Telefunken TDA-1 / Mono Active Direct Box

The TDA circuit employs discrete Class-A FET circuitry coupled with a high quality transformer that provides the perfect balance between clean, high headroom performance and warm, saturated tone with vibe. While some direct boxes focus on providing sterile, ultra-clean gain, they often leave the instrument devoid of any soul or character. Conversely, some DI’s artificially hype too much low-end and overemphasize harmonic distortion, resulting in a tubby and undefined output. The Telefunken active DI avoids these common design pitfalls and delivers a new standard in reliability and performance for direct boxes. The heart of the design is a custom-wound output transformer by OEP/Carnhill, made in the UK. The circuit board features gold plated traces and is entirely hand-assembled with through-hole components, providing more secure and reliable connections than typical surface mount circuitry. The frequency response of the circuit is ± 1dB from 20 Hz to 50 kHz, with extremely low distortion and self-noise. Each individual unit is manually tuned by hand for the lowest distortion figure possible. High input impedance prevents the loading down of passive pickups. This careful attention to detail and high quality component choices results in a direct box with a harmonically rich low end and a detailed, open high-end clarity.