Hammond 1750R 100W Yorkville/Traynor Output Transformer, 4/8/16 Ohm

The 1750R is a 100 watt push-pull output transformer for tube guitar amplifiers, designed as a drop-in replacement for original units such as Yorkville/Traynor 98694 (similar to A1301, reference only). The series ordering table lists it as "Old #89694" in both its Yorkville/Traynor and Gibson output transformer tables.

It pairs a 2,000 ohm centre-tapped primary (brown and blue with red centre tap) with 4, 8 and 16 ohm secondary taps. Typical DC resistance is 25.72 ohms blue-brown on the primary and 0.222 ohm black-orange on the secondary. At 1.0 kHz, 1.0 V open circuit, the primary measures 4.84 H (31.2K ohm), with secondary readings of 16.20 mH (117.05 ohm) black-green, 31.28 mH (219.30 ohm) black-yellow and 58.48 mH (400.60 ohm) black-orange. Primary leakage inductance is 11.37 mH.

Frequency response is 50 Hz to 12 kHz (0/-1 dB reference @ 1 kHz) and distortion is under 1% at 50 Hz. The paper-wound unit was built with materials and design specifications kept as close as possible to the original to preserve the stock tone.

The open-style frame has 9 in minimum leads stripped 0.5 in. Drawing dimensions are A 3.750 in, B 3.936 in, C 4.560 in max, D 3.000 in and E 2.813 in, with G 0.203 x 0.375 in. Ratings are 2250 VRMS and -40 to 105 degC. It is RoHS and REACH compliant and ships at 7 lbs (3.18 kg).