Lundahl LL1583 Audio transformer

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.

Turns ratio: 1 : 1 + 1

Technical Details:

• 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 ohms

• Static resistance of each secondary  (Pins 10 to 7 and pins 6 to 9): 95 and 130 ohms

• 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 150?  , load 10 k ohms

• 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