
Amorphous Core Moving Coil Input Transformer
LL1931
LL1931 is a high performance moving coil step-up transformer. The transformer combines our unique uncut
amorphous cobalt core and our dual coil structure with Cardas high purity copper wire in an oversized design. The
objective is to provide the best possible MC transformer, cost-no-object. The dual-coil structure greatly improves
immunity to external magnetic fields from power supplies, motors etc.. The transformer is housed in a mu-metal can.
Turns ratio: 1 + 1 : 8 + 8
Pin layout (viewed from component
side) and winding schematics:
Dimensions (L x W x H above PCB, in mm)
43 x 28 x 22
Spacing between pins
5.08 mm (0.2")
Spacing between rows of pins
30.5 mm (1.2")
Rec. PCB hole diameter:
1.5 mm
Weight:
80 g
Static resistance of each primary:
1.8 Ω
Static resistance of each secondary:
105 Ω
Frequency response (serial connection, source 50 Ω,
no load / secondaries open):
10 Hz -- 100 kHz +/- 1.0 dB
Isolation between windings/ between windings and core: 3 kV / 1.5 kV
Connection alternatives:
R090627
Serial-serial connection 1 : 8
LUNDAHL
TRANSFORMERS
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
8
2
1
4
5
9
10
7
6
+
Parallel-serial connection 1:16
4
2
1
10
9
7
5
6
LL1931
Top view 8
Can + core
+
+
4
2
1
10
9
7
5
6
LL1931
Top view 8
+
4
2
1
10
9
7
5
6
LL1931
Top view 8
Cartridge is grounded through primary
center tap. If phono preamp input is
unbalanced, connect pins 9 and 8 to input
ground.
Cartridge is grounded through primary
“cold”. If phono preamp input is
unbalanced, connect pins 9 and 8 to input
ground.
If cartridge cable is unbalanced (such as
a coaxial cable), ground cartridge
through pin 2 and not through pins 1+4.