Lundahl LL1660-S-10 Interstage Transformer for Tube Amplifiers 10mA

The LL1660-S-10 is a Lundahl interstage transformer for tube amplifier phase splitting applications, featuring Faraday shields, low-capacitance winding and a high-flux audio C-core.

Highlights of the Lundahl LL1660-S-10

• Interstage transformer for tube amplifier phase splitting applications
• Internal shielding helps to improve balance in phase splitting use
• Special low-capacitance winding technique for strong high-frequency performance
• High-flux, low-distortion audio C-core construction
• Supports push-pull to push-pull and single-ended to push-pull connection alternatives
• 4 kV primary-to-secondary isolation and 2 kV winding-to-core isolation

Product details Lundahl LL1660-S-10

Lundahl LL1660-S-10 Tube Amplifier Phase Splitting Interstage Transformer 10mA

The Lundahl LL1660-S-10 is designed for interstage use in tube amplifiers, particularly where phase splitting is required. Internal Faraday shields improve balance in these applications, while the small core air gap allows for a degree of DC current unbalance.

As an audio component, the LL1660-S-10 focuses on signal integrity through a special low-capacitance winding technique and a high-flux, low-distortion audio C-core. This construction supports wide bandwidth operation, with connection alternatives specified for push-pull to push-pull and single-ended to push-pull interstage configurations.

In the push-pull to push-pull connection alternative, the transformer uses a 2.25 + 2.25 : 2 + 2 ratio, with a primary inductance of 290 H, a frequency response of 20 Hz to 25 kHz at ±1 dB with 15 kΩ source impedance and secondaries open, and a maximum output voltage of 2 x 260 V RMS at 30 Hz. In the single-ended to push-pull alternative, it uses a 2.25 : 2 + 2 ratio, with 42 H primary inductance, 25 Hz to 30 kHz response at ±1 dB with 3.5 kΩ source impedance and secondaries open, and 220 V RMS maximum output at 30 Hz.

The transformer weighs 0.75 kg and uses a winding structure with a 1 + 1 + 1 + 1 : 2.25 + 2.25 turns ratio. Static resistance is 315 Ω for winding A, 240 Ω for winding B and 625 Ω for winding C. It is rated for a maximum current of 50 mA through any single section, with 4 x M3 mounting holes, 5.08 mm pin spacing, 45.7 mm row spacing and 1.2 to 1.4 mm pin diameter.