Lundahl Microphone Transformer, LL1940

Dimensions
(L x W x H above PCB, in mm)

31 x 25 x 16

Weight

35 g

Turns ratio

9 : 1 + 1

Spacing between pins

3.81 mm (0.15")

Spacing between rows of pins

22.86 mm (0.9")

Rec. PCB hole diameter:

1.5 mm

Static resistance of primary (pins 1-4):

1.5 k?

Static resistance of each secondary (pins 6-7, 9-10):

34?

Max primary signal level.

18V RMS at 20Hz
45V RMS at 50 Hz

Primary no load impedance

30 k? at 50 Hz

Frequency response. Source impedance 10k. Load 600 ohms Secondaries connected in parallel

20 Hz 50kHz + 0 / - 3 dB
40Hz 30 kHz + 0 / -1 dB

Frequency response. Source impedance 50k. Load 600 ohms Secondaries connected in parallel

50 Hz 40kHz + 0 / - 3 dB

Distortion. Source impedance 10k.

Approx 1% THD at 50Hz, 20dBU primary level.

Isolation between windings/ between windings and core:

4 kV / 2 kV