EM Drive Sustain System
Congratulations on your purchase of a EM Drive Sustain System. This system allows you create infinite sustain on one or strings of a steel guitar and is designed to become an extension of volume pedal.
Introduction
The EM Drive allows you to create infinite sustain from notes that are picked normally. Notes are played exactly as you are used to, there is no change in technique or hand position required.
The EM Drive amplifies the signal coming from the steel bridge pickup and routes this energy back to the strings via a drive coil mounted under the strings. When the EM Drive is set up properly the volume pedal control controls the initial note volume exactly as before, but when you depress the pedal to sustain a note in the manner that steel players normally do, the energy from the EM Drive is faded in and keeps the strings vibrating. For a steel player used to volume pedal use, the effect is seamless and its quite easy to find the point where the note will sustain. Typically you will find that as the drive coil signal is starting to control the string vibration, the volume pedal even can be backed off slightly.
Signal Path
The EM Drive must be placed after the volume pedal for correct operation and to allow the drive signal to be modulated. The recommended signal chain is steel output – volume pedal – EM Drive - distortion pedals and/or envelope filters - power unit - delay and/or reverb pedals – amplifier .
Distortion pedals can be placed before the EM Drive unit, however the unit will behave differently since the signal being looped back is somewhat different (due to the distortion). Also, some distortion pedals invert the phase which would have to be accounted for with the phase switch on the EM Drive power unit.
The EM Drive can be connected using both the input and thru jacks (as any other pedal would be connected), or it will also work correctly with the input only connected to the dry only output of a delay or reverb pedal. This may be advantageous for pedal board space considerations.
Attaching The Drive Coil
IMPORTANT -- Depending on the design of your steel case the drive coil may have to be removed each time the steel is put in the case. If the case supports the steel at the corners by contacting the endplates there will be no problem, however some cases support the steel in the middle of the body, and depending on the length of this support, there could be an interference with the drive coil placement. Check for interference by measurement before attempting to put the steel in the case with the drive coil in place.
The drive coil must be placed on the fretboard between the 19th and 23rd fret to prevent magnetic interference. If the drive coil is too close to the existing bridge pickup, there will be oscillation or squealing and the response will be difficult to control. This is due to the strong magnetic field required to drive the high tension strings of a pedal steel guitar. There is ample energy available to drive the strings even with the drive coil at the 19th fret, and you may prefer this placement for plenty of room to pick the strings without contacting the drive coil. As you move the drive coil toward the 23rd fret less drive signal will be required and you will be able to see more fret lines for playing high on the neck. There is a tradeoff here between room for picking and which fret lines the drive coil is covering up
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Optimal spacing is 3/32 to 1/8 inch clearance between the strings and the drive coil. When ordering the unit, Steeltronics will consult with the purchaser for correct drive coil thickness. One set of Velcro will be provided for mounting, additional or replacement Velcro will also be available.
For the sustain system to work correctly both the magnetic and coil electrical phase must be set correctly. The electrical phase is set with a switch on the drive unit, however the magnetic phase must be set manually by orienting the drive coil magnets to the correct polarity. A round magnet with a polarity marker is provide with the unit to accomplish this. The magnets are visible on the bottom of drive coil and can be removed by using a small screwdriver or similar to lift them away from the drive coil blade. The basic principle is the drive coil and the normal pickup need to be the same, with both being for example North Up. Using the provided magnet, check the polarity of the installed pickup and note which way the test magnet sticks to the installed pickup, then install the drive coil magnets so the test magnet sticks to the drive coil in the same orientation. Both drive coil magnets need to be installed with the same polarity, this can also be checked with the test magnet. Also note that if the installed pickup is a dual coil humbucker, the two rows of poles or blades will have each have a different polarity, and the drive coil needs to match the row that it is closest to. The principle at work here is if the polarity of the drive coil and installed pickup are made the same the magnetic repulsion between the two prevents the magnetic flux from traveling in the strings and upsetting the operation of the sustainer. You can think of it as the repulsion creates a wall between the two coils minimizing interaction. If the polarities are not made the same magnetic flux will flow freely between the coils and the sustainer will not work correctly at either setting of the phase switch on the drive unit.
Connecting The Power Unit
The EM Drive is supplied with a 24 VDC 0.5 Amp Center Positive power supply. This unit is specifically selected for use with the EM Drive to provide low noise and adequate current capability.
DO NOT ATTEMPT TO USE ANY OTHER POWER SUPPLY – this could damage the power supply or the EM Drive. This includes any standard 9 volt power supplies such as the One Spot, Pedal Power, and other similar units