (4–16 Ω), while the HPF has a cutoff frequency of 400 Hz.

The channels feature volume controls, VU-meter and clip LED indicators, and rear-panel gain controls. The balanced inputs and outputs connect via XLR, while the power outputs use Phoenix (Euroblock) connectors. Features include power-on muting, signal limiting, thermal protection, and current limiting. The fan adjusts its speed according to the internal temperature.

• Type: PA power amplifier
• Channels: 4
• Power per channel at 100 V: 120 W
• Output lines: 70/100 V and 4–16 Ω
• HPF: 400 Hz cutoff frequency
• Frequency response: 80–20 kHz or 400 Hz–20 kHz
• Damping factor: >300 at 100 Hz
• THD: <0.1% at 1 W and 1 m
• Inputs and outputs: Balanced XLR
• Power output connections: Phoenix (Euroblock)
• Cooling: Fan with speed control based on internal temperature
• Rack format: 19″, 2U
• Width: 484 mm
• Height: 88 mm
• Depth: 400 mm
• Weight: 13.5 kg