Mini jack converters for microphones are available in many configurations and types. Technically adapters, they are used to connect microphone cables with XLR or 1/4-inch plugs to camcorders, computers, portable recorders and other devices with a 3.5mm (1/8 inch) microphone input. Mini jack converters allow connection flexibility and equipment compatibility, but the correct type must be employed for devices to function properly.
Microphone Adapter Anatomy and Configuration
Common mini jack converters for microphones include a female XLR or 1/4-inch jack (also called "TS" for tip-and-sleeve) to male mini plug. In their simplest form, these connectors passively route the wiring of the microphone cable's larger plug to 3.5mm mini plug format. The difference between a jack and a plug is in the converter's physical design; a plug is a male connector that fits into a female jack. For typical microphone-to-computer use, a microphone cord with a male XLR or 1/4-inch plug is inserted into the connector's female jack terminating into a 3.5mm plug. This plug is then inserted into the computer's 3.5mm jack.
Impedance Matching
While wire configuration and plug-matching may seem a straightforward concept, simple adapters will not work on all equipment due to differing output impedance levels of microphones and input devices. Professional microphones with XLR connectors are of the low-impedance variety, and are not directly compatible with most 3.5mm input devices -- which are almost always high-impedance. Connecting a low-impedance microphone to a high-impedance device results in low audio levels, which can be solved by using an adapter with a built-in impedance-matching transformer. Connecting 1/4-inch high-impedance microphones is generally not a problem.
Stereo and Mono Mini Jack Adapters
Another common issue involves stereo-to-mono connections. Many 3.5mm input jacks are wired in stereo and require a female mono XLR or 1/4-inch adapter, terminating to a stereo 3.5mm plug. This mono-to-stereo wiring is handled inside the adapter and allows a mono microphone to be heard on both the right and left sides of a stereo input machine. If a mono-to-mono adapter is used, the microphone signal will only appear on one side of the audio output. Stereo "Y" adapters terminating to a single 3.5mm stereo plug are available for dual microphone use and a true stereo input result.
Other Considerations
Adapters with attached cables perform the same function as standard adapters, but offer numerous advantages. Large plugs coupled with adapters can put strain on the input jack and risk breaking or loosening over time. Cables lessen the strain on the jack by virtue of having the weighty microphone connector suspended by the cable, which may then be secured or placed on a flat surface. Adapters with female connectors on both ends allow matching male cables to be used when longer wire lengths are desired.
Decide
By consulting your microphone and input device specification sheet or user manual, you can determine the correct jack and plug configuration and output and input impedance requirements. Defining the intended use for the microphone cable length and addressing jack safety concerns will help you determine whether a cable and adapter setup will meet your needs. When shopping, keep current and future use and expandability in mind.
Tags: jack converters, Adapters with, converters microphones, female jack, input devices
