Lundahl Line output transformer, LL1930

Audio transformer for tube preamp line output LL1930

LL1930 is designed to be a line output transformer for tube preamp parafeed output applications. The core is a high permeability mu metal core. The transformer has no internal Faraday shield or magnetic shield housing.

Turns ratio: 5.8 + 5.8 : 1 + 1

Dimensions (L x W x H above PCB, in mm): 47 x 28 x 23
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: 105g
Static resistance of each primary (pins 1-2, 4-5): 610?
Static resistance of each secondary (pins 6-7, 9-10): 16?

Distortion at 30 dBU primary signal. Source impedance 4.5k.
Primaries connected in series. < 0.1% at 50Hz < 1% at 25Hz

Frequency response. Connection and signal level as above.
Secondary load 10k. 20 Hz 30kHz < +/- 0.1 dB

Isolation between windings/ between windings and core: 4 kV / 2 kV