Class-A FET Clarity Meets British Transformer Character in True Stereo
When managing low-output stereo instruments or multiple delicate line-level tracks in modern live sound and studio production, maintaining an expansive, phase-coherent stereo image is critical. The Telefunken TDA-2 Dual Active Direct Box addresses this exact acoustic need, packing two premium, completely isolated active DI channels into a single compact footprint. Because it features an active architecture on both channels, it extracts the maximum dynamic range, transient bite, and harmonic nuance from your instruments without loading down electronics or altering your natural tone.
The secret behind the TDA-2’s stunning sonic open-endedness is its dual-stage engine. The incoming instrument signals are first greeted by premium, hand-selected Field Effect Transistor (FET) circuits that behave with tube-like smoothness and immense input impedance ($1\text{ M}\Omega$). These pristine signals are then balanced and colored beautifully by dual custom-wound UK-made OEP/Carnhill transformers. Powered simply by standard +48V phantom power from your mixing console or audio interface, the TDA-2 provides a rich, uncompressed, "mix-ready" stereo field that cuts through any live or studio environment.
Product Description
Dual High-Impedance Class-A FET Circuits & OEP/Carnhill Output Engines:
The acoustic identity of the TDA-2 is anchored by its meticulous component matching across both channels. Stereo instruments can lose their high-frequency sparkle and low-end definition when connected to low-impedance inputs. The TDA-2 solves this by presenting a massive $1\text{ M}\Omega$ input impedance per channel via its discrete Class-A FET circuits, allowing your pickups to breathe and perform exactly as the instrument builder intended. This active stage delivers an ultra-wide, breathtaking frequency response from 20 Hz all the way up to 70 kHz.
Following the FET input buffers, the signals pass through dual custom-spec OEP/Carnhill transformer cores. These legendary British-made components provide flawless isolation and impedance matching while stepping down your instrument lines into low-impedance ($200\text{ }\Omega$) mic-level outputs. The transformers saturate musically when pushed, adding a professional weight and subtle warmth to the lower-mid frequencies that makes direct tracking lines sound incredibly solid, deep, and multi-dimensional.
Bulletproof Hardware Architecture and Stage Protection:
The exterior of the TDA-2 is built like a tank to withstand the punishing environment of professional concert touring. The enclosure is constructed from heavy-duty extruded aluminum, eliminating body flex and shielding the delicate internal FET electronics against stray electromagnetic fields (EMI) and radio frequency interference (RFI). All toggle switches are deeply recessed within the chassis walls, ensuring they cannot be accidentally flipped or snapped off when packed into road cases or stepped on mid-performance.
Every single connection point on the TDA-2 utilizes top-tier hardware components. The instrument inputs and parallel through-put jacks are genuine, heavy-duty 1/4" metal-threaded connectors, while the balanced outputs feature premium 3-pin Neutrik XLR connectors with 24K gold-plated pins. This gold-on-gold contact ensures maximum electrical conductivity and stops corrosion or oxidation from degrading your sound over decades of heavy live and studio use.
Advanced Gain Management and Hum Isolation per Channel:
To handle the unpredictable signal levels found in modern stage setups, each channel of the TDA-2 is equipped with an independent, high-grade -15 dB attenuation pad. Engaging this switch drops the incoming gain, allowing the active circuitry to comfortably accept hot line-level outputs from keyboards, DJ mixers, or digital audio interfaces without clipping or distorting the internal FET input stage.
Additionally, the unit features independent Ground Lift switches for Channel 1 and Channel 2. When dealing with complex stage power distribution networks that create nasty background hums and 60 Hz buzzes, activating the ground lift isolates the input and output grounds. This breaks dangerous loop circuits instantly, restoring a dead-silent noise floor to your signal path without sacrificing high-frequency detail or stereo separation.
Key Features
STEREO OR DUAL MONO TRACKING: Perfect for stereo keyboards, acoustic-electric instruments, electronic drums, or running two completely separate mono instruments.
ACTIVE CLASS-A FET CIRCUITRY: High-impedance active buffers preserve full dynamic range and transient detail without loading down passive pickups.
DUAL BRITISH OEP/Carnhill TRANSFORMERS: Driven by two premium, custom-wound OEP/Carnhill output transformers (UK) for rich analog weight, warmth, and absolute isolation.
EXTENDED FREQUENCY SPECTRUM: Ultra-wide 20 Hz to 70 kHz response captures pristine high-end shimmer and deep sub-bass frequencies perfectly.
INDEPENDENT +48V PHANTOM POWERED: Standard active design runs efficiently off +48V phantom power per channel with high-visibility LED power indicators.
RECESSED TOGGLE ARCHITECTURE: All utility switches are deeply recessed into the casing to prevent physical damage or accidental activation on stage.
GENUINE NEUTRIK XLR OUTPUTS: Dual balanced 3-pin male Neutrik XLR outs featuring 24K gold-plated pins for lossless connectivity and corrosion resistance.
SELECTABLE -15 dB ATTENUATION PADS: Independent high-grade pads drop incoming gain to prevent overloading when connected to hot electronic or line-level sources.
TWO GROUND LIFT SWITCHES: Safely decouple pin-1 from each circuit to safely break ground loops independently and eliminate system buzz, hum, and hiss.
1/4" PARALLEL THRU JACKS: Allow you to send an uncolored dry signal simultaneously to on-stage amplifiers or monitors while routing the balanced outs to FOH.
Technical Specifications
Feature
Specification
DI Box Type
Dual / Stereo Active Direct Box
Input Circuitry
2 x Discrete Class-A FET Input Stages
Output Transformer Cores
2 x Custom-Wound British OEP/Carnhill Transformers
Number of Channels
2 (Completely Isolated)
Frequency Response
20 Hz – 70 kHz ($\pm$2 dB)
Input Impedance
1 M$\Omega$ per channel (Active Instrument Buffer)
Output Impedance
200 $\Omega$ per channel (Balanced Mic Level)
Total Harmonic Distortion
< 0.015% (Typical at 1 kHz, 0 dBu Input)
Power Requirement
+48V Phantom Power per channel (Standard Mic Preamp Link)
