The Endevco ½-inch preamplifier model EM26CF is a general purpose preamplifier optimized for use with prepolarized condenser microphones. It is a small, robust unit and uses an Endevco Isotron® power supply, eg. model 4416B. It has low inherent noise level, a large dynamic range and a frequency response from 2.5 Hz to 100 kHz. Gain and filter switch settings There are two flush-mounted switches for selecting various combinations of gain and filtering, i.e.: Gain switch settings: 0 dB - for normal microphone signals. +20 dB - for boosting weak microphone signals. Filter switch settings: A-weighting - as required in standard measurements. Linear - to let the microphone signal pass unfiltered. High-pass - to cut off unwanted low frequencies. The frequency responses of the A-weighting filter is shown in Fig.1. Its small ceramic thick-film substrate has a very high input impedance, and is shielded by a guard ring to minimize the influence of stray capacitance and microphonic interference. The model EM26CF can be used with all Endevco prepolarized microphones, namely: • ½-inch microphones: Models EM40AE, EM40AD and EM40AQ • ¼-inch microphones: Models EM40BE and EM40BD, using the optional ½-inch to ¼-inch adaptor It has an integrated BNC output connector. The casing is made of stainless steel for maximum strength and durability. • 0 dB and +20 dB gain settings • Linear, A-weighting and high-pass filter (20 Hz) settings • Isotron® inputs • Prepolarized microphones • ½-inch precision microphones • High levels and high frequencies Endevco® model EM26CF ½-inch microphone preamplifier with gain and filters Feartures / applications Description cmyk

Specifications Frequency response (cable load 4.7 nF): 2.5 Hz–100 kHz ±0.2 dB (typical for 0 dB gain and linear setting) Input impedance: 20 G Ù, 0.4 pF Output impedance (Cs = 20 pF, f = 1000Hz): < 50 Ù Noise (measured with 20 pF ½-inch dummy mic.): Linear, 0 dB: typically 8 ìV rms Linear, 20 dB: typically 65 ìV rms A-weighted, 0 dB: typically 10 ìV rms High pass, 0 dB: typically 10 ìV rms A-weighting filter: Compliant with IEC 61672-1 Class 1 High-pass filter: 3-pole butterworth, –3 dB at 20 Hz Gain: Typically: -0.25 dB Power-supply: 4 mA to 20 mA (typically 4 mA) Maximum signal-output voltage...