Telefunken TD-1 Passive Mono DI
The Telefunken TD-1 Passive Mono DI is a premium-quality direct box designed to deliver rich, natural tone and bulletproof reliability for both stage and studio applications. With its precision-engineered transformer and rugged design, the TD-1 is crafted for audio professionals who demand transparent signal conversion without sacrificing warmth, depth, or dynamic range.
At its core, the TD-1 features a hand-wound OEP/Carnhill transformer — the same class of components found in high-end vintage analog equipment. This transformer provides galvanic isolation, ensuring a clean and hum-free signal path from unbalanced instrument sources to balanced audio systems. The result is a beautifully open and musical character that enhances everything from electric guitars and basses to keyboards, synths, drum machines, and even vintage samplers.
The passive circuitry eliminates the need for phantom power or batteries, making the TD-1 an ideal “set it and forget it” solution in live rigs or studio racks. Its high headroom allows it to handle hot signals without distortion, while its low output impedance ensures compatibility with long cable runs and various mic preamps. Whether you’re tracking a DI bass line, re-amping guitar tracks, or performing live with multiple synths, the TD-1 guarantees optimal signal transfer and sonic integrity.
Designed for real-world use, the TD-1 is housed in a durable steel enclosure with a sleek black powder coat finish, built to withstand the rigors of touring and frequent setup/teardown. Premium Neutrik connectors provide secure, noise-free connections, and the ground lift switch allows you to eliminate hum caused by ground loops with a single flip.
From the moment you plug it in, the TD-1 stands out as more than just a utility box — it’s a sonic enhancer that adds polish and character to your instrument tone. It’s especially favored by audio engineers looking to capture the true essence of electric and electronic instruments with added analog warmth and clarity.
Ideal Applications:
- Connecting electric guitars and basses directly to mixing consoles or interfaces
- Recording synthesizers, keyboards, and drum machines with pristine signal clarity
- Live sound setups where clean, reliable DI signal paths are crucial
- Re-amping and integrating line-level gear in hybrid analog/digital studios
- Broadcast and post-production environments where signal noise must be minimized
Key Features:
- High-performance OEP/Carnhill transformer made in the UK
- Warm, vintage-inspired tone with wide frequency response
- Passive operation — no external power required
- Ultra-low distortion and high signal headroom
- Ground lift switch to prevent ground loop hum
- High-quality Neutrik connectors for long-term reliability
- 1/4” input and thru jacks, XLR balanced output
- Rugged steel enclosure with black powder-coated finish
- Hand-assembled in the USA using premium components
Technical Specifications:
- Type: Passive Mono Direct Injection (DI) Box
- Transformer: Custom OEP/Carnhill, UK-made
- Frequency Response: 20 Hz – 20 kHz, ±1 dB
- Input Impedance: 140 kΩ (typical)
- Output Impedance: 150 Ω (typical)
- Maximum Input Level: +18 dBu @ 50 Hz, 0.1% THD
- Input: 1x 1/4” TS jack
- Thru: 1x 1/4” TS jack (parallel)
- Output: 1x balanced XLR male
- Ground Lift: Yes
- Enclosure: Powder-coated steel
- Dimensions: 4.88” x 3.1” x 1.9” (124mm x 79mm x 48mm)
- Weight: 1.1 lbs (0.5 kg)
- Manufactured in: USA
If you’re looking for a DI box that does more than just convert signal — one that adds depth, dimension, and unmistakable analog character — the Telefunken TD-1 Passive Mono DI is your go-to solution. It’s a favorite among touring professionals and studio engineers who refuse to compromise on tone, reliability, or build quality.