
Audio Split Transformer
LL1560
LL1560 is an audio transformer specially built for active splitting.
Each of the four secondary windings is surrounded by primary winding parts. This results in a low leakage
inductance and ensures that output signal is maintained on three of the secondary windings even if one is short-
circuited, provided of course that driving power is available.
The primary windings should be used in parallel.
Turns ratio: 2 + 2 : 1 + 1 + 1 + 1
Dims: (Length x Width x Height above PCB (mm)) 47 x 34 x 23
Pin Layout (viewed from component side) and Windings Schematics (simplified):
Housing: Mu-metal
Core: Audio C-core
Spacing between pins: 2.54 mm (0.1")
Spacing between rows of pins: 35.56 mm (1.4")
Weight: 130 g
Rec. PCB hole diameter: 1.5 mm
Static resistance of each
primary (average): 120 Ω
Static resistance of each
secondary (average): 55 Ω
Secondary leakage inductance (secondaries in series, primary short circuited): < 1 mH
Max. secondary level (each secondary) + 26 dBU @ 50 Hz
No-load primary impedance(primaries in parallel, primary level):> 1 kΩ @ 50 Hz, +20 dBU
Balance of output (according to IRT, source 10 Ω , Load 600 Ω): > 60 dB
Frequency response
(source 10 Ω, each sec. loaded with 600 Ω, 0
dBU sec. level): 20 Hz - 50 kHz +/- 0.5 dB
Isolation between windings / between windings and shields: 4 kV / 2 kV
Driving circuitry, mixed feedback, 2:1+1+1+1, suggested by A. Offenberg, NRK
11
22
9
1
3
21
20
15
14
13
12
17
19
Core and can 17
1
3
9
11
R
R
R1
R1 is approximately 60 ohms.
Select R1 for good THD at LF and for
good square wave response
+ in
R980616
11
22
9
1
3
21
20
15
14
13
12
17
19
Out 1
Out 2
Out 3
Out 4
21
22
19
20
15
14
13
12
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
LL1560
(top view)