
Microphone Transformer / D-I Box Transformer
LL1530
LL1530 is a microphone input transformer used for matching a 200 or 800 Ω microphone to 10 kΩ or for
matching a high impedance source to a microphone input.
The transformer consists of two coils, each with one primary and one secondary winding separated by an
electrostatic shield, and a high permeability mu-metal core. The transformer is encapsulated in a mu-metal case
for magnetic shielding.
For best performance, the high impedance side of the transformer (3.5 + 3.5) should be connected in series.
Turns ratio: 1 + 1 : 3.5 + 3.5
Dims (Length x Width x Height above PCB (mm)): 38 x 23 x 16
Pin layout (viewed from component side) and winding schematics:
Spacing between pins: 5.08 mm (0.2")
Spacing between rows of pins: 27.94 mm (1.1")
Offset of earth pin from adjacent row: 2.54 mm (0.1")
Weight: 46 g
Rec. PCB hole diameter: 1.5 mm
Static resistance of each primary: 42Ω
Static resistance of each secondary: 790Ω
Distortion (primaries connected in series, source impedance 800Ω ): + 6 dBU (primary level) 0.1% @ 50 Hz
+16 dBU (primary level) < 1% @ 50 Hz
Self resonance point : > 100 kHz
Recommended termination for best square-wave response:
connection 1:3.5 10 kΩ in series with 220 pF
connection 3.5:1 2 kΩ in series with 2.2 nF
connection 7:1 1 kΩ
Frequency response
(1:3.5, source 800Ω , load 10kΩ in series with 220 pF): 20 Hz -- 30 kHz +/- 0.3 dB
Isolation between windings/ between windings and shield: 4 kV / 2 kV
Connection alternatives (Component side view):
R980622
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Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
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LL1530
(top view)