• Aimil Limited

Microphone Preamplifier

Meggitt Sensing Systems, a Meggitt group division, has introduced the Endevco® model EM26CF, a general purpose ½” Isotron® (IEPE) microphone preamplifier, designed for direct compatibility with prepolarized condenser microphones in support of a variety of precision acoustic test requirements. The model EM26CF is designed for use with all Endevco prepolarized microphones and incorporates use of an Isotron power supply to offer a low inherent noise level, large dynamic range and a wide frequency response from 2.5 Hz to 100 kHz. Its small and robust ceramic thick-film substrate construction offers high-input impedance and is shielded by a guard ring to minimize the influence of stray capacitance and microphonic interference. Preamplifier components are encased in all-stainless steel housing with an integral BNC output connector for maximum strength and durability. In addition, it offers two user-selectable flush-mounted switch settings for optimal gain and filtering. Gain selections include 0 dB for normal conditions and +20 dB for enhancing weak microphone signals. Filter settings allow the user to select an A-weighting filter, as typically required for standard measurements; a linear setting, to allow the microphone signal to pass unfiltered; or a high-pass filter, to eliminate unwanted low frequencies. These settings offer additional flexibility, facilitating their use across a variety of applications, including vehicle pass-by noise testing, environmental noise analysis and building acoustics.