Hammond 145P 20000:1000CT Ohm Chassis Mount Audio Driver Transformer

The 145P is an open-frame audio driver transformer with a 20000 ohm primary and a 1000 ohm center-tapped secondary, built on a two-hole horizontal bracket for chassis mounting. It belongs to the 143-146 Series of audio chassis-mount transformers and is intended for engineers, technicians and OEM builders who need a signal-level driver transformer between amplifier stages.

Electrically, it is rated for 135 mW output. The 20000 ohm primary is rated for 3.5 mA of D.C. current and measures 1180 ohms D.C. resistance; the 1000 ohm ct secondary measures 50 ohms (both +/- 15%). The 145R shares this primary with a 2000 ohm ct secondary. The series specification sheet gives a frequency response of 150 Hz to 15 kHz (+/- 1 dB, reference 1000 Hz). When it operates at impedances below nominal, power capability and the frequency spectrum are proportionately lower; at higher impedances they are proportionately higher.

Construction is small, economical and open, with a two-hole horizontal mounting bracket. Leads are insulated, color-coded and flexible, at least 4 in long for the 145 Series. Overall dimensions from the series table are A 1.63 in (41 mm), B 0.88 in (22 mm), C 0.81 in (21 mm) and D 1.38 in (35 mm), and the series sheet gives a net weight of 1.4 oz for 145 Series parts.

The 145P is listed as RoHS compliant and REACH compliant. For a similar transformer designed for PC board mounting, the manufacturer refers to the 148 and 149 series.