From MetroAmp Wiki
Drake part # 1202-84 output transformer. Found in Marshall 100 watt amps circa 1965 - 1966. The fabled 45/100 amps.
4kΩ primary impedance for use with (4) KT66 tubes
8 and 16Ω and 100 volt line output taps
Color code for Metroamp replica of Drake 1202-84. I chose to include the 4Ω tap and there is also a 100V line winding tucked inside the covers. This is important as it affects the tone.
NOTE: prior to April 2008 the color code is
Primary- brown, red CT, blue.
Secondary- black common, yellow 4 ohm, green 8 ohm, orange 16 ohm.