Lundahl LL1676 High Level Input Transformer for Tube Amplifiers

Highlights of the Lundahl LL1676

• High level tube amplifier input transformer with 1+1:2+2 turns ratio
• Two coils with two-section primary windings and high level secondary windings
• Amorphous strip core with less than 0.5° phase shift at 10 Hz
• Mu-metal housing for magnetic shielding
• 10 Hz to 40 kHz frequency response within ±0.5 dB with 600 Ω source and 10 kΩ load
• 3 kV primary to secondary isolation and 1.5 kV winding to shield isolation

Product details Lundahl LL1676

Lundahl LL1676 High Level Tube Amplifier Input Transformer 1+1:2+2

The LL1676 is designed for high level input use in tube amplifier circuits. As part of a carefully built signal path, it is a precision audio component with two coils, each combining a two-sectioned primary winding and a high level secondary winding separated by electrostatic shields.

Its two-component amorphous strip core provides very high permeability, helping the transformer achieve a phase shift of less than 0.5 degree at 10 Hz. This makes the LL1676 well suited to demanding amplifiers where low-frequency phase accuracy and high level handling are important.

Performance is specified at 10 Hz to 40 kHz within ±0.5 dB with a 600 Ω source and 10 kΩ load, with the -3 dB point at 80 kHz. The self-resonance point is 70 kHz, and the recommended termination for best frequency response with a 600 Ω source is 10 kΩ to 33 kΩ.

The LL1676 is magnetically shielded by a mu-metal housing and is built for PCB mounting. It measures 43 x 28 x 21 mm above the PCB, weighs 80 g, uses 5.08 mm pin spacing with 30.48 mm row spacing, and requires a recommended PCB hole diameter of 1.5 mm.