The flexibility of Triad J Series tranformers permits amplifiers to exceed broadcast standars. Single Hole mounting allows rotation for maximum hum reduction. Alloy shielding for up to 60 dB hum reductin (60 to 80dB in Types A-11j, A-12J, A-13J. Wide Frequence Response. Input units are electrostatically shielded. Legible circuit diagrams permanently affixed to case. Part # A-15J: Bal-Line/Mike - PRI: 600/250/50 to SEC: 20,000 - 1.5:5.77 - Frequency Response (+-3dB): 30-15,000Hz - 1.75x1.375in - Leads