Amplimo 12SE3K3H Output Transformer Single-Ended 12 Watt | 3,3 kΩ

Highlights of the Amplimo 12SE3K3H

• Wide bandwidth toroidal tube output transformer
• 12 W nominal power with 3250 Ω primary impedance
• 0, 4 Ω and 8 Ω secondary taps, with one tap used at a time
• 40% ultralinear tap with 86 mA nominal primary DC current
• -3 dB frequency bandwidth of 14 Hz to 85 kHz at 1 mW
• Potted in a black textured aluminium shell with M8x20 centre bolt mounting
• Supplied with mounting hardware

Product details Amplimo 12SE3K3H

Amplimo 12SE3K3H Wide bandwidth toroidal tube output transformer 12 W 3.25 kΩ

The 12SE3K3H is designed as a wide bandwidth toroidal output transformer for tube amplifier projects. With its 3250 Ω primary impedance and 0, 4 Ω and 8 Ω secondary options, it provides the output-stage interface needed for suitable speaker loads. Use only one secondary tap at a time.

Performance is specified for a -3 dB frequency bandwidth of 14 Hz to 85 kHz at 1 mW, with power bandwidth starting at 19 Hz. The transformer supports 12 W nominal power, 86 mA nominal primary DC current, and 172 mA primary saturation current, making it a precise choice among audio components for single-ended tube output stages.

The electrical design includes a 26 H primary inductance, 14 mH primary leakage inductance, 550 pF primary capacitance, and 90 Ω primary DC resistance. The 40% ultralinear tap gives additional circuit flexibility for tube amplifier designs that use UL operation.

The transformer is potted in a black textured aluminium shell and measures 126 mm in diameter by 65 mm high. It mounts with an M8x20 centre bolt, weighs 2.8 kg, and is supplied with mounting hardware and 200 mm leads. Wiring is colour coded: black for anode, white for UL, red for B+, green for 0 Ω, orange for 4 Ω, and brown for 8 Ω. All unused wires must be insulated with heatshrink.