Hammond 1750H 20W Deluxe Reverb Output Transformer, 8 Ohm

The 1750H is a 20 watt push-pull output transformer for tube guitar amplifiers, designed as a drop-in replacement for the original unit in Fender Deluxe, Deluxe 68 Custom Reverb and Deluxe Reverb 65 Reissue amplifiers. It is listed as similar to Fender part numbers 125A1A, 022640 and 041318, which makes it a common service part for technicians working on Deluxe-family amps.

It matches a 6,600 ohm centre-tapped primary to an 8 ohm secondary. Typical DC resistance is 428.0 ohms across the brown-blue primary and 0.410 ohm on the black-green secondary. At 1.0 kHz, 1.0 V open circuit, the primary measures 21.4 H (132.0 Kohm) and the secondary 27.36 mH (680.1 ohms). Primary leakage inductance is 13.54 mH.

Performance per the drawing is 70 Hz to 15 kHz (0/-1.0 dB reference @ 1 kHz) with distortion under 1% at 70 Hz. The winding is paper, and materials and design specifications were kept as close as possible to the original part to preserve the stock tone, in a unit constructed to look similar to the factory original where possible.

The open-style transformer has 9 in minimum leads: blue and brown primary with red centre tap, black common and green 8 ohm secondary. Drawing dimensions are A 3.7100 in, B 2.4000 in, C 2.308 in and D 3.130 in. It is rated 1500 VRMS and -40 to 105 degC, RoHS and REACH compliant, with a shipping weight of 1.6 lbs (0.73 kg).