Lundahl Amorphous Core Interstage transformer, LL2756AM

Lundahl Amorphous Core Tube amplifier interstage transformer LL2756

The LL2756AM is a three-section dual coil C-core tube amplifier interstage transformer. The coil is wound using our low capacitance, high internal isolation technique with internal multilayer isolation foil where layer-to-layer signal voltage is big. Winding order is chosen to minimize destructive capacitive energy build-up between primary and secondary sections. The core is an audio C-core of our own production.

Turns ratio 1+1 : 1+1

Weight: 1.35 kg
Static resistance of each primary: 180 W
Static resistance of secondary: 180 W
Isolation between windings / between windings and core: 4 kV / 2 kV
Max recommended DC current through primary windings: 120mA (5W heat dissipation)

Primary inductance (approx): 70 H
Max primary signal, at 30 Hz (Operating point 0.9 T): 180V r.m.s. (500V peak-peak)

Frequency response connected as below, source 4.5k, load 50 pF // 50k (with V+ connected to ground): -3dB at 12Hz; -3dB at 40kHz, +/- 1dB 25Hz 30kHz