Lundahl Line input/output transformer, LL1949

Line Input Transformer 2+2 : 1+1 LL1949

LL1949 is a high-level line input transformer normally used 2:1. The windings are arranged to give perfect symmetry if the transformer is used in phase splitting input applications. The two-coil structure also greatly improves immunity to external magnetic fields from e.g. power supplies and motors. Coils are wound using Cardas high purity post annealed audiophile grade copper wire Primary and secondary windings are separated by electrostatic shields. The core is a high permeability mu metal core. The transformer is housed in a mu-metal can.

Turns ratio: 2 + 2 : 1 + 1

Dimensions (L x W x H above PCB, in mm) 47 x 28 x 24
Spacing between pins 5.08 mm (0.2")
Spacing between rows of pins 35.56 mm (1.4")
Rec. PCB hole diameter: 1.5 mm
Weight: 115 g
Static resistance of each primary: 81W
Static resistance of each secondary: 20 W
Distortion (primaries connected in series, source impedance 600W ): + 24 dBU 0.1% @ 50 Hz + 29 dBU < 1 % @ 50 Hz
Self resonance point: > 150 kHz
Frequency response (source 600W, load 10 kW, serial connection, ref 1 kHz, 6dBU input signal): 10 Hz -- 120 kHz +/- 0.5 dB
Phase response (deviation from linear phase) 20 Hz 20kHz, +/- 0.5 Isolation between windings/ between windings and shield: 4 kV / 2 kV