Hammond 106R 48 CT to 8 Ohm Output Audio Transformer, 1.5 W

The 106R is the 8 ohm counterpart to the 106Q in the 106 Series: a miniature output transformer with a 48 ohm centre-tapped primary and an 8 ohm secondary. It suits compact PC board amplifiers that need to drive an 8 ohm load from a low-impedance push-pull stage.

Output rating is 1500 mW with 1 dB insertion loss and a -1 dB roll-off at 170 Hz; the drawing states a frequency response of ±1dB 170Hz to 20KHz at 20dBu. Maximum primary DC is 32 mA. The ordering table lists 2.4 ohms primary and 0.7 ohms secondary DC resistance (+/- 15%), while the drawing breaks this down as 1.00 ohms (pins 1-2), 1.01 ohms (pins 2-4) and 540 mOhms (pins 5-8). Primary inductance across pins 1-4 is 49.5mH (445 ohms) and leakage inductance is 248uH at 1V, 1KHz.

Construction is rugged black epoxy potting that produces a completely sealed unit able to withstand severe environmental conditions, including those of MIL-T-27 (Grade 5, Class S). Centre-tapped windings use a bifilar technique for balanced resistive and capacitive characteristics, and the series carries a peak working voltage rating of 200V. Per the part drawing it also has a 500V RMS dielectric strength, a 105°C temperature class and a 50,000 ft. maximum operating altitude.

It mounts directly to a printed circuit board on square pins (0.025" square typical); where a connection is not used, no pin exists. It is REACH and RoHS compliant. Mechanical outline is drawing Figure 8; the drawing gives a weight of 1.44 oz. and the shipping weight is 0.09 lbs (0.04 kg).