The Modulator range evolved from the Hayman "Modular" which was built by Shergold prior to launching their own brand guitars.
Designed by Bob Pearson, they are, as far as I know, unique amongst guitars in having electronics modules that are removable and interchangable.
Modules can be shared across the range, with six strings, twelve strings and basses all using the same modules.
I have scans of an original information leaflet for the Modulators which also covers most of what I've written below.
To accomodate the more exotic Stereo and Quad modules, the output jack sockets on all Modulators are of the stereo type, and are wired specially to cope with this. All the other modules create a mono signal, which will come out of the Left channel if a stereo plug is used.

Circuit diagrams for six of the seven production modules are now available; the most recent addition being the Stereo module. I may even have a Quad eventually...watch this space...

Note that these are not scans of original Shergold schematics - they have been reverse engineered from the modules, so there may be the odd mistake in there - I've caught a few myself, but please let me know if something looks wrong...
The same treatment is beginning to be given to the other non-Modulator models' circuitry on the Models page, given access to original examples and the time and patience! The modules are ideal for this sort of inspection due to their accessibility. I expect the wiring on other models to be practically identical to that in the modules, so they are probably the best starting point.

If there are any suitably skilled people out there with a Shergold that they can work out the circuits for, you are welcome to contribute to the cause - all assists will get an acknowledgement on the circuits they have worked on.

Click on the name of a module to jump to the full description and schematics...

Provides the basic T*lecaster type setup. This module is the one that all Modulators were supplied with from the factory. Three way pickup switch: Bridge, Bridge and Neck in parallel, Neck Master Tone Control Master Volume Control

Circuit Diagram

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Same as the Basic Module, but with the option of phasing. Operating the phasing switch connects the individual coils in each humbucker pickups either in phase or out of phase with each other. Three way pickup switch: Bridge, Bridge and Neck in parallel, Neck Two way phasing switch: labeled "In" and "Out" Master Tone Control Master Volume Control Thanks to Jerome for spotting the phasing switch error on the first version!

Circuit Diagram

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More advanced module that provides similar switching to L*s P*ul guitars, but with one feature I have never seen on any other production guitar; the option to completely bypass the tone and volume circuits. Even with the controls in the highest position there will always be some signal leakage, and hence loss of tone. With Module 3, putting the bypass switch to 'Solo' cuts the tone and volume controls from the circuits and effectively wires the pickups directly to the output jack. This is especially noticeable with the neck pickup as it gains a huge amount of 'depth' when switched in. Three way pickup switch: Bridge, Bridge and Neck in parallel, Neck Two way bypass switch: labeled "Rhythm" and "Solo" Tone Control for each pickup Volume Control for each pickup

Circuit Diagram

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Plays out through the standard Modulator jack socket, which is stereo on every one built, but is often replaced with a mono one when the socket breaks down as most owners don't have the stereo or quad modules. This module is nearly identical to Module 3 (in fact only a single wire is different!). The stereo output is produced by splitting the pickup output from the neck and bridge pickups to the left and right channels of the jack socket. Three way pickup switch: Bridge, Bridge and Neck in parallel, Neck Two way bypass switch: labeled "Rhythm" and "Solo" Tone Control for each pickup Volume Control for each pickup

Circuit Diagram

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Switch Heaven! This is an amazing piece of circuitry which has taken many hours and a lot of scrap paper to work out! It's only by working out the circuit diagrams, that I've been able to find out what each switch does - all three switches are labelled simply "1,2,3"! This module is especially useful in basses, and for getting some really interesting clean amp rhythm sounds in the six string guitar. Three way pickup switch: Bridge, Bridge and Neck in parallel, Neck Three way Neck pickup coil switch: single coil, humbucker out-of-phase, humbucker in-phase Three way Bridge pickup coil switch: single coil, humbucker out-of-phase, humbucker in-phase Tone Control for each pickup Volume Control for each pickup

Circuit Diagram

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Information culled from the 1982 review of the Moduator in "Electronics and Making Music" magazine until I get hold of one of these myself! Gives the option of a separate amplifier output for each coil in each pickup. Three way pickup switch: Bridge, Bridge and Neck in parallel, Neck Three way Neck pickup coil switch: Function unknown... Three way Bridge pickup coil switch: Function unknown... Stereo Tone Control for both pickups Stereo Volume Control for both pickup Stereo jack socket on control plate

Circuit Diagram Not Available

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The module for grunge rockers! A simple single stage transistor amplifier of the sort in any first year electronics course which distorts the signal by two ways: clips (chops the tops and bottoms off) the signal, and has crossover distortion (lags when changing from negative to positive signal and vice-versa). The increase in overall output level will also drive the input stage of the amplifier much harder causing it to clip and overdrive. It is powered by a single PP3 (9 volt) battery squeezed into the module cavity with the switching circuitry. Trivia corner: this module has the switch and pot labels printed upside down! The labels are readable looking down from the top - all the other modules read in the same orientation as the scratchplate text. Three way pickup switch: Bridge, Bridge and Neck in parallel, Neck Two way boost switch: labeled "Normal" and "Boost" Boost Volume Control Tone Control Volume Control

Circuit Diagram

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These were built to order or provided as blank plates with just the pickup and jack connection blocks, and fixing bolt, for the owner to build their own module.

Circuit Diagram Not Available

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