Hammond 1140-MS-C 4-Way 150 Ohm Mic Splitter Transformer, Chassis Mount

The 1140-MS-C is a studio grade microphone splitter transformer from the 1140 Series, built for chassis mounting. It has one 150 Ω primary and three 150 Ω secondaries (impedance ratio 150:150:150:150, turns ratio 1:1:1:1), so a single 150 Ω microphone source can feed up to three isolated outputs.

According to the manufacturer's drawing, the transformer provides isolation for a standard 150 Ω microphone source into a 1000 Ω microphone preamp, and it can be used either as a straight 3-way isolation transformer or in a typical 4-way splitter application. The windings sit in a mu metal can and each winding has its own shield lead, which the drawing describes as dual shields for excellent shielding. The series is designed with nickel alloy cores for wide bandwidth.

Performance figures: maximum input of +11 dBu at 20 Hz, THD of 0.030% at 20 Hz in the series ordering table, and frequency response of -0.05 dB / +0.20 dB at 20 Hz / 20 kHz. The drawing's typical test data adds THD of 0.002% at 1 kHz (-20 dBu), common mode rejection of 120 dB at 60 Hz and 90 dB at 3 kHz, and 500 Vrms dielectric strength.

Connections are colour-coded flying leads: primary BRN–ORG, secondaries GRN–GRN/YEL, RED–RED/YEL and BLU–BLU/YEL, shields GRY, GRY/YEL, GRY/WHT and GRY/RED, and a VIO can-ground lead. The 1140-MS-C ships at 0.2 lbs (0.09 kg), is marked Made in Canada, and is RoHS and REACH compliant.