Hammond 109K 1.5K:600 Ohm Center-Tapped 2W Potted Audio Transformer

The 109K is a miniature epoxy potted audio transformer from the 2 W-rated 109 Series, built for printed circuit board mounting. It matches a 1.5K ohm center-tapped primary to a 600 ohm center-tapped secondary with a 1.58:1 turns ratio, for feeding a 600 ohm line from a 1.5K ohm stage. Designers of audio input, line matching, isolation and output stages will find it a compact, board-level way to add transformer coupling.

Nominal impedances are 1.5K ohm CT on the primary (pins 1-3) and 600 ohm CT on the secondary (pins 4-6). The ordering table lists D.C. resistance of 105 ohms primary and 60 ohms secondary (+/- 20%) and a maximum D.C. unbalance of 4 mA. The part drawing gives typical values of 102 Ω (51Ω/51Ω) primary DCR, 2.436 H primary and 1.011 H secondary inductance, 6.68 mH leakage inductance, a 1.58:1 turns ratio and 100 Vrms dielectric strength.

The series is rated 2 watt (+/- 1.5 db, 300Hz. - 50 KHz.), and the 109K drawing lists a power level of 2.0W from 300 Hz to 50 kHz with typical output power of 2 W. Frequency range is 300 Hz to 50 kHz +/- 1.5 dB at +0 dBm and 300 Hz to 50 kHz +/- 1.5 dB at +27 dBm, measured with no D.C. saturation. Power ratings are maximum at the lowest frequency, and the secondary may be used as the primary and vice versa.

Construction is rugged epoxy potting in a black molded case, producing a completely sealed unit, with pin type P.C. board terminals of at least 0.187" length. The part withstands soldering for 10 seconds at 260 °C, is rated for 85 °C maximum ambient, and the casting epoxy has a workable range of -40 °C to +105 °C. It is RoHS and REACH compliant, made in Canada, and ships at 0.1 lbs (0.05 kg).