Hammond 1140-LU-DPC +24 dBu 49% Nickel PCB Line Output Transformer

The 1140-LU-DPC is a 600:600, 1:1 printed circuit mount line output transformer from the 1140-PC Series. It suits audio boards that need a transformer-coupled line output able to reach higher levels into a 600 Ω load.

According to its drawing, the transformer uses bi-filar windings and a 49% nickel core, giving low distortion levels and good output levels, and it can drive 600 Ω loads up to +24 dBu at 20 Hz. The drive signal should have no DC component and the source impedance should be as low as possible.

Measured typical values include THD of 0.001% at 1 kHz and 0.08% at 20 Hz (4 dBu), frequency response of -0.18 dB at 20 Hz and +0.03 dB at 20 kHz, and common mode rejection of 105 dB at 60 Hz and 75 dB at 3 kHz. Phase shift is 0.23° at 20 Hz and -0.7° at 20 kHz.

Each winding measures 40 Ω DC resistance at 20°C; primary input impedance is 680 Ω and secondary output impedance 80 Ω at 1 kHz. Capacitance is 20 nF (primary to shield and case) and 50 pF (secondary to shield and case), and dielectric strength is 250 Vrms. Note that the series ordering table prints the maximum input for the 1140-LU-DPC as -24 dBu, while the part drawing gives +24 dBu. The primary is PIN 2–PIN 4 and the secondary PIN 11–PIN 8. Shipping weight is 0.2 lbs (0.09 kg); RoHS and REACH compliant.