Roland G-707 Guitar Synthesizer Controller

Version History - The LEDs that never happened:

Unlike the previous Roland guitars, there is not much archaeological drama to the Roland G-707 guitar. The only differences I have detected are very minor changes to the guitar electronics package. The G-707 Service Manual Schematics makes note of LEDs, but provides no details. A closer look at the G-707 electronics card shows that there were provisions to include two power LEDS on the G-707 guitar, one for the positive 15 volt supply, and one for the negative 15 volt supply.

I have seen some cards with current-limiting resistors for the diodes in place, and some with them left off, while the silk-screening still shows the LED options. Consider this, if the G-707 was not striking enough, apparently Roland seriously thought about including glow-in-the-dark diodes on the guitar!

Resistors R16 and R17 for LEDs on the Roland G-707.	A different G-707 PC board without resistors R16 or R17 installed.	Screened on the back of R16 and R17 is the legend for "LED"
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Version History - Buffering the Volume Control Voltages:

The G-707 Service Manual Schematics also shows a buffering option the guitar and synth volume control voltages, but the buffering section, utilizing IC#5, is crossed out on the diagram. Like the diode variation, some cards do an operational amplifier in place, and some leave it off. IC#5 is a M5218, a popular inline dual operational amplifier. The M5218 is also used in the G-77, Ibanez IMG2010 and the Steinberger Roland-Ready guitars.

A little explanation: if the connected synthesizer "loads" the volume control voltage, the guitar synthesizer may have its volume reduced. So rather than reading a full 11 volts, the voltage may be reduced to 10 volts. Maximum volume on a vintage Roland synth is a control voltage of around 11 volts, expressed on pin 9, as synth volume, and on pin 10, as guitar volume. Pin 8 supports master volume, though this is mostly ignored by the vintage Roland synthesizers. The design of the Roland US-2 reduces the synth voltage slightly, meaning that synths played though a Roland US-2 are not as loud as they would be without the US-2.

By providing a buffer, it is less likely that the attached guitar synthesizer will reduce the synth volume output voltage. The G-707 was the first Roland guitar synth to incorporate a buffer circuit. The G-202/303/505/808 did not have a buffer circuit. Apparently Roland engineers had mixed feelings about the need to buffer the volume voltages, since as noted this feature is crossed off on the Service Manual Schematics schematic, though I have seen some G-707 cards with this feature in place.

G-707 Electronics Card with IC#5 Buffer Chip: S/N 2291385302.

G-707 Electronics Card without IC#5 Buffer Chip: S/N 2291385303.

A check of the Roland G-707 Service Manual Schematics shows that it only lists part number 2291385303. There is no mention of the earlier 2291385202 card which includes IC#5. Check out the photos of the STK-1 kit, based on the G-707 card. The STK-1 electronics card in the photos is the earlier version with both IC#5 buffer and the LED resistors.

G-707 electronics card with IC#5 (on left) installed with associated resistors.	A different G-707 PC board without IC#5 and associated resistors.	Roland G-707 Service Manual Schematics with IC5 shown as a buffer amplifier, but crossed out.
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Photos - Silver Finish:

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Photos - Silver Finish - Left Handed:

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Photos - Red Finish:

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Photos - Black Finish:

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Photos - Black Finish - Left Handed:

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Photos - White Finish - Custom with Steinberger Leg Rest:

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A few years back I picked up a G-707 very much in need of a new paint job. Rather than go with silver, red, or black, I had the guitar repainted in brilliant white. As an added bonus, the original owner had replace the leg rest with a Steinberger folding leg rest, which worked great!

Modification: Roland G-707 Hex Fuzz Output Upgrade

Click here to learn how to modify the Roland G-707 guitar to add hexaphonic output

• Add Hex Fuzz Output for Roland GR-300
• Easy-to-find Parts
• Maybe used with BX-13 series if Hex Fuzz output enabled

1984 Roland GR-700 G-707 Brochure - "We Design The Future:"

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