Proper Guitar Grounding
All ToneStylers have one RED signal wire. Connect this wire directly to the pickup's hot signal wire, or to the output of a pickup selector switch at 100% signal strength, before the signal has passed through any volume pots. Do not connect a ToneStyler to the output of any volume pot.
500 and 800 series ToneStylers have one CLEAR ground wire which is electrically common to the cable's internal copper shield wire, the ToneStyler's metal casing and mounting bushing... and after installation, to the guitar's mounting surface. The cable's internal copper shield wire has been intentionally clipped off the open end of the shielded cable; it's unnecessary to solder it to the ground, as it's already soldered to the ToneStyler's CLEAR ground wire. Just solder the CLEAR ground wire to the pickup ground, and you're done!
300 and 400 series ToneStylers have one GREEN or BLACK ground wire. For some older models, a second stranded copper shield wire was also furnished. If two ground wires have been provided on your 300 or 400 series ToneStyler, just solder both grounds together to the same ground point shown in the diagram... usually the metal case of a volume pot.
General suggestions for proper guitar grounding:
Most guitars feature a control mounting surface covered in a metallic foil, a metallic paint, or use a conductive plate that is grounded. These efforts are always helpful, but none are guaranteed to fully-ground your controls and circuits for optimal performance and hum reduction. For example, a metal control plate may appear to provide a perfect ground surface for mounting controls, but the metal may be clear-coated or anodized to prevent oxidation; this coating can prevent the controls from being properly grounded. For best results, always solder ground wires between the metal pot cases or bushings, and the ground terminals of switches and jacks, to a single common ground point, usually chosen as one volume control's casing.