Hammond 1750JA 40W Deluxe Blues/Hot Rod Output Transformer, 4/8 Ohm

The 1750JA is a 40 watt push-pull output transformer for tube guitar amplifiers, designed as a drop-in replacement for the original unit in the Fender Deluxe Blues and Hot Rod amplifiers listed in the ordering table. The ordering table lists it as similar to Fender part numbers 47269 and 50438, which makes it a practical service part for these amplifiers.

It provides a 4,250 ohm centre-tapped primary and dual secondary taps at 4 ohm (green/yellow) and 8 ohm (green) with a black common. Typical DC resistance is 82.0 ohms brown-red and 108.3 ohms red-blue on the primary, 0.253 ohm black-green/yellow and 0.462 ohm black-green on the secondary. At 1.0 kHz, 1.0 V open circuit, the primary measures 11.40 H (72.0 KOhm); the secondaries 28.86 mH (259.20 ohm) and 55.60 mH (457.80 ohm). Primary leakage inductance is 31.39 mH.

Frequency response is 70 Hz to 15 kHz (0/-1 dB reference @ 1 kHz) with distortion under 1% at 70 Hz. The paper winding and materials were kept as close as possible to the original part to preserve the stock tone. Dielectric strength is 2000 VRMS, and the temperature range is -40 to 105 degC.

The open-style frame has 11 in minimum leads. Drawing dimensions are A 2.500 in, B 3.150 in, C 3.256 in, D 2.000 in, E 2.150 in and F 2.650 in, with G 0.188 x 0.375 in. The 1750JA is RoHS and REACH compliant and ships at 3 lbs (1.36 kg).