Wiring & diagram Info

     In the operation is still a lot of these "dinosaurs" of the mid 90s. A characteristic feature of built-in amplifiers such devices - they are designed for load 2 ohms and have a good supply of power. This is due to the fact that in the middle position fader front and surround speakers are connected in parallel. However, to use them in conjunction with acoustic component is impossible. The reason is simple - the introduction of the fader increases the output impedance of the amplifier, which leads to a change in crossover. Therefore, the only option enhancers such devices with modern acoustics - dual channel configuration, with the fader excluded from work.

     In this version, you can add a subwoofer to include it in a "mixed-mono". Since the relationship between the levels regulate front speaker and subwoofer impossible, depending on the sensitivity applied to select one of the heads of connectivity options.

     Option A is used in the case where the sensitivity of the front speakers 3-5 dB higher than that of the subwoofer. In this embodiment, they are connected to the amplifiers are not bridged, and the usual way, and the power supplied to them is not more than 7 w / 4 ohms. To obtain sufficient volume of the front acoustic desirable to use high-sensitivity head about 91-93 dB. Pay attention to their phasing - one of the "poluusiliteley" inverting the second - non-inverting. HPF cut formed by the capacitors C1 and C2 can be chosen arbitrarily, but the presence of capacitors is crucial - they do not miss out on the dynamics of the DC component from the output amplifiers. Front head shown conventionally broadband, but they may be coaxial or component.

     Option B is used in nearly all heads of sensitivity. The presence of capacitors C1, C2 for the normal functioning is not necessarily because it is used in a bridge connection. In the absence of capacitors in the passband head subwoofer filter work in parallel. This reduces the load impedance to 2 ohms, but the amplifier is designed. Subwoofer in both cases the second-order filter (C3L1R1).

The bi-directional sequencer uses a 4 bit binary up/down counter (CD4516) and two "1 of 8 line decoders" (74HC138 or 74HCT138) to generate the popular "Night Rider" display. A Schmitt Trigger oscillator provides the clock signal for the counter and the rate can be adjusted with the 500K pot. Two additional Schmitt Trigger inverters are used as a SET/RESET latch to control the counting direction (up or down). Be sure to use the 74HC14 and not the 74HCT14, the 74HCT14 may not work due to the low TTL input trigger level. When the highest count is reached (1111) the low output at pin 7 sets the latch so that the UP/DOWN input to the counter goes low and causes the counter to begin decrementing.

 When the lowest count is reached (0000) the latch is reset (high) so that the counter will begin incrementing on the next rising clock edge. The three lowest counter bits (Q0, Q1, Q2) are connected to both decoders in parallel and the highest bit Q3 is used to select the appropriate decoder. The schema can be used to drive 12 volt/25 watt lamps with the addition of two transistors per lamp as shown below in the section below titled "Interfacing 5 volt CMOS to 12 volt loads"