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Instructions

EM Drive Sustain System

 

Congratulations on your purchase of an EM Drive Sustain System.  This system allows you create infinite sustain on one or more strings of a steel guitar and is designed to become an extension of volume pedal and how it is used on steel guitar.

 

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 – distortion pedals and/or envelope filters – EM Drive power unit - delay and/or reverb pedals – amplifier .

 

Distortion pedals must be placed before the EM Drive unit or oscillation or other undesirable operation will occur.  This is due to the positive feedback used in the EM Drive, which will interact with the high gain used in distortion pedals and cause unstable operation.

 

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 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 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.  The drive coil is 3/8 inch thick and the additional thickness of the tape or Velcro must be accounted for in the spacing.  When ordering the unit, Steeltronics will consult with the purchaser and provide one set of Velcro 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 Drive Coil.  You can think of it as the repulsion creates a wall between the steel pickup and the Drive Coil 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

 

 

Using The EM Drive

 

 

-After ensuring correct magnetic polarity and mounting the drive coil as described above, use the supplied 1/8 inch 3.5 mm jack mono cable to connect the Drive Coil to the Power Unit.

 

Next connect the EM Drive Power Unit into your signal chain by using the ¼ inch Input and Thru jacks.  If connected to a dry output from a delay or reverb pedal the Thru jack is not used.

 

-Connect the DC Power Supply cable to the EM Drive Power Unit, and at this point toggle the bypass switch to ensure the status LED turns on to verify the unit is powered up.

 

-With the status LED lit, turn the gain knob to midpoint of its range (12 o clock) and try playing some notes.  The sustain effect will work in one position of phase switch only, so you will try both positions to find which position works with your setup.  The unit will always be set to this position as you continue to use the device.

 

With the EM Drive active, the volume pedal is modulating the audio volume as before, but it now also is modulating the energy fed back into the strings.  The Gain knob on the EM Drive Power Unit functions as a master volume for the energy fed back to the strings via the Drive Coil, so you will have to experiment to find the Gain setting that works smoothly with the manner you use the volume pedal.  When set correctly, the EM Drive will smoothly fade in energy as you move the volume pedal to sustain a note and the additional energy keeps the string vibrating until it is muted.  Once the EM Drive takes over controlling the string, often you will find the volume pedal will need to be backed off slightly to hold the note at a steady volume.  If you continue adding more volume pedal as the EM drive has taken over control the string will eventually be vibrating with such energy it will rattle against the bar, so the correct Gain setting is critical to ensure a smooth interaction with the volume pedal.  You need a high enough Gain setting that as press down the volume pedal the EM Drive can grab control of string but not so much that the vibration takes off into the string rattling on the bar.

 

There is enough energy available to sustain a note with a clean signal, however you may find the effect more controllable and/or musically useful to use the EM Drive together with an overdrive pedal.  Note that overdrive pedals must be patched in the signal chain before the EM Drive Power Unit as described above for stable operation.