Mark lists the serial numbers of guitars that use the older style, #601 (or part number 22380601) divided pickups: G-202 before serial no. For the G-303, G-505 and G-808, each string needs two resistors changed, one effecting the synthesizer signal, and the other effecting the hex fuzz signal.
The G-202 has a different hex fuzz circuit, so only six resistors need to be changed.
When switching from the 80 ohm (narrow) to 900 ohm (wide) pickup, there is a 10:1 increase in impedance, likewise, it is necessary to change the negative feedback loop resistor by a similar ratio, from 330K to 33K, and from 1 M to 100K.
Mark also mentions that the pick guard must be slightly enlarged to accommodate the wider pickup, but only on the G-202 and G-505, the only guitars with pickguards.
The other vintage controllers, the G-202 and G-505, are well-built, fine guitars.
But they cannot escape the feel of being really well made Fender copies, no matter how nice they are. The more expensive G-808 has through-neck construction and other nice features, like gold hardware.
From looking at the version "A" photo, it appears the one op-amp is used per string to both amplify the signal and create the hex fuzz sound.
If you look at IC6, at the top of the version "B" and "C" card, you can see resistors just to the left of the chip creating gain in the negative feedback loop, and additional diodes just to the right side of the chip for generating fuzz. After years of working with Roland vintage electronics, I finally noticed that there were two variations on the familiar hex pickup.
One pickup is small, with an impedance of 80 ohms, and the other pickup is slightly larger, with an impedance of around 900 ohms.
For my purposes, I labeled these pickups as "wide" or "narrow." One pickup is around 10 mm wide, and the other is about 12 mm wide.
In Los Angeles I have seen jazz players using the G-303 plugged straight into a Polytone amp, just for the sound and playability of this great axe.