Hammond 1750E 15W Tweed Deluxe Output Transformer, 8 Ohm

The 1750E is a push-pull tube guitar amplifier output transformer built as a drop-in replacement for the original unit in Fender Deluxe 5E3 and Princeton amplifiers. It is listed as similar to Fender part number 50246 and suits amp technicians, restorers and builders who need a stock-style replacement for a 15 watt tweed-era circuit.

Electrically, the 1750E matches an 8,500 ohm centre-tapped primary to a single 8 ohm secondary and is rated at 15 W output. Typical DC resistance is 150.0 ohms on each primary half (red-brown and red-blue) and 0.450 ohm on the black-green secondary. At 1.0 kHz, 1.0 V open circuit, the blue-brown primary measures 24.0 H (145K ohm) and the secondary 822 mH (520.8 ohm); primary leakage inductance is 469.2 mH.

Following the series design brief, the materials and design specifications were kept as close as possible to the original part to preserve the stock tone, and the unit was constructed to look similar to the original factory transformer where possible. It uses a bobbin winding in an open-style frame.

Installation is straightforward: all primary and secondary leads are at least 9 in long, with brown and blue primary leads, a red centre tap, a black common and a green 8 ohm secondary lead. Drawing dimensions are A 3.250 in, B 2.085 in, C 1.995 in and D 2.813 in. The part is rated for 1500 VRMS dielectric strength and -40 to 105 degC, and it is RoHS and REACH compliant. Shipping weight is 1.1 lbs (0.50 kg).