Interstellar
Overdrive
PreampOWNER’S MANUALSWR • CORONA, CA • USA

IMPORTANT SAFETY INSTRUCTIONSCAUTION: TO REDUCE RISK OF ELECTRIC SHOCK, DO NOT REMOVE THE COVER OR BACK. NO USER-SERVICEABLE PARTS INSIDE. PLEASE REFER TO A QUALIFIED SERVICE TECHNICIAN.
A. Read Instructions: All safety and operation instructions should be read before the product is operated.
B. Retain Instructions: The safety and operating instructions should be retained for future reference.
C. Heed Warnings: All of the warnings on this product and in the operating instructions should be adhered to.
D. Follow Instructions: All operating and use instructions should be followed.
E. Cleaning: Unplug this product from the wall outlet before cleaning. Do not use liquid cleaners or aerosol cleaners. Use a slightly damp cloth for cleaning.
F. Water and Moisture: Do not use this product near water; for example, near a swimming pool, wet basement, and the like.
G. Accessories: Do not place this product on an unstable cart, stand, tripod, bracket or table. The product may fall, causing serious injury to a child or adult,
and serious damage to the product.
H. Ventilation: Slots and openings in the unit are provided for ventilation and to ensure reliable operation of the product, to protect it from overheating, thus
these openings must not be blocked or covered. This product should not be placed in a built-in installation such as a bookcase or rack unless proper ventilation isprovided or the manufacturer's instructions have been adhered to.
I. Grounding: This product is equipped with a three-wire grounding-type plug, a plug having a third (grounding) pin. This plug will only fit into a grounding-type
power outlet. This is a safety feature. If you are unable to insert the plug into the outlet, contact your electrician to replace your obsolete outlet. Do not defeat thesafety purpose of the grounding-type plug.
J. Power Cord Protection: Power supply cords should be routed so that they are not likely to be walked on or pinched by items placed upon them, paying
particular attention to cords at plugs and the point where they exit the product.
K. Lightning: For added protection of this product during a lightning storm or when it is left unattended and unused for long periods of time, unplug it from thewall outlet. This will prevent damage to the product due to lightning and power-line surges.
L. Overloading: Do not overload wall outlets or extension cords as this can result in a risk of fire or electric shock.
M. Object and Liquid Entry: Never push objects of any kind into this product through the openings as they may touch dangerous voltage points or shortout parts that could result in a fire or electric shock. Never spill liquid of any kind on the product.
N. Servicing: Do not attempt to service this product yourself as opening or removing covers may expose you to dangerous voltage or other hazards. Refer all
servicing to qualified service personnel.
O. Damage Requiring Service: Unplug this product from the wall outlet and refer servicing to qualified service personnel under the following conditions:
1) When the power supply cord has been damaged2) If liquid has been spilled or objects have fallen into the product3) If the product has been exposed to rain, water, or other conductive liquids4) If the product does not operate normally by following the operating instructions
5) If the product has been dropped or damaged in any way6) When the product exhibits a distinct change in performance.
P. Replacement Parts: When replacement parts are required, be sure the service technician has used replacement parts specified by the manufacturer orhave the same characteristics as the original part. Unauthorized substitutions may result in fire, electric shock, or other hazards.
Q. Safety Check: Upon completion of any service or repairs to this product, ask the service technician to perform safety checks to determine that the product is in proper operating condition.
R. Heat: The product should be situated away from heat sources such as radiators, heat registers, stoves or other products that produce heat.

2 • INTERSTELLAR OVERDRIVE PREAMPDESCRIPTION
At last - a bass distortion unit that faithfully reproduces low end. Also capable of thick, clean tube sounds. May be
used as a practice amp, preamp or effects unit. The preamp of choice for rock bass legend John Paul Jones.

FRONT PANEL FEATURES
Dual independent input jacks compatible for both active and passive instruments
All tube preamp gain stages
Aural Enhancer control
Active bass, midrange and treble controls
Drive function with external drive pedal ability
Blend control for mixing clean and overdriven signals
Effects loop
Tuner send
Rack mountable
Rack Handles
Phase Switch
Standby Switch
On/Off Switch

REAR PANEL FEATURES
Balanced XLR record out with ground lift, pad and mute function
Unbalanced line out (pre master)
Balanced direct XLR out with pad
Speaker jack (4 watts)
Tuner send
INTERNAL FEATURES(1) 12AX7 Preamp Tube
(2) EL84
DIMENSIONS
1.75" H x 19"W x 8.75" D (one rack space)
WEIGHT
10 lbsACCESSORIESInterstellar Overdrive Volume Pedal
Specifically designed for use with the Interstellar Overdrive, thisexternal volume pedal can be used to control the amount of drive
present in the signal path. Great for hands-free switching between
clean and dirty tones.

INTERSTELLAR OVERDRIVE PREAMP • 3

GENERAL INFORMATION AND HISTORY
Around the beginning of 1991 SWR started hearing from an increasing number of bassplayers trying to integrate
some amount of overdrive into their sound. Simultaneously, we were getting more requests for an all tube bass
amplifier. Finally at the January, 1993 NAMM Show in Anaheim, Jack Casady (BASS PLAYER, Sept/Oct '93) and
Hutch Hutchinson (BASS PLAYER, Dec '93) cornered us and said it was time to actively start working on a product toaddress these needs. Since we had become known for designing the cleanest and most hi-fi bass amps possible forthe last 9 years, it would certainly be a challenge.
Most of what was available on the market for overdrive was designed for guitar players. Since the frequency
response was tailored for guitar and not bass in these units, the low end response, as far as the bass guitar wasconcerned, was sacrificed. Secondly, the effect was uneven over the range of the neck. Some notes were overdriven
hard while others were barely distorted. To solve this problem, at least in the studio, bassplayers were sending aclean signal to one channel while sending the distorted sound to another channel and then mixing them together.
This brought back some of the integrity of the instrument but was hard to duplicate "live." After numerous interviews
with our advisory staff, which includes players from metal to jazz, we decided to put the two above requests into one
unit by miniaturizing a tube preamp/power amp, complete with an output transformer for its saturation qualities, intoa single rack space preamplifier/effects system.
Vintage tube amps, known for their overdriven qualities, such as a Versatone, etc., were brought in as a reference
point for dirty. We listened to a MacIntosh for warmth and clarity. We tried class A type power amps and push-pull.
Push-pull was decided upon as it seemed more musical and even. Our R&D expenses skyrocketed as we went
through 8 prototype output transformers. The company that makes our transformers groaned when we told them weneeded to fit it in a single rack space.
After the basic clean and overdrive sounds were achieved our advisory board told us they wanted a built-in direct box,
tone controls, the ability to adjust drive with a foot pedal, blend the clean and dirty signals together as in the studio,
be able to kick in or out the dirty signal with a footswitch and, oh yeah, it had to be really quiet! We said (gulp) no
problem.
Now came the hardest part. What do we name it!? Since the features were defined to us by professional musicians,or "communication between the stars", this can loosely be defined as "Interstellar". Thus, the Interstellar Overdrive.

USING THE INTERSTELLAR OVERDRIVE AS AN EFFECTS UNIT
Using the effects loop of your amplifier, run a shielded patch cord from the send or "to effects" jack on the amp to
one of the inputs on the Overdrive. Read the owners manual to adjust for volume levels, mixes, etc. The clean signal
will always be present at the output of the Overdrive. The Blend control can be used to adjust volume levels if you
plan to go from clean to dirty. The overdriven signal can be switched on and off in the mix via the footswitch. The
tone section can be disabled by setting the controls to the flat (center click) position OR by taking the signal from the
EFFECTS SEND jack. In doing this, you will be using just the tube preamp/power amp section and blend section of
the Interstellar Overdrive. The tone section and Master volume will NOT be operable, so you will probably need aneffects loop on your amp that has an effects return volume control. On SWR amps, use the Blend control to adjustfor volume differences.

USING THE INTERSTELLAR OVERDRIVE AS A PREAMPLIFIERPlug your instrument into one of the inputs of the I/O and use either the balanced or unbalanced output to send asignal to your power amplifier, just as you would with any other preamplifier.

USING THE INTERSTELLAR OVERDRIVE AS A PRACTICE AMP
Since the Overdrive incorporates an all tube power amp to achieve warmth, clarity and overdrive capabilities, you may
plug a speaker in the "speaker" jack for low volume practicing. The power amp will deliver about 5 watts RMS @ 8
ohms. Although a 4 or 8 ohm speaker can be used, an 8 ohm impedance is recommended. The speaker jack is pretone controls and Master volume. Therefore these controls will not function under these conditions. If so desired, anexternal unit (that is made to go between your instrument and the input of an amp) that has tone controls, can beused.

4 • INTERSTELLAR OVERDRIVE PREAMPTIPS FOR USING THE INTERSTELLAR OVERDRIVE
The SWR Interstellar Overdrive Preamp is a unit designed to provide real distortion for bass without significant lossof low end (as occurs when you plug into something like a standard distortion pedal). It can also give you a very
warm and sweet clean tube preamp sound depending on how the controls are set.
The key thing to remember is that the Interstellar Overdrive is in essence a preamp as opposed to an effects unit. It
can be run in the effects loop of another amp, but it operates best when run as its own preamp into a power amp
and then into its own dedicated cabinet.
Another note to remember is that in order to achieve the warm distortion Stella is capable of delivering, the tweeter
on the speaker cabinet it’s being run into should be turned all the way off (if the cabinet even has one to begin with).
Knowing that, here are some setup tips for different types of sounds and situations:
To run as an “overdriven” sound (as opposed to a wide-open distortion sound):
1. Run a regular 1/4" patch cable from the unbalanced 1/4" out to your power amp of choice (this is the patch for
all of the different sounds to follow).
2. Plug your bass into the passive input jack. Just because you have an active bass doesn’t mean you need to plug
into the active jack. Think of the active jack as a -14db pad on your signal. It’s only necessary in basses with intense
amounts of preamp gain.
3. Set the Bass and Mid EQ controls to taste, but set the treble at 3:00 (as on a clock) or higher.
4. Set the Aural Enhancer at 1:30.
5. Set the “Drive” knob to 2:00.
6. Set the “Blend” knob to 10:00 AM.
7. Adjust the Master Volume to taste.
The tone should now be overdriven, but not excessively distorted. Further backing off on the drive knob leads to evenmellower overdrive, and it becomes more “touch sensitive”--as in the harder you play, the more overdriven the signal
will be. The above settings are particularly useful when employing the “In/Out” Footswitch”, because the clean anddirty sounds are nearly equal in level.
To run as a wide-open distorted preamp (or, in other words, totally crunched out):
1. Follow steps (1) and (2) from above.
2. Set the Bass and Mid EQ to taste, but turn the treble up to maximum (about 5:00).
3. Set the Aural Enhancer at 1:30.
4. Set the “Drive” knob up to maximum.
5. Set the “Blend” control to 11:30 AM.
6. Adjust the Master Volume to taste.
This should be some serious distortion. BE SURE THAT THE TWEETER IN THE SPEAKER CABINET IS OFF when using
these settings.
As mentioned above, the unit can also be run as a warm, fat, clean tube preamp. The tweeter can and should be
used for this setting:
1. Follow steps (1) and (2) as above (use unbalanced 1/4" out to power amp, plug instrument into passive input).
2. Set the Aural Enhancer at 1:30.
3. Set the EQ to taste (there’s no need to boost the treble in this instance).
4. Set the “Drive” knob between 9:30 and 11:30 AM, according to taste. This way the sound of power amp tubes
will be achieved, but not so much that they become heavily overdriven. A slight edge should be present on only thehardest-struck notes.

INTERSTELLAR OVERDRIVE PREAMP • 5

5. Adjust the “Blend” knob to taste--closer to the “direct” side will employ less of the power amp tubes, while closer
to the “line” side will use more of the power amp tubes in the clean signal. The “line” side tends to be warmer andfatter, but it’s a good idea to blend in some of the “direct” side as well.
6. Adjust the Master Volume to taste.
The INTERSTELLAR OVERDRIVE VOLUME PEDAL allows for variable adjustment of the amount of drive present in thesignal. In simpler terms, it hijacks the “Drive” knob and allows you to control it from the ground. It does not affectthe level of the “Blend” control, which should still be set to taste.
The INTERSTELLAR IN/OUT FOOTSWITCH allows you to switch between a preset amount of overdrive and a clean signal. It hijacks the drive knob, but in a different way--when the red light is on, the amount of drive present will be atwhatever level the “drive” knob is set at. When the red light is off, it is as if the “drive” knob has been turned down
to the minimum, leaving only a direct signal. It is important to remember that the blend control is still active no matter what you do with the footswitch. For example, if the “blend” control is set all the way to “line” and the “drive” isset all the way to “min”, the engaged footswitch position (red light on) will give you…nothing, acting as a mute. For
best results using this footswitch, use the presets suggested for the “overdriven” sound on the previous page andadjust from there.

FRONT PANEL FEATURES
DIRECT OUT XLR PAD
Adjusts the volume or level appearing at the XLR connector AND the Tuner Send/Unbalanced Direct 1/4" out jack on
the rear panel. See "Back Panel Features" for more information on how these two outputs can be used.
Being a "Pad" as opposed to a volume control, some signal will be heard through these outputs even with the knob
turned full counter-clockwise. As this control is turned clockwise, the level increases.

PASSIVE AND ACTIVE INPUT JACKSThe Passive input jack has 14 dB more gain than the Active input jack. The terms "passive" and "active" refer to thetype of instrument electronics you are using. An "Active" instrument will employ a battery, a passive instrument's
electronics will not. In most cases the Passive input should be used. If you are using line level devices such as a
keyboard or outboard preamp, or using the Overdrive in an active effects loop, you will probably need to use theActive input.
After reading the entire owners manual, perform the following test:
1. Set up your system as you intend to use it.
2. Plug your instrument into the passive input jack.
3. Set the Blend control to the DIRECT position (full counter-clockwise). The Drive control will not be used in this test,
so it's position will not matter.
4. Adjust the tone controls to your liking.
5. Set the Master volume for a low listening level.
6. Play or strike your loudest note.
If you do not hear any distortion or clipping, USE THE PASSIVE INPUT! If you should hear some distortion, be sure
you have eliminated any other possible causes. These can include a weak or dead battery in your bass, power amp
clipping, faulty speakers, the Blend control not set fully counter clockwise, etc.

DRIVE CONTROL
Adjusts the level or signal being sent to the ALL TUBE preamp/power amp. It does not affect the signal at the Direct
Out or the "clean" signal being mixed at the Blend circuit. Since this is also a pad, a small amount of sound will beheard even with the Drive control set to minimum. Overall volume will be achieved using the Drive control in conjunction with the Master volume. To best familiarize yourself with the 3 basic sounds or drive capabilities of theInterstellar Overdrive, first set the Blend control to the LINE or full clockwise position.

6 • INTERSTELLAR OVERDRIVE PREAMPFrom the minimum position to about 10 o'clock, 'Stella (as we have nicknamed it at SWR) will produce a clean, warm
tone reminiscent of the finest tube amps made in the 50's and 60's. To expand on that sound, SWR has incorporated an output transformer whose frequency response has been extended down to 20 Hz and up to 10 KHz.
For those of you into "purity" in the studio or live, you may want to try plugging a favorite cabinet into the SPEAKER
jack on the back panel and miking it. Since the speaker jack is PRE tone controls and Enhancer, this will eliminate allother processing. Single 12's, 15's or 18's seem to work the best in our findings. Naturally, this can be done regardless of your desired setting of the Drive control and actually will enhance the sound coming from your main speakersystem. See the "Speaker Jack" section of the owners manual for more information.
At the 10 o'clock to about the 2 o'clock position of the Drive control, the power amp will begin to reach maximum
headroom and start to distort or be overdriven. If you like a slight "edge" to the peaks of your notes with a small
amount of compression, this is that area. The best example of this sound we can give you is to listen to Jack
Casady's bass parts on the album "Bless It's Pointed Little Head" by the Jefferson Airplane.
After the 2 o'clock position to full maximum, the power amp will be heavily overdriven and saturation of the output
transformer will occur. Heavy distortion, sustain, HARMONIC feedback and compression may be incorporated into
your sound under these conditions.
In the full drive position, we have found that a light touch, whether you are using fingers or a pick, will help produce amore "musical" tone. In fact, you may want to start practicing "Dueling Tubas."

EXTERNAL VOLUME PEDAL
An external volume pedal is available from SWR as an accessory item to the Interstellar Overdrive. The pedal allows
the user to adjust the amount of drive with their foot from a remote location. The benefits of this feature should be
obvious. Plugging in the volume pedal overrides and disconnects the Drive control on the front panel. A myriad ofeffects and dynamics can be achieved using the external pedal.
Great care was taken in the design of this feature so that it does not add hum, noise or frequency loss as inherent
with some common volume pedals. It also allows the patch cable between the unit and the pedal to be ANY length
desired.

FOOTSWITCH IN/OUT JACKWith the insertion of a footswitch, the user is able to defeat the signal in the LINE mode of the Blend control.
Therefore, if you have a preset mix of dirty and clean that you may be using for a solo, or just a change in volume,the footswitch allows you to go from one to the other. Any common footswitch available in your local music store that
performs an "open" and "closed" condition will work. If you do not have a footswitch, you may use a 1/4" phoneplug. Insertion of the plug turns the line function off, taking it out turns it back on.

BLEND CONTROL WITH PHASE FUNCTION
Under the "Input Jack" section of this manual you were asked to perform a test as to what input jack you shoulduse. This action got you acquainted with the clean or "direct" mode of the preamp section. The Drive control section
discussed the "line" mode and it's different capabilities. With the BLEND control you are able to "mix" these two signals both in and out of phase and at varying levels. Two examples follow.

MIXING CLEAN WITH CLEAN
Close scrutiny of the direct sound and the clean sound achieved through use of the Drive control will result in the factthat the direct sound is a little "drier" with more top-end. The Line "clean" sound is warmer and slightly "fatter."
Keeping the Master volume at a listening level, adjust the Drive control until the line signal (blend control full clockwise) is as loud as the direct signal (Blend control full counter-clockwise) by going back and forth with the Blend control. When this is achieved, hit any note and rotate the Blend control from one end to the other. You will notice a risein volume in the mid-position due to the fact that the Blend circuit is adding the two sounds. Keeping the Blend control at 12 o'clock, pull the knob to the "out" position. Your volume level should decrease and the sound will become
quite "thin." By adjusting the Blend control one way or the other, you may get the clean sound you have been searching for all your life. Essentially you are doing the same thing guitar players do when they put their pickups out ofphase. Like going from a Les Paul to a Telecaster. To bassplayers, this would be like going from a Tobias to a
Sadowsky. Of course, different clean sounds can be achieved with the two in phase, but not as radical.

INTERSTELLAR OVERDRIVE PREAMP • 7

MIXING CLEAN WITH DIRTYWith the Blend control in the Line position, adjust the Drive control for the desired amount of overdrive. Now, back off
the Blend control to mix the clean with the overdrive. If the Drive control is at max, the clean or direct sound will nottake affect until about 1 o'clock. As well, you can mix these two sounds both in or out of phase for just about any
desired effect.
If you find a certain mixed setting that you would like to use during solos only, you may preset this as describedabove and kick it in at the proper time via the footswitch function.
It should be noted that the phase switch changes the phase of the DIRECT signal with respect to the line signal. In
other words, the phase switch puts the direct signal out of phase while the line signal remains in phase.

AURAL ENHANCER
The Aural Enhancer was developed to bring out the fundamental low notes of the bass guitar, reduce certain frequencies that help "mask" the fundamentals and enhance the high-end transients. This effect becomes more pronounced
as the control is turned to maximum. The result is a more transparent sound and is especially noticeable using aslap style playing technique.

BASS CONTROL
Cuts or boosts the lower or bass frequencies. Mid position, identified by a "click" is flat (no cut or boost). Starting at
mid position, turning the control counter clockwise cuts the bass response and turning the control clockwise boosts
the low end. The bass control is centered at about 80 Hz.

MIDRANGE CONTROL
Cuts or boost the midrange frequencies and is centered at approximately 200 Hz. Especially useful for "cutting
through" in loud situations.

TREBLE CONTROLThe Treble control is a shelving type tone control that cuts or boosts the high notes and their octaves. Starting frommid position, turning the control counter clockwise cuts the highs while turning the control clockwise boosts the treble region.

MASTER VOLUME
Adjusts the overall volume found at the Line XLR balanced out and 1/4" unbalanced out jack. As the Drive control isincreased or decreased, the Master volume may be used to maintain desired overall volume.

STANDBY SWITCHThe Standby switch should be turned to the ON position after the Power switch is activated. This switch turns on or
off the high voltage to the vacuum tubes, or as the English say, valves. Turning the Standby switch off keeps thetubes in readiness while allowing no sound to pass through the preamp. Turn the standby switch off while changing
instruments or during breaks. When shutting down the entire Interstellar Overdrive, turn the Standby switch off first,
then the Power switch. Reverse this process when turning the unit back on.

POWER SWITCH
Moving the Power switch to the On position activates the electronics as indicated by the blue LED being lit. Don't forget to turn the Standby switch on when you are ready to perform.

*SUPPLEMENTAL NOTE
Because SWR chose to put the least amount of components possible in the signal path to retain purity, turn on andturn off transients appear at all the outputs. For this reason, the Interstellar Overdrive should be turned on first andthe power amp second. Likewise, the power amp should be turned off first and the Overdrive second.

8 • INTERSTELLAR OVERDRIVE PREAMPREAR PANEL FEATURESGROUND LIFT SLIDE SWITCH
When moved to the "lift" position, interrupts or breaks the ground connection to pin 1 of the Balanced D.I. output.
Sliding the switch to the GND position returns pin 1 to ground. If you are experiencing a buzz or hum while using the
D.I. output, try both positions of this switch. If this does not eliminate the problem, check the A/C wiring of the wall
socket with a socket tester as well as associated cables for good connections.

BALANCED D.I. OUTPUT
The Balanced D.I. output is essentially a built in direct box. The signal present is taken from the output of the firsttube stage and then electronically balanced. The signal heard will be the same as that plugged into the input jacks.
The level at this output can be adjusted with the Direct Out Pad located on the front panel. No front panel controls
other than the Pad are active (affect the sound) at the D.I. output.
Wiring of the XLR connector is: pin 1= ground, pin 2= +, pin 3= -TO TUNER INPUT/UNBALANCED D.I. OUT
This feature can be used to access a tuner, drive an unbalanced recording input, and act as a splitter for your input
to drive more than one system.
ALWAYS REMEMBER THAT THE DIRECT OUT PAD CONTROLS THE LEVEL AT THIS JACK AS WELL AS THE BALANCED
D.I. OUTPUT.
THROUGH THE USE OF A "Y" CORD, MORE THAN ONE OF THESE USES CAN BE UTILIZED AT THE SAME TIME.

TUNER
Run a shielded patch cord between this jack and the input to your instrument tuner. This allows the user to tune up
without having to go back and forth from amp to tuner. This feature is on a "side chain" and avoids loading down of
the instrument that could cause a loss in dynamic range.

UNBALANCED RECORDING
Run a shielded patch cord from this jack to the unbalanced input of any recording device. You may also send an
unbalanced feed to a house mixing console.

USE AS A SIGNAL SPLITTER
Since this signal is a direct feed from the input jack(s), you may send an "uncolored" signal to another device. For
example, if you would like to use the Interstellar Overdrive on certain songs and another preamp or device at othertimes, you can plug your instrument into the 'Stella then run a patch cord from this output to the input of the otherpreamp or amplifier. By using a mixer or either preamps Master volumes, you may switch between the two or blend
them together without loading down your instrument.

TUBE ACCESS COVER PANEL
To service the tubes in your preamp, detach the A/C cord and remove the four screws located in each corner of theservice panel. Make sure the tubes have sufficiently cooled. Tube designation from left to right is: EL84, EL84,
12AX7. This is also noted on the panel. The tubes will need replacing if they become noisy, microphonic (sounds likeglass tingling in the background) or dead. Before replacing any tubes, try using a high quality contact cleaner sprayon the tube sockets.
Your unit is installed with premium tubes. Optimum results will be achieved with matched EL84's rated 4, 5, or 6.
Replacement tubes are available from SWR.
The access panel allows servicing of your tubes without having to remove your unit from a rack or removing the top
panel. Access to the 12AX7 is easiest if the middle EL84 is removed first.

INTERSTELLAR OVERDRIVE PREAMP • 9

BALANCED LINE OUT AND GROUND LIFT
Use this output to send a feed to the balanced input of a power amplifier, recording console, house mixer, etc. The
signal present is the output of the Interstellar Overdrive and it's level is controlled by the Master volume on the front
panel. Having both a line and direct balanced out enables the user to send a "clean direct" and colored "line out"
feed for recording or house mixes. The engineer is then able to use each feed accordingly. Some very interesting
mixes can be obtained by panning and mixing the two signals together.
The ground lift switch to the right of this output connects (GND) or disconnects (LIFT) the ground connection to pin 1of the XLR jack. Always be aware of the position of this switch when using the Balanced Line Out. The ground liftswitch does NOT affect the Unbalanced Line Out.
Pin out of the XLR connector: Pin 1= Ground, Pin 2= +, Pin 3= *If the equipment your are plugging into comes from Europe, check the pinouts of the XLR connector for compatibility.
NOTE: The Balanced Line out has a potential of +24dB and should be sent to the "Line In" on mixing consoles, etc.

UNBALANCED LINE OUT
Use this 1/4" jack to send an unbalanced signal to the input of a power amp, mixer, etc. using a high quality shielded cable. The level or amplitude appearing at this output is controlled by the Master volume.

EFFECTS LOOP
The effects loop in the Interstellar Overdrive is an "in line" type. This means that any device inserted in the loop will
always be active. For example, if it should fail, no sound will be heard from the line outputs of the Overdrive.
The Effects Loop is located in the signal chain after the gain stages and Blend control and before the tone controls
and Master volume.
The signal at the effects loop is line level. Units made to go between your instrument and the preamp input may beoverloaded or have signal loss. If your effect has a switch for setting input levels it should be set for 0db or +4db.

SEND JACK
Run a shielded patch cord from the SEND jack to the INPUT of your effects unit. This jack may be used as an additional line level output (pre EQ).

RECEIVE JACK
Run a shielded cable from the RECEIVE jack to the OUTPUT jack of your effects unit.

SPEAKER JACK
Inside the Interstellar Overdrive is a complete miniaturized TUBE power amplifier and output transformer that will
deliver about 5 watts RMS into a 4 or 8 ohm load. With nothing inserted into the speaker jack the power amp isloaded with an 8 ohm resistor. Generally speaking, the resistor portrays a full range, uncolored signal. Speakers andtheir respective cabinets however have natural roll off characteristics, peaks and valleys and changing impedances
based on frequency. The output transformer reacts to these changes. Therefore a speaker cabinet plugged into the
speaker jack will color the sound depending on its natural characteristics.
To experiment with this feature, set up your system as you normally would and listen to the sound. Now insert an
extra speaker cabinet into the speaker jack. Depending on the qualities of the speaker and cabinet, certain nuances
should be introduced into the sound coming from your main speaker system. Depending on the volume of your main
system, you may or may not hear the sound coming from the extra cabinet since it is only producing a few watts.
An excellent alternative to the above is to use a high quality speaker emulator such as those made by Marshall andGroove Tubes. These units offer a variety of speaker types all in one rack space package. These units should be set
to an 8 ohm impedance.
The Interstellar Overdrive may be used as a small practice amp by plugging in a cabinet in the speaker jack.
Remember however that the speaker jack is pre-EQ and Master volume so these controls will not function underthese conditions.
10 • INTERSTELLAR OVERDRIVE PREAMP

A/C LINE/MAINS FUSE
The line fuse can open (blow) due to power surges or high powerline transients. This fuse will also open in the eventof an electronic component failure inside your amplifier.
Correct size and rating of the Line fuse is 3AG, 1/2 amp slo blo.
DO NOT DEFEAT THE PURPOSE OF THIS FEATURE BY USING A FUSE WITH A HIGHER RATING. IT CAN CAUSE FURTHERDAMAGE TO YOUR PREAMP AND VOID YOUR WARRANTY.

A/C LINE CORD RECEPTACLE
Accepts a standard A/C power cable (supplied with the unit in the United States) used with almost all current musical, professional and household appliances. We recommend taking great care when packing up. Put the cable in yourinstrument case, accessory case, etc. If it does become misplaced, replacement will be easy at almost any appliance store, super market or the like.
Electrical rating for a replacement cord should be type SJT or SVT, 3 conductor, 10 amp, 120V. Always purchase a UL
approved product. Outside the United States, contact your local dealer/distributor for proper replacement information.

RACK MOUNTING INSTRUCTIONS & PRECAUTIONS
Several heat producing components are inside the Interstellar Overdrive. These include the 3 tubes, power transformer and load resistor for the power amplifier. Adequate ventilation is achieved by three vents. These are locatedon the top and bottom panels and one at the rear. It is very important that these vents not be obstructed in any way
to avoid overheating.
DON'T FORGET ABOUT IT! A lot of repairs to rack mount equipment is due to loose mechanical connections.
Periodically, take the unit out of the rack and tighten all EXTERNAL screws, dust it off, clean the contacts on yourpatch cords and replace. Make sure the rack rails are in good working order while the rack is empty. You will behappy you did.

EXTERNAL DRIVE PEDAL INSTRUCTIONSThe external drive pedal (available separately from SWR) overrides the Drive control on the front panel and allows theuser hands free operation in adjusting the volume or distortion present in the signal.
To operate the Drive Pedal, run a stereo cord from the 1/4" phone jack provided on the side on the pedal to the
input labeled "External Vol Pedal" on the front panel of the Interstellar Overdrive. This will automatically activate theDrive Pedal and render the Drive knob on the front panel inoperative.
Since the Drive pedal is electronic, any length stereo cable up to 50 feet can be used. As well, the cable need not beshielded. Ready made cables of various lengths can generally be purchased through any hi-fi or electronics store. If
you would like to make your own custom length, use any 3 conductor cable between 24 and 18 gauge (22 is the easiest to find and solder) and two high quality connections between tip, ring and sleeve.

INTERSTELLAR OVERDRIVE PREAMP • 11

INTERSTELLAR OVERDRIVE LIMITED WARRANTY
The INTERSTELLAR OVERDRIVE from SWR is warranted to the original consumer purchaser for
TWO YEARS from the date of purchase against defects in materials and workmanship, provided
that it is purchased from an Authorized SWR dealer. This warranty applies only to products purchased in the USA or Canada.
This warranty is VOID if the unit has been damaged due to accident, improper handling, installation or operation, shipping damage, abuse or misuse, unauthorized repair or attempted repair, or if
the serial number has been defaced or removed. FMIC reserves the right to make such determination on the basis of inspection by an Authorized FMIC Service Center.
All liability for any incidental or consequential damages for breach of any expressed or implied
warranties is disclaimed and excluded herefrom.
Some states do not allow limitations on how long an implied warranty lasts, or the exclusion orlimitation of incidental or consequential damages, so that the above exclusion may not apply toyou. This warranty gives you specific legal rights and you may also have other rights which varyfrom state to state.

SHOULD YOUR SWR AMPLIFIER REQUIRE SERVICE OR REPAIR, PLEASE USE THE
FOLLOWING PROCEDURE:

1
2

Locate your original receipt showing date of purchase, model and serial number.
Determine the closest Authorized FMIC Service Center to your location. The fastest way to get a complete list of Authorized FMIC Service
Centers is on the web at:
http://www.mrgearhead.com/faq/allservice.html
You can also get this information by calling FMIC Consumer Relations at (480) 596-7195

3

To receive warranty service, return the complete product to an Authorized FMIC Electronics Service Center, with proof of purchase, during
the applicable warranty period. Transportation costs are not included in this Limited Warranty.

4

Defective products that qualify for coverage under this warranty will be repaired or replaced, at FMIC’s discretion, with a like or comparable
product, without charge.

For a complete list of Authorized FMIC
Service Centers, and the latest SWR
news, interviews, and more, check out
our website:

swrsound.com

INTERSTELLAR OVERDRIVE OWNER’S MANUAL • Part # 0066573000 • 12/03
Copyright © 2003 SWR

SWR
8860 E Chaparral Rd, Suite 100
Scottsdale, AZ 85250-2618 USA
PHONE: (480) 596-9690
FAX: (480) 367-5262
EMAIL: custserve@fenderusa.com
WEB: swrsound.com