Hammond 117F4 70V 4W Line Matching Transformer, 8 Ohm Speaker

The 117F4 is a 70 volt line matching audio transformer from the 117 Series (Audio Sound Distribution Line Matching). It couples a 8 Ω loudspeaker to the 70 V line output of a distribution amplifier, for use in audio sound distribution systems. It is the 8 ohm, 70 V, 4 W model; the 117E4 covers 3.2 ohm speakers and the 117K4 covers 25 V lines.

The transformer is rated at 4 watts and offers 5 primary power taps — 4 W, 2 W, 1 W, 1/2 W, 1/4 W — marked in watts on the part, so installers can pick the tap that matches each speaker's power without calculation. The manufacturer notes that the total power requirements of the speakers should not exceed the rated power of each transformer or the rated power of the amplifier.

Typical performance from the 117F4 drawing: frequency response 100 Hz to 10 kHz (1 dB reference @ 1 kHz), distortion less than 1.25% at 100 Hz at maximum power, insertion loss under 2 dB, dielectric strength 500 VRMS and a temperature range of -40 to 105°C. DC resistance is 336 Ω (COM - 1/4 W) on the primary and 0.40 Ω on the input (speaker) winding.

Mounting is horizontal on a channel bracket with two 0.187" diameter holes on 2.38 in (60 mm) centers. Overall dimensions in the series table are A 2.81 in (71 mm), B 1.50 in (38 mm), C 1.69 in (43 mm) and D 2.38 in (60 mm). All connections are solder lugs that are also suitable for slip-on jumper connections. Listed weight is 0.6 lbs (shipping weight 0.6 lbs (0.27 kg)), and the part is RoHS and REACH compliant.