This is a used Russound SS-4.2 Impedance Matching 4-Pair Speaker Selector.

It is in very good condition. All connectors, buttons, and switches work as normal.

Features:

- Play up to 4 pairs of speakers simultaneously

- Impedance-matching protection circuitry ensures that your amplifier or receiver operates at a safe load

- Power handling: 100 watts per channel

- Accepts up to 12-gauge speaker wire

Overview: The Russound SS-4.2 Speaker Selector allows you to switch up to four speaker pairs connected to a stereo amplifier. Each pair of speakers can be turned on or off through individual front panel switches. It provides switchable built-in impedance matching or can be used with impedance matching volume control. The SS-4.2 is designed for use with 8-ohm loudspeakers.

Impedance Matching Protection: When used with multiple speaker pairs, the impedance matching circuitry lets you operate the system safely with automatic overload protection. When connecting more than one pair of 8 ohm speakers to the speaker selector, the rear panel impedance switch should be placed in the "In" position. If using impedance matching volume controls (such as ALTx-2 or LPTx-2), the switch should be in the "Bypass" position.

Amplifier Requirements: When using internal impedance matching (switch set to "In"), a 4-ohm stable amplifier is required. When using external impedance matching volume controls (switch set to "Bypass"), a 4 to 8 ohm stable amplifier may be used. You should use only the Amplifier "A" speaker outputs when the SS-4.2 is used. "B" speaker outputs should not be used.

Connections: The SS-4.2 features spring clip speaker terminals that can accommodate up to 12-gauge wire. For most applications, stranded 16-gauge speaker wire is recommended. For runs of over 100 feet, 14-gauge is recommended, while 12-gauge can be used for runs of up to 200 feet.

Performance: The speaker selector is designed for use with amplifiers with a power output of up to 100 watts per channel RMS (200 watts per channel peak. The frequency response is 20Hz to 20kHz (+/- 0dB).