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Useful in connecting a guitar, keyboard, bass—or indeed, any other instrument with a 1/4" output—to an XLR input, the Telefunken TDA-1 is a single-channel DI box.


The unit utilizes active, discrete class-A FET circuitry which, when coupled with components such as an OEP/Carnhill transformer, helps you to achieve a tone with clean, high headroom and a warm, saturated timbre. The TD-1 sports other constructive features which recommend it heartily; for instance, its printed circuit boards are assembled by hand with through-hole components; this ensures both security and reliability in its connection points. Additionally, all circuit traces have been gold-plated to bolster conductivity, while the circuit itself has been encased in an extruded aluminum enclosure. As such, you'll find it more than suitable for the wear and tear of gigging.


The DI box provides a frequency range of 20 Hz to 70 kHz, giving you both a -15 dB pad and a ground lift, should you encounter noise issues. A 1/4" pass-through output is also provided, making this unit very handy in the studio; for instance, you could take a DI off an electric guitar and use the 1/4" pass-through to plug into an amplifier. In this manner, you can record both the sound of an amped guitar and a clean, dry guitar, giving yourself options in the mix. This is but one of the many uses you may find for this feature.The circuit runs off of 48 VDC phantom power supplied from a console or recording interface, and an LED indicates when phantom power has been instantiated. Please note that if phantom power isn't running, you'll only get a substantially lower, weaker signal out of your instrument.

The Features

Custom-wound OEP/Carnhill transformer, made in the UK

Rugged aluminum construction

Class-A discrete FET circuitry

Recessed switches and connectors for protection

+48V phantom powered with LED indicator

-15 dB pad switch

Ground lift switch

100% through-hole components

Amphenol connectors

WIMA, Nichicon, and Panasonic capacitors

1% 1/4W metal film resistors


Telefunken TDA-1 Active Mono Direct Box

  • Telefunken TDA-1 Active Mono Direct Box
  • Active mono FET direct box utilizing top quality components
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