United Technologies Vintage Direct

Vintage-Style Large-Transformer Direct Box

The purest tone possible. The United Technologies Vintage Direct bridges the gap between classic tape-era workflows and today’s modern recording world. When engineers demand the very best, Vintage Direct delivers a huge, open sound powered by an equally massive transformer. The circuit is designed to remove the tone-robbing parts often found in lesser DI boxes. When you need the best, Vintage Direct delivers.

Featuring custom large-core United transformers

We did the research. While most DI circuits are simple, the best ones depend on great transformers — and that’s where Vintage Direct stands apart. Its design draws inspiration from early hand-wired DI boxes like the Wolfbox and Bruce Swedien’s Bass Box, both of which used large transformers from Triad, UTC, and others. Our research began with the UTC A12 transformer, first made in the early 1960s. We measured original units to accurately reproduce their winding ratios, bobbin and magnet wire materials, and lamination style. After years of testing different winding ratios and alloys, we settled on a high-nickel lamination design with a winding ratio very close to the classics that inspired it. United’s U.S.-made 5078 — one of the largest transformers you’ll find in a DI box. It delivers pristine low-noise performance, wide frequency response, exceptional headroom, and excellent noise rejection.

Flexible options with audiophile-grade components

We designed Vintage Direct so nothing stands between the source and the transformer that could compromise tone or add noise. Most passive DI boxes rely on smaller, unshielded transformers before the signal ever reaches the transformer. Vintage Direct avoids all of that. Instead, level adjustment is handled through the transformer’s output taps — a far more transparent way to control signal level without affecting tone. Vintage Direct uses three secondary winding configurations together with a precision resistor T-pad output attenuator to provide six evenly spaced output settings. True ground isolation helps reduce ground-loop hum during tracking. We also built in a large, well-shielded transformer that can handle both line-level and instrument-level signals without overload. It wasn’t the cheapest approach, but it guarantees top-tier performance and maximum tonal integrity. The custom audio-grade resistors are made in the USA for United by PRP, a component supplier to NASA.

More than a DI box — it’s a United

The Vintage Direct is one of the most exceptional passive DI boxes built in decades. Its aluminum chassis is rugged enough for the road and refined enough for the studio. A recessed front panel helps protect the controls from studio mishaps and stage wear, while removable feet offer flexible mounting options. With more than 50 years of combined industry experience, we poured years of research and development into this design. We can’t wait to hear what you create with it.

Don’t forget to take a look at our other United Studio Technologies products!

Visit the United Technologies website for more info.