Hammond 1750FA 15W Marshall DSL15H Output Transformer, 8/16 Ohm

The 1750FA is a 15 watt push-pull output transformer for tube guitar amplifiers, designed as a drop-in replacement for original units such as the one in the Marshall DSL15H (similar to OEM part DSL-15 OPT). Amp model names are listed by the manufacturer for reference only, and the manufacturer states it is not affiliated with the amplifier companies.

The transformer has a 7,000 ohm centre-tapped primary and two secondary taps, 8 ohm and 16 ohm, sharing a black common. Typical DC resistance is 170.0 ohms brown-red and 150.0 ohms red-blue on the primary and 1.00 ohm black-yellow on the secondary. At 1.0 kHz, 1.0 V open circuit, the brown-blue primary measures 87.2 H (401K ohm); the black-green secondary 17.07 mH (591.7 ohm) and the black-yellow secondary 45.52 mH (1.175K ohm). Primary leakage inductance is 28.96 mH.

Frequency response is 70 Hz to 15 kHz (0/-1 dB reference @ 1 kHz), and distortion is less than 1% at 70 Hz. The unit is bobbin wound, with materials and design specifications kept as close as possible to the original to preserve the stock tone.

Its open-style construction provides 9 in minimum leads: brown, red (centre tap) and blue on the primary; black common, green 8 ohm and yellow 16 ohm on the secondary. Drawing dimensions are A 3.687 in, B 2.380 in max, C 2.500 in and D 3.125 in. Ratings are 1500 VRMS dielectric strength and -40 to 105 degC. It is RoHS and REACH compliant and ships at 2 lbs (0.91 kg).