Megaswitches

1. Overview

Please check our overview of Megaswitches first before making a selection in the store!

All following circuits can be realized with the Megaswitch toggle switch as well as with the Megaswitch rotary switch, the respective circuit board is always the same!

Overview PDF

• You can find all switch plans and layout plans for Schaller switches and Megaswitches here.
• With these switches, the tonal possibilities of many electric guitars can be expanded quite significantly. They allow coil combinations in the pickups that cannot be obtained with the conventional standard switches.

Megaswitch S and T have the same circuit board/PCB; it is labeled S+T. All circuits/wiring diagrams in the following chapters for Megaswitch S and T can therefore also be used equivalently for T and S.

Instructions:

1. Soldering tags on the printed circuit are marked from 1-7/8/9 or from A-X.
2. Mount the switch so the PC (Printed Circuit) is facing to the strings. 

• This applies to normal right-hand guitars. On left-hand guitars, the plated side faces away from the strings.
• These switches substantially broaden the range of possible sounds on electric guitars. They allow coil combinations on the pickups which are impossible to create using conventional standard switches.
• Installation is simple – neither woodwork nor drill holes are required on the back plate . Simply remove the wires from the old switch by heating the connections with a soldering iron, then remove the switch and replace it with the Megaswitch. Solder the wires according to the diagram. Finished!
• The solder connections on the circuit board are marked from 1 to 7/8/9 or from A to X.
• In the normal right-handed guitars, the switch is mounted so that the printed circuit board faces the strings. In left-handed guitars it points away from the strings. 

There are six different types to choose from: E, E+, S, P, M, T.
This allows a variety of different sound possibilities to be achieved.

2. Which Megaswitch is suitable for which guitar type?

Select your current pickup configuration here:

3. List of possible applications:

4. Explanation of circuits

Potentiometer connections:

• L = Left position
• S = Wiper
• R = Right position

The Megaswitch switch symbols illustrate the following: blacked out points are real contacts and open points are switch positions which do not refer to contact function. The switch is in position 1 when the lever is positioned in the direction of the bridge or the rotary knob is turned all the way to the left.

The wiring diagrams are illustrations of right-hand guitars, in which case the Megaswitch is built with the plated side facing the strings. Please note that left-hand designs are not quite reverse images. Here, the switches are positioned with the plated side facing away from the strings and the potentiometer (control knob) connections are reversed, since left-hand versions (i.e. "logarithmically negative” versions) and the control knobs with numbers in reverse order to match them, are rare.

There is no difference between right-handed and left-handed guitars in the rotary versions.

The electrical switch diagrams per se are more or less the same for both left and right-hand models.

5. Correct phasing of coils

When the coils of various pickups are combined on a single instrument, they sometimes fail to work together, i.e. they operate out of phase. The resultant sound is very thin and hollow and the bass end lacks considerably, which is not necessarily desirable! When the pickups on a guitar are all made by the same manufacturer, they usually (but not always) work correctly. Complications are quite common when the pickups are made by different manufacturers. If you want to avoid this prior to installation, it is wise to inform yourself of the technical characteristics of the pickups you intend to combine. Unfortunately, manufacturers don’t usually make such information readily available to end-users.

In technical jargon, so-called hot and cold connections are often referred to. The term ‘hot’ connections refers to wires that carry signal. If you touch them with your finger, your amp buzzes. Conversely, cold connections are those which are connected to the earth/ground, the zero potential, - the outer contact of the jack socket, the potentiometer housing, inner shielding, strings…If you touch these, no buzz comes out of your amp. Principally, hot and cold connections can only be clearly defined on pickups which have a single-core insulated cable, i.e. many old Humbuckers and single coils type P90 / P94.

However impractical the hot wire is often referred to as plus and the cold wire is referred to as minus. These terms originate from the world of direct current. By contrast, pickups only use alternating current.

Nevertheless, pickups do have a kind of electrical polarity or operating direction. When a single pickup operates alone, polarity is insignificant. However, as soon as two or more are in operation this polarity becomes important. Specifications such as "winding start" and "winding end" ("Start", "Finish") - as in some tables presented on the Internet - do not work in practice because the winding direction (right-hand or left-hand) is not specified.

It is worth noting that in practice, the white wire is not always plus and the black is not always minus. It is equally possible that the opposite is the case. Similarly, the generalization that shielded cables are always inner = plus / outer = minus cannot be taken for granted. In practice, the designation of plus and minus is quite arbitrary. Each manufacturer decides for themselves and rarely defines which is plus and which is minus, therefore it is strongly advisable to test the connections accordingly.

Whereby two pickups are switched in parallel, both minus poles and both plus poles respectively must be connected with each other in order for them to operate correctly. In the event that the pickups are in series, such as in a Humbucker, the minus pole of one coil is connected to the plus pole of the other coil. This causes the signal voltage to be added together. If an opposite phase combination is desired, the plus pole must be connected to the minus pole of two coils in parallel operation. The opposite is the case if they are to be switched in series, i.e. either both plus poles are connected together or both minus poles. The best so-called out-of-phase sounds are obtained when both coils which work against each other are positioned as far apart as possible. On a Stratocaster, for example, these would be the neck and the bridge pickup. It makes no sense to switch the coils ‘against’ each other within a single Humbucker for example, since they literally cancel each other out and the signal becomes extremely quiet.

6. Buzz-free switching

Many musicians find it annoying when buzz or hum from the amp is audible while they are playing. This occurs with common single coils. They pick up magnetic alternating fields from the vicinity caused by electrical transformers in amps, line-level devices such as effects units and from ambient sources such as fluorescent lamps and overhead wires for trains and trams. The Humbucker was invented in order to solve the problem. It is made of two coils which are combined to cancel out interference from outside sources. To avoid the string sounds from compensating each other, the magnetic north poles point in the direction of the strings through the one coil, the magnetic south poles point through the other. Usually, both coils are in series. This doubles the signal, i.e. the output voltage is twice as strong as from a single coil. This also occurs with parallel switching, which is possible on guitars that are fitted with more than one single coil. The nearest single coil or ‘immediate neighbor’ is given ‘reverse wound, reverse polarity,’ RWRP. On a Stratocaster, at least in the second and fourth switch position, the resultant sound of the instrument is buzz-free. As a rule, an even number of coils must be switched on at a given time with an equal number of north and south pole coils. It is irrelevant whether they are parallel or in series. In any event, they must be switched as outlined above.

Using a Megaswitch is somewhat more complicated. Here, for example, one coil of a Humbuckers on the bridge is switched in parallel with a single coil in middle position. If buzz-free operation is desired, then these must be north pole and south pole. Furthermore, plus must be connected to plus and minus to minus. Here, it is important to establish which magnetic polarity a single coil has before assigning the switch positions so that when the Humbucker is split, the coil which has the opposite magnetic polarity operates at the same time.

How can you establish the polarity of a single magnet? Tie it on one end of a piece of thread and let it dangle in the air at least a half a meter away from a large metal object. Initially it moves, but after a short period it comes to rest in a given position. The end which points to the north is the north pole; the other end is the south pole. (In the vicinity of the earth’s geographic north lies the magnetic south pole!) This also works with single coil pickups which have single magnets or with a single bar magnet under the coil. It doesn’t work with Humbuckers or with single coil pickups that have two magnets under the coil, such as the P90 or the P94. To establish the polarity of such devices, take a single magnet or a single coil the polarity of which is known to you and test how it attracts and repels the pickups you wish to test. A minimum of 1 cm distance from the pickup must be maintained. The physical law whereby the same poles repel each other and opposites attract is demonstrated when (1) the distance between both magnets is big enough and (2) both magnets are of similar strength. Magnets which differ greatly in strength always attract each other over short distances because the stronger one reverses the polarity of the weaker one. It is important to avoid being misled by this.

When a buzz-free out-of-phase sound is desired, two coils with the same magnetic polarity must be switched opposite to one another to achieve it.

A completely buzz-free result can only be obtained if both coils have the same number of winds. A typical Humbucker which has been manufactured with care usually has identical coils. This is not the case, however, when two different Humbuckers are switched to single coil position, i.e. are split and the remaining coils are used together. The same applies to a split humbucker and a single coil. The number of winds on the coils often differs, which causes incomplete compensation and therefore, residual hum. Although it is not ideal, it is considerably quieter than the hum generated by a single coil by itself.

With four-wire Humbuckers, the question often arises, which wire goes on which coil? The answer depends on the brand. A black wire can correspond to a red, green or white one, for example, which means it is important to consult the instructions. If the instructions are not available, this can be established quite simply using an Ohmmeter. The typical resistance of a coil is approximately a few Kilo-ohms. Which pair of wires belongs to the coil with the adjustable screws and which ones belong to the one with the fixed poles? This information is rarely included in the instructions. You can test it yourself by soldering a jack socket and connect the coil with a guitar cable with an amp that is switched on. You touch the poles in turn gently with a small metal device such as a screwdriver. The pole which makes a loud cracking noise is the one to which the wires should be connected.

The colored wires in the switch positions shown here are those which were used by Schaller pickups. They are designated as follows:

• White and green: North pole coil
• Yellow and brown: SüSouth pole coil
• Light colors (white and yellow): Plus according to the aforementioned definition
• Dark colors (green and brown): Minus

These colors must then be altered according to the individual colors of a particular manufacturer.

7. Connection of the wires

The colors of the connecting wires used in the drawings (except "PR") correspond to those of the Schaller pickups (white, brown, green yellow). Other manufacturers usually use other colors; here more or less everyone has his own assignment to the coils, which should be explained in the respective installation instructions. The electrical polarity, however, is practically nowhere specified. For "translation" between the Schaller designations and those of the various manufacturers, the following list can serve, in which the connections and polarities of some common types are mentioned (without claim to completeness). The information is valid for the current production. With very old specimens - especially from the "vintage" time - it can sometimes be different, because at that time one did not pay so much attention to it. This would have to be tested in each individual case.

8. Color codes for wiring

9. About the potentiometer values

It has become common practice to use control knobs with 250 kOhm for single coil pickups and those with 500 kOhm for Humbuckers. This is not a hard and fast rule, however and neither is it always the case in practice. Generally, the following applies: With 500-kOhm volume control knobs, higher frequencies are more accentuated than with 250-kOhm volume control knobs. The difference is not substantial, however. If someone using single coils wants a brighter sound, they can replace their 250-kOhm volume control knob with a 500 kOhm version. Conversely, the high frequencies of a Humbucker can be reduced by switching to a 250-kOhm volume control knob. In essence, the choice of volume control knob is a matter of taste and the resultant sound depends largely on the amp. In any event, trial and error, rather than theory is the best policy.

When the volume control knob is turned down to reduce the volume the sound usually loses its brightness. This undesirable ancillary effect can be reduced by installing i.e. soldering a small capacitor between the input (i.e. the right position) and the output (the wiper). Optimum values here are 330 pF, 470 pF or 680 pF. The eventual choice is a matter of taste. These capacitors are not illustrated in the switch diagrams. It is also worth noting that, with passive pickups, the characteristic transfer of sound also depends on the capacity of the guitar cable. This is due to a physical phenomenon and cannot be avoided.

10. Pickup configurations with pin assignment as PDF downloads

SSS: three single coils (bridge, middle and neck)
HSS: one humbucker (bridge), two single coils (middle and neck)
HH: two humbucker (bridge/neck)
HSH: one humbucker (bridge), one single coil (middle) and one bumbucker (neck)
HS: one humbucker (bridge) and one single coil (neck)
SH: one single coil (bridge) and one humbucker (neck)
H: one humbucker (bridge)
SS: two single coils (bridge/neck)
HH4P: two humbucker (bridge/neck) with four potentiometers - Megswitch rotaryHHH4P: three humbucker (bridge, middle and neck) with four potentiometers - Mageswitch rotary

11. Schaller Megaswitch types with circuits as PDF downloads

Megaswitch type E
Megaswitch type E+
Megaswitch type S
Megaswitch type P
Megaswitch type M
Megaswitch type T
Custom template for own Megaswitch type M schematic
Seymour Duncan P-Rail Pickups