Hammond 1140-LU-G 600 Ohm +27 dBu 1:1 Line Output Transformer

The 1140-LU-G is a 1:1, 600:600 line output transformer and the highest-level 1:1 option in the 1140 Series, able to drive 600 Ω loads up to +27 dBu at 20 Hz. The 1140-LU-F drawing points to the 1140-LU-G as the better performer where a 1:1 ratio is needed. It suits studio, broadcast and live sound designers who want maximum headroom from a transformer-balanced output.

Bi-filar windings on an 80% Ni core give very low distortion and good output levels: rated THD at 20 Hz is 0.001%, and the frequency response is -0.02 dB at 20 Hz and +0.02 dB at 20 kHz. The drawing lists THD of 0.01% at 1 kHz and 0.001% at 20 Hz (4 dBu), 105 dB common mode rejection at 60 Hz and 75 dB at 3 kHz, and phase shift of 0.10° at 20 Hz and -1.0° at 20 kHz.

DCR is 40 Ω on each winding at 20 °C, typical primary input impedance is 680Ω and secondary output impedance 80Ω at 1 kHz and 0 dBu, capacitance to shield and case is 25 nF primary and 80 pF secondary, and 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-G is open style (not Mu Metal) for chassis mounting, with 8" minimum colour-coded leads (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).