Telefunken TDA-1
Sonic Characteristic
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.
Circuit Design
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.
Construction
The circuit is housed in an extremely durable extruded aluminum enclosure with recessed switches and connectors. This rugged construction is virtually indestructible, able to easily withstand the wear and tear of gigging. Each channel features two heavy duty metal toggle switches to engage a -15 dB pad and ground lift. The circuit is powered from standard +48V phantom power with an LED indicating when it is powered. The TDA-2 unit features two independent DI channels with separate controls, giving you the ability to run two instruments through one footprint on stage or in the studio.
Key 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
Technical Specifications
- Channels: 1 (TDA-1), 2 (TDA-2)
- Transformer Custom-Wound OEP/Carnhill Transformer
- Frequency Range 20 Hz – 50 kHz, ±1 dB
- Noise -116 dBV (unweighted)
- Input Impedance > 30kΩ
- Output Impedance < 250Ω
- Power Requirement +48 VDC Phantom Power
- Current Draw 3.8 mA
- Weight 459 g
- Dimensions 100 mm L x 100 mm W x 50 mm H
- Maximum Input +3.5 dBV (no pad), +18 dBV (with pad)
- Input Connection 1/4″ Jack
- Output Connection XLR Output, 1/4″ Thru