Hammond 1750S 25W Traynor Base Mate Output Transformer, 8 Ohm

The 1750S is a 25 watt push-pull output transformer for tube guitar amplifiers, designed as a drop-in replacement for original units such as the one in the Traynor Base Mate YBA-2B (similar to A1339, reference only). It appears in both the Yorkville/Traynor and Gibson output transformer tables of the series ordering guide.

It matches a 5,100 ohm centre-tapped primary to an 8 ohm secondary. Typical DC resistance is 380.0 ohms brown-blue on the primary and 0.751 ohm black-green on the secondary. Measured at 60 Hz, 10.0 V open circuit, the blue-brown primary inductance is 56.4 H (23.4 KOhm), and leakage inductance at 60 Hz, 10.0 V short circuit is 11.37 mH.

Frequency response is 50 Hz to 12 kHz (0/-4 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, and constructed to look similar to the factory original where possible.

Open-style construction provides 12 in minimum primary and secondary leads. Drawing dimensions are A 3.688 in, B 2.120 in max, C 2.308 in, D 3.125 in and G 0.187 in. It is rated 1500 VRMS and -40 to 105 degC, is RoHS and REACH compliant, and has a shipping weight of 7 lbs (3.18 kg).