Yamaha BBT500-110 Owner's Manual - Page 10

Panel Controls and Connections * Total Impedance Whenever two or more speaker cabinets are connected to the unit, consideration must be given to the total impedance of the speaker system. Normally, a speaker cabinet has an impedance of 4, 8 or 16Ω. But when two or more speaker cabinets are used together, the total impedance will change according to the manner in which the cabinets are connected. ● Connecting in a Series Total impedance = 1st Speaker + 2nd Speaker + 3rd Speaker ... Connecting three 4Ω speaker cabinets in a series as shown below, results in a total impedance of 12Ω. As the BBT500-115's and BBT500-110's two speaker jacks are connected in a parallel circuit inside of the amplifier, adding a 4Ω external speaker to the 4Ω internal speaker will result in a total impedance of 2Ω. So in order to maintain a minimum impedance of 2Ω, an external speaker with an impedance of 4Ω or greater must be used. ● Connected in Parallel Total impedance = Connecting three 4Ω speaker cabinets in a parallel configuration as shown below, results in a total impedance of about 1.3Ω. 4 4 4 External Speaker Greater than 4 Ω Internal Speaker 4 Ω ● Attaching the Clamp Filter (For U.S. and Canadian models only) To protect against electromagnetic waves, attach the supplied Clamp Filter to the cable connecting the bass guitar to the amplifier's INPUT jack, and to the cable connecting the amplifier to an external speaker. * The cable connecting the internal speaker (SPEAKER 1 jack) is fitted with a Clamp Filter at the factory. * When attaching the clamp filter, wrap the cable once around the clamp filter as close to the BBT500 unit as possible. Cable Clamp Filter 10 Clamp Filter