SPL AUDIO Crescendo duo Dual-Channel Microphone Preamplifier with 120V technology
Home / SPL AUDIO Crescendo duo Dual-Channel Microphone Preamplifier with 120V technology
Product Overview
The High-Voltage Analog Standard for Transparent Stereophonic Tracking
The SPL Crescendo duo addresses the primary bottleneck of traditional studio preamplifiers: internal clipping and transient compression caused by low-voltage design boundaries. While standard high-end preamps squash high-energy audio peaks or introduce harmonic distortion when pushed, the Crescendo duo operates on an unprecedented high-voltage internal power grid. Built specifically for stereo overheads, classical ensemble arrays, acoustic instruments, and demanding vocal tracking, this dual-channel masterwork captures the raw, unfiltered reality of a performance with three-dimensional depth and zero sonic alteration.
Product Description
Proprietary 120V VOLTAiR Technology:
The engineering foundation of the Crescendo duo is SPL’s exclusive VOLTAiR 120V operational amplifier technology. While standard professional audio components operate on a limited $\pm$15V or $\pm$18V internal grid, VOLTAiR circuits run at a massive $\pm$60V DC. This four-fold increase in internal voltage yields an exceptional structural ceiling. It maximizes the dynamic range to a staggering 141.4 dB, drives the self-noise floor down to near-infinite silence, and eliminates thermal distortion. High-transient signals—such as the sharp crack of a snare drum or the sudden fortissimo of an opera singer—pass through with absolute transient velocity, preserving pristine micro-details exactly as they were captured in the room.
Completely Discrete Class-A Circuitry:
The signal path of the Crescendo duo is purely discrete and runs in full Class-A mode. The differential input stage utilizes precisely matched pairs of high-voltage transistors, entirely bypassing mass-produced integrated circuit (IC) op-amps that add phase shift or graininess. The output stage functions as a current-amplifying class-A emitter follower, maintaining incredibly low output impedance ($75\ \Omega$) to comfortably drive ultra-long studio cable runs without high-frequency signal degradation. This design guarantees an ultra-wide frequency tracking response spanning from 20 Hz up to 100 kHz with an linear phase response.
Surgical Control Interface Per Channel:
The front panel provides independent, stepped, and continuously variable controls for both channels, allowing for accurate stereo matching:
Mic Gain Switch: A heavy-duty, 12-position rotary switch that increments gain from +18 dB to +70 dB in precise 4 dB steps.
Fine Gain Control: A center-detented potentiometer that adds or subtracts up to $\pm$6 dB of fine volume correction, allowing for fluid, micro-precise micro-level tracking.
Output Level Control: An independent output pad that lets you attenuate the signal before it reaches your AD converters, allowing you to drive the preamplifier hot for transient speed without clipping your DAW inputs.
Professional Tool Integration Rig:
Each channel is equipped with a dedicated suite of hardware diagnostic toggles driven by gold-plated relays:
Individual 48V Phantom Power: Supplies clean, regulated power to demanding condenser microphones.
Phase Inversion Toggle: Instantly flips signal polarity by 180° to fix phase cancellation when multi-miking a single source.
High-Pass Filter: A 6 dB/octave roll-off filter centered at 50 Hz to cleanly eliminate low-end room rumble, HVAC noise, or structural vibrations.
Pad Switch: Attenuates the input signal by -20 dB, allowing the preamplifier to accept hot line-level instruments or extreme transient sources without overloading the discrete input stages.
Key Features
120V VOLTAiR Power Rails: Flagship high-voltage audio operating rails ($\pm$60V DC) yield an incredible 141.4 dB dynamic range with near-infinite signal headroom.
True Dual-Mono Class-A Layout: Completely discrete transistor architecture runs in pure Class-A to eliminate crossover distortion and deliver absolute sonic transparency.
Stepped Precision Gain Controls: 12-position master switches coupled with fine-gain potentiometers ensure perfect channel matching for stereo recording arrays.
Input and Output VU Metering: Dual mechanical VU meters display incoming or outgoing signal levels accurately, equipped with a -10 dB level reduction pad for tracking hot signals.
High-Voltage Line Headroom: Input stage handles demanding professional line and microphone signals effortlessly, tracking transients with zero clipping.
Dedicated Variable Output Pads: Front-panel knobs let you adjust the final level going into your digital audio converters without sacrificing input stage performance.
Handmade in Germany: Proudly hand-assembled and quality-calibrated in Germany, arriving backed by SPL’s world-class pro-audio engineering.
