Hammond 1140-MS-B 150 Ohm 1:1:1 Microphone 3-Way Splitter Transformer

The 1140-MS-B is a 1:1:1 microphone isolation transformer from the 1140 Series with one 150 primary and two 150 secondaries. It provides isolation for a standard 150 Ω microphone source into a 1000 Ω microphone preamp and can be used as a straight isolation transformer or in a typical 3 way splitter application.

The impedance ratio is 150:150:150. Rated performance is +2.0 dBu maximum at 20 Hz, 0.030% THD at 20 Hz and a frequency response of -0.08 dB at 20 Hz and +0.06 dB at 20 kHz. The drawing lists common mode rejection of 120 dB at 60 Hz and 90 dB at 3 kHz, THD of 0.002% at 1 kHz and 0.10% at 20 Hz (-20 dBu), 560K primary input impedance and 220 secondary output impedance at 1 kHz and -20 dBu, and a 1:1:1 turns ratio.

It has wide bandwidth and excellent shielding from the mu metal can, with dual shields around a nickel alloy core. DCR is 48.0 on the primary and 48.0/48.0 on the secondaries at 20 °C, capacitance to shield and case is 500 pF for primary and secondary, and dielectric strength is 500 Vrms.

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