Hammond 145O 15000:200CT Ohm Driver Audio Transformer, Chassis Mount

The 145O is an open-frame audio driver transformer that steps a 15000 ohm primary down to a 200 ohm center-tapped secondary, supplied 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. Its primary carries up to 4 mA of D.C. current and has a D.C. resistance of 850 ohms, while the 200 ohm ct secondary measures 10 ohms (both +/- 15%). On the manufacturer's part page the short description for this part reads simply "TRANSFORMER". 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 145O 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.