Hammond 1140-MS-A 150 Ohm 1:1 Microphone Isolation 2-Way Splitter

The 1140-MS-A is a 1:1 microphone isolation transformer from the 1140 Series. It provides isolation for a standard 150 Ω microphone source feeding a 1000 Ω microphone preamp, and can be used as a straight isolation transformer or in a typical 2 way splitter application. Live sound engineers, broadcast facilities and snake or splitter builders are the natural buyers.

The impedance ratio is 150:150 with a 1:1 turns ratio. Rated performance is +2.0 dBu maximum input at 20 Hz, 0.05% THD at 20 Hz and a frequency response of -0.14 dB at 20 Hz and -0.06 dB at 20 kHz. The drawing gives typical THD of 0.002% at 1 kHz and 0.18% at 20 Hz (-20 dBu), 90 dB common mode rejection at 60 Hz and 75 dB at 3 kHz, and 1.03K primary input impedance and 235 secondary output impedance at 1 kHz and -20 dBu.

It has wide bandwidth and excellent shielding from the mu metal can, with dual shields around a nickel alloy core. DCR is 44.0 on both windings at 20 °C, capacitance to shield and case is 170 pF primary and 150 pF secondary, and dielectric strength is 500 Vrms.

The 1140-MS-A is chassis mounted with colour-coded leads: brown/orange primary, green and green/yellow secondary, grey and grey/white shields and violet can ground. It is RoHS and REACH compliant, made in Canada, and ships at 0.2 lbs (0.09 kg).