ARP2600 - Fundamentals of Music Technology - Cyborgstudio.com

008 - SECTION ONE: GENERAL CONTROLSCONTROL VOLTAGES AND VOLTAGE CONTROLTo make a sound, different synthesizer modules are connected together using patch cords. However,the system that these modules use to control each other hasn’t been explained yet. Several differentsystems have come and gone over time. The ARP 2600 uses one of the earliest, and most primitive. (Itis one of the easiest to understand, though!) The 2600 uses a system called voltage control to sendsignals from one module to another.In a voltage control system, modules send out a raw electrical voltage that represents a value. Thegreater the voltage, the higher the value it represents. This voltage is called a control voltage. The termvoltage control is used to describe a system where these control voltages are used. Synthesizers do notuse a lot of voltage to send these signals, so one is never in danger of getting an electrical shock fromthe synthesizer, as long as the cabinet is not opened, which is fairly difficult to do, anyhow.Another way to remember these two, similar sounding terms is to remember that ‘voltage control’ isusually used as an adjective. It describes a synthesizer or a module of a synthesizer (e.g. the ARP 2600is a voltage controlled synthesizer). Meanwhile, ‘control voltage’ is a noun. One might say that acontrol voltage is being produced by a certain module.VOLTAGE CONTROL, PARAMETERS & VALUESVoltage control will be discussed in greater detail in the next section when it is possible to actually hearits effects. For now, students should just try to understand the basic concept. Earlier on in this sectionit was said that a parameter is something that can be changed, and the possible settings of that parameterare its possible values. On the ARP 2600, parameters are represented by control inputs. Values arerepresented by control voltages. By connecting a control voltage to an input jack, that value is assignedto whatever parameter the input jack represents. This will become clearer over time, especially when itappears again in the next section.KEYBOARD CONTROL VOLTAGEOne device that creates control voltages is the keyboard. It was mentioned earlier in this section that thekeyboard receives voltage from the cabinet through its connecting cable. However, the keyboard isalso returning several signals of its own, one of which is the keyboard control voltage. The higher thekey played, the greater the voltage the keyboard sends out. This voltage goes back to the cabinet andcomes out the Keyboard CV output jack on the front panel of the cabinet. This jack is located just abovethe multiple and can be seen in Figure 1-8 on page7. This voltage is then used to control the pitch of theoscillators, as will be explained in the next section.