Hammond 1750ORF 35W Orange Rocker 30 Output Transformer, 8/16 Ohm

The 1750ORF is a 35 watt push-pull output transformer for tube guitar amplifiers, designed as a drop-in replacement for original units such as the one in the Orange Rocker 30, and similar to OEM part OT119SL (reference only). The manufacturer notes that it is not affiliated with Orange and that amp model names are listed for reference purposes.

The part page lists a 6,000 ohm centre-tapped primary, while the drawing's electrical table and label show 6600 ohms CT; both are recorded in the specifications so you can compare against the original. The secondary offers 8 ohm (brown) and 16 ohm (red) taps with a black common. Typical DC resistance is 68.39 ohms black-white and 72.23 ohms white-yellow on the primary, and 0.602 ohm red-black on the secondary.

At 1.0 kHz, 1.0 V open circuit, the black-white primary measures 10.3 H (65.5K ohm), the white-yellow reading is 24.26 mH (390.7 ohm), and the red-black secondary 54.02 mH (798.6 ohm). Leakage inductance (yellow-white) is 18.25 mH. Frequency response is 70 Hz to 12 kHz (0/-1 dB reference @ 1 kHz) with distortion under 1% at 70 Hz.

The bobbin-wound, open-style unit has 12.0 in minimum leads stripped 0.5 in, with yellow and black primary leads and a white centre tap. Drawing dimensions are A 2.500 in, B 2.685 in, C 3.060 in, D 2.000 in and E 1.688 in, with G 0.203 x 0.375 in. It is rated 2500 VRMS and -40 to 105 degC, is RoHS and REACH compliant, and ships at 7 lbs (3.18 kg).