Lundahl LL1592 Audio transformer

The windings are arranged to give a high degree of symmetry if the transformer is used for phase splitting. The dual-coil structure also greatly improves immunity to external magnetic fields from e.g. power supplies and motors. Primary and secondary windings are separated by electrostatic shields.. The transformer is housed in a mu-metal can.

Dimensions (L x W x H above PCB, in mm): 47 x 28 x 20
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: 83 g
Static resistance of each primary: 270 Ohm
Static resistance of each secondary: 270 Ohm
Distortion (primaries connected in series, source impedance 600 Ohm): + 23 dBU 0.1% @ 40 Hz, + 29 dBU < 1 % @ 40 Hz
Self resonance point: > 120 kHz
Suggested termination for best square wave response, serial-serial connection.
7k + 400pF
Frequency response (serial connection , source 600 Ohm, load 20 kOhm, no terminating network 10 Hz -- 50 kHz +/- 1.0 dB
Frequency response (serial connection , source 600 Ohm, load 100 kOhm in parallel with 7k + 400pF): 10 Hz -- 100 kHz +/- 1.0 dB
Phase splitting balance (connection 2:1+1. Source 1kOhm, load (20kOhm? + 20kOhm) in parallel with 7k + 400pF):
>46 dB, 10Hz ? 50kHz
Phase response (deviation from linear phase) (source 600 ohm, load 10k (Audio Precision))
10 Hz ? 20kHz, < 2°
Isolation between windings/ between windings and shield: 3 kV / 1.5 kV.

Suitable transformer for 1:1 applications with 600 ohm source and at least 10K reflecting impedance output 600/10K.