Hammond 1140-LU-E 600 Ohm +22 dBu Low-Distortion Line Output Transformer

The 1140-LU-E is a 1:1, 600:600 line output transformer from the 1140 Series. Bi-filar windings on an 80% Ni core give very low distortion levels and good output levels, and it can drive 600 Ω loads up to +22 dBu at 20 Hz. It is aimed at studio, broadcast and pro audio designers building transformer-balanced line outputs.

Rated THD at 20 Hz is 0.001%, and the frequency response is -0.03 dB at 20 Hz and +0.02 dB at 20 kHz. The drawing lists typical THD of 0.007% at 1 kHz and 0.001% at 20 Hz (4 dBu), 105 dB common mode rejection at 60 Hz and 85 dB at 3 kHz, and phase shift of 0.08° at 20 Hz and -0.80° at 20 kHz.

DCR is 40 Ω on both windings at 20 °C, with typical 680Ω primary input impedance and 80Ω secondary output impedance at 1 kHz and 0 dBu. Capacitance to shield and case is 20 nF primary and 70 pF secondary; dielectric strength is 250 Vrms. The drive signal should have no DC component and the source impedance should be as low as possible.

The 1140-LU-E is open style (not Mu Metal) for chassis mounting, with colour-coded leads of 8" minimum length (brown/orange primary, green to green/yellow secondary). It is RoHS and REACH compliant, made in Canada, and ships at 0.2 lbs (0.09 kg).