Lundahl LL1544A General Purpose Audio Transformer

Highlights of the Lundahl LL1544A

• Line input and general-purpose audio transformer for balanced and unbalanced circuits
• Two three-section coils with interleaved Faraday shields
• Two-component amorphous strip core for excellent low-signal sensitivity and high-level capability
• Flexible connection alternatives including 1:1, 1:2, 2:1 and 4:1 operation
• 10 Hz to 70 kHz frequency response within ±0.5 dB under recommended termination
• Compact PCB-mount format measuring 30 x 22.5 x 14.5 mm and weighing 27 g

Product details Lundahl LL1544A

Lundahl LL1544A General Purpose Audio Transformer

The Lundahl LL1544A is designed for use as a line input and general-purpose transformer in demanding audio components. It suits a wide range of applications, from bridging input configurations to microphone input circuits, and supports both balanced and unbalanced source and load connections.

Its construction uses two three-section coils with interleaved Faraday shields and a two-component amorphous strip core. This core combines high sensitivity at very low signal levels with strong high-level capability, while also helping to maintain excellent low-frequency phase response. For builders working with precision electromechanics, the LL1544A offers a compact and versatile transformer platform.

The LL1544A provides multiple connection alternatives, including 1:1, 1:2, 2:1 and 4:1 ratios depending on the selected winding configuration. Typical static resistance is 130 Ω per primary and 260 Ω per secondary, with a self-resonance point above 220 kHz. With a 600 Ω source and the recommended 6.7 kΩ + 470 pF termination in parallel with 56 kΩ, frequency response is 10 Hz to 70 kHz within ±0.5 dB at 0 dBU, with only 0.2 dB loss at 1 kHz.

The transformer is made for PCB mounting, with 2.54 mm pin spacing, 22.86 mm row spacing and a recommended PCB hole diameter of 1.5 mm. Isolation is rated at 3 kV between windings and 1.5 kV between windings and shields, making it suitable for compact professional and DIY audio circuit designs where flexible input transformer wiring is required.