Hammond 125ESE 15 W Single Ended Tube Output Transformer, 80 mA

The 125ESE is a 15 watt universal single ended tube output transformer for general purpose or replacement use (not Hi-Fi). It suits builders of higher-power single ended amplifiers and technicians who need a replacement that can match several plate loads and speaker impedances.

With a maximum DC bias of 80 mA, this model uses the 125SE Series' butt stacked 29M6 steel core with an air gap to reduce D.C. core saturation. Its primary (BLU - BRN) presents 10,000, 5,000 or 2,500 ohms depending on the secondary lead used against the black common:

• WHT: 32 ohms at 10,000, 16 ohms at 5,000 or 8 ohms at 2,500 ohm primary
• YEL: 16 ohms at 10,000, 8 ohms at 5,000 or 4 ohms at 2,500
• GRN: 8 ohms at 10,000 or 4 ohms at 5,000
• ORG: 4 ohms at 10,000

The series primary winding data for the 125ESE lists 5.43 H minimum inductance and 103 ohms DC resistance (+/- 20%); the part page lists 9.58 H minimum and 90.6 ohms. Typical drawing values are 103.0 ohms primary DCR, 5.43 H inductance and 33.8 kOhm impedance at 1 kHz, 1 V. Frequency response is 100 Hz - 15 kHz at full rated power, with 1500 Vrms dielectric strength and a -40 to 105C range.

It is open style with primary and secondary leads at least 12 inches long. Dimensions are A 4.50 in (114 mm), B 2.36 in (60 mm), C 2.94 in (75 mm) and D 4.00 in (102 mm), with 0.19 in (5 mm) mounting holes, and it weighs 3 lbs (1.36 kg). The 125ESE is made in Canada and RoHS and REACH compliant.