The SPL Pre One is a dual-channel microphone and instrument preamplifier that combines classic Class A discrete technology with SPL’s proprietary 120V VOLTAiR high-voltage rail system. Each of the two channels offers both a balanced microphone input and a front-panel instrument input. Microphone and instrument inputs are selected using a toggle switch on the front panel. The instrument inputs are designed to handle high-impedance signals and are routed through the same fully discrete preamp stage used for microphones.
Gain for each channel is adjustable from +10 dB to +65 dB via a 41-position detented potentiometer, ensuring precise and repeatable settings. Each channel is equipped with peak LEDs to help avoid signal clipping during recording. A -20 dB pad switch provides additional headroom for recording particularly loud sources. The switchable high-pass filter offers three frequency options, 60 Hz, 120 Hz, and 240 Hz, to reduce low-end rumble or proximity effect. A phase reverse switch is included on each channel to correct polarity issues during multi-microphone recordings.
A standout feature of the SPL Pre One is its switchable input impedance, with four selectable values: 1.2 kΩ, 2.4 kΩ, 5 kΩ, and 10 kΩ. This flexibility allows precise matching of the preamp to different microphone types, ensuring optimal frequency response and transient behaviour. Phantom power is individually switchable for each microphone input.
Each channel provides two balanced outputs, XLR and TRS, located on the rear panel, supporting seamless integration into a variety of recording setups. The 120V VOLTAiR technology at the heart of the SPL Pre One ensures extremely low noise, high headroom, and maximum sonic integrity across the full dynamic range. The unit is powered by an internal linear power supply with a toroidal transformer and features an all-metal 2U rackmount chassis with a precisely milled aluminium front panel.
Designed and manufactured in Germany, the SPL Pre One is built for professional studios that demand top-tier performance, versatility, and sonic accuracy in both microphone and instrument recording applications.
Features
- Two-channel microphone and instrument preamplifier
- Fully discrete Class A transistor design
- VOLTAiR 120V high-voltage rail technology
- Balanced XLR mic input and front-panel instrument input per channel
- Switchable input impedance: 1.2 kΩ, 2.4 kΩ, 5 kΩ, 10 kΩ
- Selectable high-pass filter: 60 Hz, 120 Hz, 240 Hz
- -20 dB pad switch per channel
- Phase reverse switch per channel
- 41-position detented gain control: +10 dB to +65 dB
- Peak LED indicators per channel
- Switchable +48V phantom power
- Balanced XLR and TRS outputs per channel
- Internal linear power supply with toroidal transformer
- Solid metal chassis with aluminium front panel
- Designed and manufactured in Germany
