Ko12

The Ko12 is a faithful reproduction of the legendary UTC O-12, originally designed as a line output transformer but famously used in reverse as the input transformer in early UREI/UA 1176 compressors.
Using an 80% nickel Permalloy core, carefully matched DCR and inductance, this replica delivers the same smooth character and subtle coloration that made the original so musical.
Ideal for 1176 builds, vintage restorations, or any design seeking authentic O-12 tone.
 
General Specifications
Turn Ratio: 1:1.58 (200:500 Ω bridging, reverse wired for 1176 input)
Nominal Impedance: 200 / 500 Ω
Primary DCR: 41.5 Ω
Secondary DCR: 16 Ω
Primary Inductance: 20 H @ 100 Hz
Core: Permalloy 80% Ni (high-permeability laminations)
Max Level: +8 dBm (before 2% THD @ 30 Hz)
Configuration: Floating windings, shielded