SPL AUDIO Pre One Dual-Channel Microphone Preamplifier
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Product Overview
The Definitive Standard for Pure, High-Headroom Amplification
The SPL Pre One is designed as the ultimate solution for audio engineers and producers who demand absolute acoustic transparency from their front-end hardware. Instead of adding heavy tube saturation or color, the Pre One focuses on amplifying the true, unaltered character of your microphones and instruments. Hand-built with discrete components, this dual-channel workhorse provides a massive gain layout and extreme dynamic headroom, making it a stellar choice for tracking everything from delicate acoustic ribbons to high-gain transient drum arrays.
The internal layout of the Pre One avoids generic, off-the-shelf integrated circuits in favor of a fully discrete analog circuit design. Each channel features a high-spec instrumentation preamplifier configuration optimized for ultra-low noise tracking and lightning-fast transient capture. This open, fast-responding architecture delivers up to +68 dB of clean, uncolored analog gain, ensuring that even low-output passive ribbon microphones and heavy dynamic broadcast mics run completely silent without requiring external signal boosters.
Variable Low-Cut Filters and Comprehensive Channel Tools:
To handle unpredictable low-end acoustic clutter, the Pre One breaks away from standard rigid filter switches by providing a fully variable High-Pass Filter knob on each channel. This sweepable control lets you roll off frequencies anywhere from 10 Hz up to 200 Hz with a smooth 6 dB/octave slope, allowing you to target and eliminate room rumble or muddy vocal proximity effects with surgical precision. Each channel is fully loaded with independent hardware toggles for 48V Phantom Power, a 20 dB Attenuation Pad, and Phase Inversion (Pol).
Hi-Z Instrument Inputs and Pure-Analog Signal Path:
Beyond world-class microphone tracking, the Pre One doubles as an elite DI box. The front panel features two independent 1/4-inch Hi-Z (High-Impedance) inputs, allowing singer-songwriters and multi-instrumentalists to plug electric guitars, active basses, or vintage synthesizers directly into the discrete preamp stage. The internal power grid steps up incoming power to generate a massive internal voltage ceiling, allowing the unit to handle high-level line signals up to +22.5 dBu without causing internal clip distortion.
Tour-Grade Desktop Casing and Visual Feedback:
Housed in a rugged, low-profile desktop enclosure with a thick, premium aluminum front panel, the Pre One is built to sit beautifully on your studio workspace or endure heavy mobile recording tracking. The front layout provides instant visual tracking via dedicated Signal and OVR (Overload) LEDs for each channel, warning you immediately if your converters are risking clipping. The rear panel features professional, gold-plated balanced XLR inputs and outputs alongside a line of balanced TRS outputs to guarantee a completely secure, noise-free connection to your audio interface or mixing desk.
Key Features
Dual Discrete Preamplifiers: Two fully independent channels utilizing premium discrete components to deliver an incredibly open, transparent soundstage.
Up to +68 dB of Clean Gain: Massive power reserves easily drive demanding low-output microphones with zero background hiss.
Continuously Variable High-Pass Filter: Sweepable 10 Hz to 200 Hz low-cut control allows you to tailor the low-end cutoff smoothly on any tracking source.
Front-Panel Hi-Z Instrument Inputs: High-impedance DI inputs allow direct, pristine tracking for electric guitars, basses, and keys.
Dedicated Channel Tool Suite: Independent front-panel hardware toggles for 48V phantom power, a -20 dB pad, and phase polarity inversion per channel.
High-Voltage Internal Headroom: Sophisticated internal voltage architecture supports line levels up to +22.5 dBu to prevent transient clipping.
Signal and Overload LED Indicators: Instantaneous hardware visual feedback keeps your gain staging perfectly optimized during loud tracking sessions.
Technical Specifications
Feature
Specification
Device Type
Dual-Channel Discrete Analog Microphone Preamplifier & DI
Preamplifier Circuitry
Discrete Instrumentation Amplifier Topology
Maximum Microphone Gain
+68 dB (Extremely clean, high-spec gain profile)
Maximum Hi-Z/Line Gain
+48 dB
Analog Input Channels
2 x XLR Balanced (Mic) / 2 x 1/4" TS Unbalanced (Front-panel Hi-Z)
Analog Output Channels
2 x XLR Balanced / 2 x 1/4" TRS Balanced
Frequency Range
10 Hz to 200 kHz (-3 dB) — Ultra-wide linear response
High-Pass Filter (Low Cut)
Continuously variable from 10 Hz to 200 Hz (6 dB/octave slope)
Attenuation Pad
-20 dB (Independent switch per channel)
Total Harmonic Distortion (THD+N)
0.003% (at 30 dB Gain, 1 kHz) — Ultra-low distortion path
Input Impedance
10 kOhms (Microphone) / 1 MOhms (Hi-Z Instrument)
Maximum Input & Output Level
+22.5 dBu (Providing massive pro-studio headroom)
Dimensions (W x H x D)
210 x 49.6 x 220 mm (8.23 x 1.95 x 8.66 inches)
Unit Weight
1.48 kg (3.26 lbs)
What’s Included in the Box
1 x SPL AUDIO Pre One Dual-Channel Preamplifier Unit
1 x 12V DC / 1.5A External Switching Power Supply Adapter
1 x Set of Adhesive Rubber Desktop Isolation Feet
1 x Official User Operations Manual & Gain Calibration Guide
