Lundahl High level 600 ? tube amplifier mic/line input transformer, LL7906

Mic/Line Input Transformer LL7906

The LL7906 is a large, high level, high performance audio transformer, pin compatible with our LL17905, but with an internal structure better optimized for high turns-ratio step-up applications. The transformer combines very high secondary level capability (+37 dBU [54.5V rms] @ 50 Hz ) with low copper resistance. The LL7906 consists of two coils, each with two primary and one secondary windings separated by electrostatic shields. The core is a high permeability mu metal lamination core. The transformer is magnetically shielded by a mu metal case.

Turns ratio: 1 + 1 + 1 + 1 : 5.6 + 5.6
Dims (Length x Width x Height above PCB (mm)): 66 x 32 x 21

Spacing between pins: 5.08 mm (0.2")
Spacing between rows of pins: 5.08 / 45.72 mm (0.2 / 1.8")
Weight: 155 g
Rec. PCB hole diameter: 1.5 mm

Static resistance of each primary (average): 24 W
Static resistance of each secondary (average): 450 W
Distortion (primary connection L1, source impedance 150 W):
+ 8 dBU primary level, 50 Hz: 0.1 %
+ 16 dBU primary level, 50 Hz: 1 %

Self resonance point: 30 kHz

Optimum termination for best square-wave response
(Connections L1-R2 [1:11.2], source imp. 200W): 80kW

Frequency response:
(source and load as above, connection L1-R2, secondary side balanced
with or without grounded centertap): 10 Hz - 45 kHz +/- 1 dB

Frequency response
(source and load as above, connection L1-R2, secondary side
unbalanced with pin 23 grounded): 10 Hz - 25 kHz +/- 1 dB

Isolation between primary and secondary windings/ between windings and shield: 4 kV / 2 kV