Lundahl LL1583 audio, Small Size Splitting Transformer

Splitting 1 direct + 2 isolated outputs. Small size mic. level transformer
with the same excellent noise immunity as the LL1581XL.

LL1583 - Small Size Splitting Transformer

In many splitting applications, the splitting transformer must have a high immunity to input common mode signals, to
stray magnetic fields from e.g. power transformers and to large ground potential differences in receiving systems.
In the design of the LL1583, we have used our well established two coil structure to create a transformer with a high
degree of symmetry. The transformer is built up from two primary windings (which should be used in parallel) and two
secondary windings. Each secondary winding is built up from two sections, one from each coil. Its own electrostatic
shields surround each secondary section. The symmetric structure results in an internal cancellation of noise signals
caused by external magnetic field. It also increases immunity to ground noise between secondary systems and reduces
the effects of input common mode signals.
The transformer is housed in a mu-metal can and is impregnated in solventless epoxy resin


Spacing between pins: 2.54 mm (0.1")
Spacing between rows of pins: 20.32 mm (0.8")
Recommended PCB hole diameter: 1.3 mm

Turns ratio: 1 : 1 + 1

Dimensions (Max. L x W x H above PCB(mm)) 28 x 17 x 15
Weight: 25 g
Static resistance of primary (in parallel) 56 Ω
Static resistance of each secondary (Pins 10 to 7 and pins 6 to 9): 95 and 130 Ω
Self resonance point : > 200 kHz
Distortion 0.1% @ -2 dBU, 50 Hz
1 % < @ 8 dBU, 50 Hz
Frequency response (Ref : -6 dBu, 1kHz) 10 Hz -- 120 kHz +/- 0.5 dB
Test arrangement: Parallel input - parallel output . Source 150Ω , load 10 kΩ
CMRR at 20 kHz (Source 600 ohms, load 2 x 10k) > 60 dB
CMRR at 20 kHz from sec. to sec. (Source 600 ohms, load 2 x 10k) > 40 dB
Isolation test primary - secondary / secondary - secondary / E1 - E2 4 kV / 2 kV / 1 kV RMS