300W Impedance Matching Screwless Rotary Knob Volume Control, Decora Style Wall Plate Snap On, White (Bone, Almond, Black, and Brown available) – SLK-300

Now you can match your decora style light switching with this innovative screwless volume control. All speakers have an impedance rating, typically 8 ohm for a pair of home speakers. To operate in the safest mode, most standard amplifiers and basic two-channel receivers are rated for an 8-ohm incoming load. To operate safely and consistently, the amp needs to see an 8 ohm load, and that’s where speaker selectors and impedance-matching volume controls come into play.

In a basic multi room system, only a Speaker Selector is used to connect the speakers to the amplifier/receiver. Not only does the Speaker Selector allow you to connect multiple speakers to the amplifier but also adds internal Impedance Protection which is enabled by a manual protection switch. Both our ISS and DSM series Speaker Selectors feature internal Resistors that protect the amplifier. The down side is that the power rating normally 140 watts is cut in half when the protection switch is enabled so rated at 70 watts with protection.

In a standard multi-room system (using Impedance Matching VC) you will typically have an amplifier/receiver, a speaker selector with 4 to 8 zones, and volume controls connected to all the speakers. Impedance-matching volume controls provide more precise protection for the amplifier/receiver versus the protection built into the standard speaker selector. Plus with the protection switch in the off position you will have the maximum power handling capability of the respective speaker selector. It is important that the protection switch is turned off when using the Impedance matching Volume Controls.

What Is Impedance Matching Volume Control?
Impedance is a measurement of resistance to alternating current. Speakers are specified by impedance, and a common value is 8 ohms. When you’re connecting multiple speakers to a receiver or amplifier, you need to stay above the amp’s minimum load requirements because going below the impedance rating can overheat or even damage expensive equipment. Volume controls such as the SLK300 have selectable impedance so you can match the impedance with the number of speakers being controlled with the capabilities of your amp. A basic multi-room system will typically have an amplifier/receiver, a speaker selector, four to eight pairs of speakers, and volume controls. Impedance-matching volume controls feature three settings depending on how many speakers you are connecting. For one to two pairs of 8-ohm speakers, the setting is 1/2x; for three or four pairs of 8 ohm speakers, the setting is 4X. Volume controls do not add gain (volume) to your speakers but simply attenuate the volume up or down. During setup, you'll set the source volume to its optimum level, then the volume control turns the sound down to inaudible levels.