Direct Box Transformers

Carnhill’s range of direct box transformers


Direct Box transformers convert unbalanced line level signals to balanced microphone level signals to feed long cables while retaining bandwidth and eliminating hum. Extensively used with musical instrument hookups, they eliminate hum and buzz because of their excellent Common Mode Rejection Ratio. These noise problems can plague systems where guitars and stage instruments (keyboards, samplers, computer, and drum machines) are far from the mixer and abnormally high ground-voltage-differences are the norm.

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Our direct box transformers are available in:

  • Wire Lead – Standard wire termination with retainer clamp
  • PCB Mount – For direct soldering to printed circuit boards

See the table below to view the datasheets and associated ISO information for this product:

Product nameImpedance ratioTurns ratioMax input @ 20 Hz
A187A10C140k to 1k 11.55 to 1 + 22dBu