Hammond 125FSE 20 W Single Ended Tube Output Transformer, 90 mA

The 125FSE is a 20 watt universal single ended tube output transformer, designed for general purpose or replacement use (not Hi-Fi) in single ended tube output circuits. It is aimed at builders of larger single ended amplifiers who need higher power and DC current handling in a flexible multi-impedance part.

The 125FSE is rated for up to 90 mA DC bias. Like all 125SE models it uses a butt stacked 29M6 steel core with an air gap to reduce D.C. core saturation. The primary (BLU - BRN) reflects 10,000, 5,000 or 2,500 ohms according to the secondary lead used with 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

Typical drawing data shows 105.0 ohms primary DCR, 6.41 H primary inductance and 40.50 kOhm primary impedance at 1 kHz, 1 V, with secondary DCR from 141 milliohms (black - orange) to 342 milliohms (black - white). Frequency response is 100 Hz - 15 kHz at full rated power, dielectric strength 1500 Vrms, and the temperature range -40 to 105C.

The 125FSE is open style with minimum 12 inch primary and secondary leads. Its dimensions are A 3.76 in (96 mm), B 2.52 in (64 mm), C 3.15 in (80 mm), D 3.13 in (80 mm) and E 2.25 in (57 mm), with 0.20 in (5 mm) x 0.38 in (10 mm) mounting holes. It weighs 4.5 lbs per the series table (shipping weight 4.75 lbs / 2.15 kg), is made in Canada and is RoHS and REACH compliant.