Hammond 148R 20000 Ohm Driver Audio Transformer, 50 mW PCB Mount

The 148R is the highest primary impedance driver in the 148 Series, stepping a 20000 ohm primary down to a 250/1000 ohm secondary. It is intended for designers coupling a very high impedance audio stage into a low impedance load on a printed circuit board, where a small open frame part keeps the layout compact.

Like every unit in the 148 Series, it uses an economical, open type, horizontal bracket construction with pin-type terminals (0.25" length and 0.025" square) for P.C. board mounting. The windings are bifilar wound for balanced capacitive and resistance characteristics on pin bobbins that suit a standard 0.2" grid, and each unit is insulation tested at 250V rms. Pins are not labeled on the part; a dot marks pin 1 and the remaining pins follow the schematic figure.

The 148R is rated for 50 mW output with a maximum primary D.C. current of 2.4 mA. Its D.C. resistance is 2230 ohms on the primary and 123 ohms on the secondary (+/- 15%, measured with multiple windings in series). Frequency response is 200 Hz to 15 kHz (+/- 1 dB, referenced at 1 kHz) and insertion loss is less than 1/2 dB, while total distortion is approximately 2% at 200 Hz for drivers, decreasing at higher frequencies. Connections follow schematic figure 2, and the split secondary provides both 250 and 1000 ohm options.

The 148 Series has a net weight of 0.6 oz.; the 148R ships at 0.05 lbs (0.02 kg). It is RoHS and REACH compliant, UPC 623980198309.