Direct Box Transformer

Direct box or direct injection (di)transformers are used for converting analog audio signals from one “format” to another. They change high impedance and/or unbalanced signals to low impedance, balanced signals ready for a mic channel. The purpose for this is twofold. High impedance signals can easily lose their tone if they have to travel any distance at all. Unbalanced signals are more susceptible to noise over any distance compared to a balanced signal. The proper DI transformer can fix both of those problems at the same time.

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Without getting too far into the technical weeds, there is a trade off that occurs between the input and output of any transformer. The yin and the yang is that the higher the output level of the transformer, the more “stress” that’s put on the input signal. A lower output level is “easier” on the original signal, but there is less signal for the next piece of gear in line to work with. In pursuit of the Goldilocks threshold,Crimson offers standard DI transformers in two flavors – the CT-121di and CT-841di.

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The CT-121di has a 12:1 turns ratio and was designed with a passive source in mind such as acoustic guitar. It features a hum bucking internal configuration and is housed in a noise fighting mu-metal can. This can also provides a simple, secure mounting scheme. The CT-841 is slanted toward active outputs. It’s 2 output windings maybe connected in series or parallel. The series configuration yields an 8:1 ratio appropriate for line level sources. Connected in parallel, the ratio is 4:1 for instrument level applications. The CT-841di is also supplied in our mu-can for noise resistance and ease of installation.

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For OEM applications, we can offer a wide variety of options including different turns ratios and pcb mounts with or without a mu can.