Hammond 143D 200K to 1000 Ohm Chassis Mount Input Audio Transformer

The 143D is a 143-146 Series input audio transformer that couples a 200K ohm primary to a 1000 ohm secondary. It is built for input applications fed from a very high impedance source, packaged as a small open type part for chassis mounting.

Output is rated at 25 mW, and the series table lists the primary D.C. current as 0 mA. D.C. resistance is 4500 ohms on the primary and 30 ohms on the secondary, both +/- 15%.

Mechanically, the 143D is a small, economical open type transformer with a two hole horizontal bracket for chassis mounting and overall dimensions of A 1.26 in (32 mm), B 0.69 in (18 mm), C 0.69 in (18 mm) and D 1.06 in (27 mm). It uses insulated, color coded flexible leads at least 4" long, and net weight is 0.5 oz. Where a P.C. board mounted version of this style is needed, the manufacturer refers to the 148 and 149 series.

Frequency response is 150 Hz to 15 kHz within +/- 1 dB, referenced to 1000 Hz. The manufacturer notes that operating at impedances below nominal lowers power capability and frequency spectrum proportionately, while higher impedances raise them. It follows schematic 1 in the series table and is listed as RoHS and REACH compliant (UPC 623980191003).