Spectrum Series II Bass—SPB311


This is the wiring diagram for a SPB311. We presume it is a 1988 model as it has 24 frets and a beveled heel. The IC (GL358 dual operational amplifier) on the PCB is an obsolete part and may be hard or costly to obtain. If it needs replacing, an LM358 may be used instead.

  • The switches are DPDT (Active on/off) and 4PDT (Dual tone switch)
  • The pickup selector switch is a standard SPDT (On/on/on) switch
  • The volume pot is 500k log
  • Both the active and passive tone pots are 500k linear
  • The tone capacitor is 0.047 microfarad Mylar
  • Pickups:
    • Neck -Magnabass IV , 6.45k per coil
    • Bridge -Magnabass V ,  6.59k per coil

Only these wires are shown in the same colour as they are on the guitar :

  • wires from the pickups
  • screened leads
  • earth wire to bridge
  • positive lead to battery box
  • the dark blue wires to the pickup switch, volume control and active circuit PCB

Different colours are used for all the other wires to make the diagram readable. On the guitar, they are all dark blue:

click to enlarge

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