Hammond 850QA Sealed 10K/40K Isolating Audio Transformer

The 850QA is a sealed, broadcast-quality 850A Series audio transformer for interstage or isolating use at high impedance. Both primary and secondary are a nominal 10K/40K ohms, so it isolates one high-impedance stage from the next without stepping impedance. Nominal winding resistance is 4890 ohms primary and 4980 ohms secondary (+/- 20%).

Across the series, frequency response is +/- 0.5 dB max. from 20 Hz to 20 kHz, insertion loss is approximately 1 dB, maximum power level is +15 dBm with the specified characteristics, and distortion is approximately 1.5% at 20 Hz under full power. Because this model has a winding above 5K ohms, the series notes it may be down 1 dB at 20 kHz. The sealed case and internally wax potted core are intended for stable characteristics and long life.

An electrostatic shield between primary and secondary is connected to the green lead. Humbucking construction and balanced split windings on both sides add circuit versatility, and the primary may be used as the secondary and vice versa for impedance matching.

The case is deep-drawn steel with a tin plated finish, sealed, and fitted with two 6-32 mounting studs; mounting hardware is included. Leads are a minimum of 4" long. The listed overall dimensions are A 1.20 in (30 mm), B 1.70 in (43 mm), C 1.65 in (42 mm) and D 1.32 in (34 mm). The 850QA is RoHS and REACH compliant, with a listed shipping weight of 0.4 lbs (0.18 kg) and UNSPSC 39121301.