User manual DLS BRXZM1E

[. . . ] DLS ZM1, Z-match General DLS Z-match is an impedance-matching transformer for speaker loads. It can be used for transforming up or down the output voltage from a car amplifier to the speaker/speakers. You may have had the problem that you want to connect two 4 ohm subwoofers in bridge mode to an amplifier. Since most amplifiers are 2 ohm stable this is impossible without destroying the amplifier. [. . . ] The speaker to the right plays with four times more power than the two others. 2 3. DLS Z-match: DLS Z-match can be described as a transformer with many taps (terminals). An ordinary transformer has a primary side and a secondary side. Primary 10 volt 100 turns 200 turns secondary 20 volt If you repeat the calculations you will find that: A four ohm speaker connected to the primary side, and an amplifier connected to the secondary side senses: On tap 1: On tap 2: On tap 3: On tap 4: 4 ohms 8 ohms , the impedance x 2 16 ohms, the impedance x 4 32 ohms, the impedance x 8 The transformer above has a primary side of 100 turns of heavy copper wire on an iron core, and a secondary side of 200 turns of not so heavy copper wire on the same core. This transformer transforms a primary voltage of for example 10 volts to a secondary voltage of 20 volts. If you connect 10 volts to the secondary side you will have 5 volts out on the primary side. If the transformer is designed to be used for audio frequencies, and for impedances of one up to 10 ohms it can be used to transform the impedance of a speaker to become higher or lower. If a 4 ohm speaker is connected to the primary side, the one with 100 turns, an amplifier connected to the secondary side will sense a speaker impedance of 16 ohms. This caculated with this formula: Zs = Zp x ( n2 / n1 )2 Zp is the impedance of the speaker connected to the primary side, in this case 4 ohms. n2 / n1 is the ratio between the number of turns on the secondary side (n2) and the number of turns on the primary side (n1) In this case the ratio is 200 turns / 100 turns = 2. This is also the ratio between the secondary voltage and the primary voltage, 20 volts / 10 volts = 2. Put the figures into the formula and the result is Zs = 4 x 2 x 2 = 16. If we connect our speaker to the secondary side instead, and calculate the impedance the amplifier sees when it´s connected to the primary side. Here the speaker impedance will be divided by four and the amplifier sees a 1 ohm load. With this simple transformer I can increase a speaker impedance by four times, or divide it by four. If you add two taps to the secondary winding, one at 100 turns, one at 141 turns and add some more turns it can be as below: Primary side: Tap 1 100 turns for ex. 10 Volt Secondary side: If you connect the speaker to the secondary side, and an amplifier to the primary side it will sense: (when the speaker is connected to the following taps) 0 and tap 1: 4 ohms, divided by 1 0 and tap 2: 2 ohms, divided by 2 0 and tap 3: 1 ohm, divided by 4 0 and tap 4: 0, 5 ohm, divided by 8 This is the principles behind the Z-match. The transformer described above is a transformer with separate primary and secondary windings insulated from each other. DLS Z-match is an auto-connected transformer with a single winding equivalent to the secondary winding above. In this way the power handling capacity is increased and it makes the transformer cheaper and not so heavy. The transformer losses will increase at frequencies over 10 kHz, especially when you use the x 8 terminal. This is normally no problem since the Z-match is mostly used for subwoofers. [. . . ] The amplifier load becomes "nicer". 1 ohm 1, 33 ohm 2 ohm 4 ohm 8 ohm 12 ohm 0-2 1-4 1-3 0-2 0-2 2-3 0-1 0-2 0-1 0-3 0-4 0-2 2 ohm 2, 22 ohm 2 ohm 2 ohm 2 ohm 2 ohm 5 Connections with amplifiers that can handle 4 ohm load in bridge mode, or 2 ohm in stereo mode. (2-ohm stable) This type of amplifiers is the most common. They are what we say "2 ohm stable". They can be loaded with 2 ohm in stereo and 4 ohm in mono bridge mode. [. . . ]