Pendulum SPS-1 Operating Manual

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SPS-1 Stereo Preamp - Operating
Manual

Introduction

Congratulations! You have purchased the finest preamp system for acoustic
instruments available today. But you already know that, so we won't bore you
with the details. Suffice it to say the sound quality and versatility of the SPS-1
are unmatched, both on stage and in the studio. Since most of you would rather
plunge right in and give it a listen, rather than read a novel, we've taken a
different approach to explain how to use the SPS-1. If you're already
technically savvy, you can head back to the Condensed Operating Instructions
that precede this introduction. It is a capsule description of the main features of
the SPS-1, and describes what all the buttons and knobs and jacks do in their
simplest form. It should get you up and running immediately. If you need more
information, or would like to learn about some of the less obvious things you
can do with the SPS-1, read on.

Pickup Combinations - A Primer

Since we've been in the business of putting together preamp systems for
acoustic instruments longer than anyone else, we've come across most of the
configurations that players would like to use with their instruments. The bottom
line is that nearly everyone wants something different, and needs a different
approach to achieving it. For that reason, we've tried to incorporate as many
features as you're likely to need both now and in the future. Since most players
find that one pickup can't do the entire job, the SPS-1 is designed specifically
for blending a pickup with something else, be it another pickup, an internal
mic, or an external mic. What combination you choose depends a lot on your
playing style - flatpicking or fingerpicking, playing solo instrumental music,
accompanying vocals, or playing with other instruments at high sound pressure
levels. Even whether you play in small clubs or with a concert sound system.
The choices you make also depend on whether you're playing live or in the
studio. Here are a few of the most popular combinations, and why people use
them.

Two External Mics

The faint of heart need not apply! If you're a purist, and you're playing solo
guitar in a studio environment, this is the combination you're most likely to use.
However, it requires a pair of high quality condenser mics, and a great
sounding room. Since the SPS-1 has two studio-quality mic preamps,
parametric EQ and stereo output, it's the ideal preamp for going directly to DAT
or digital multitrack. Perfect for recording you solo record yourself. No one
would think of using this combination live, however, and expect to be heard.
Unless, of course, you're doing a classical concert in a great European hall.

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doing a classical concert in a great European hall.

Pickup + External Mic

This is probably the ideal combination for solo acoustic performance, when
you're looking for a good representation of the sound of your instrument but
want some control over how 'woody' your guitar will sound. In most cases the
pickup will be some sort of string-sensitive device, either a saddle or under the
saddle piezo (that's pee-ay-zo folks, not pee-zo or pie-zo) transducer or a
magnetic soundhole pickup. Some work better than others, some are easier to
install, and some are just awful! The idea here is to use the pickup to provide
the direct 'in-your-face' sound of the vibrating string, and combine it with the
ambient sound of the wood vibration the external mic gives you. By varying the
blend between the direct and ambient sound, you can get a very reasonable
representation of your instrument. You can use more pickup in a very lively
room, and more mic in a dead room. By using a single pickup or two pickup
Preamp Module in one channel of the SPS-1, and an external mic in the other,
you can have complete control over this blend on stage. Many players find that
piezo transducers flatter light fingerstyle playing, but are harsh when the strings
are hit hard. The best magnetic pickups, on the other hand, don't fold up when
played hard, but are too 'round' sounding for players who prefer that 'brash'
piezo sound. The choice is up to you. Check out what your favorite player is
using, and see if it works for you. In addition, most studio recording of acoustic
instruments also relies on using these two sound sources. During mixdown you
can establish the blend of pickup and mic that gets the guitar to cut through the
mix. The downside is that you have to have to stay glued to one position for the
mic to be effective. This doesn't work for everyone. And, you can't use this
setup with high stage levels or in a band situation, since both feedback - and
more important - leakage of other instruments into the mic, will present major
problems. Mic selection and placement will often help solve some of these
problems, but not in all cases, or even in all rooms.

Pickup + Internal Mic

This is currently a hot combination, since it gives you the benefits of an
external mic, and you can move around. There is a price to be paid, however,
since a mic inside a guitar will never sound as good as a mic out in front of
your guitar. It may come pretty close, and in many cases it works very well, but
it's still a compromise. After all, it's is a mic in a box. All that said, it works
quite well in many applications, particularly for solo players or groups where
the stage levels are low. The problems encountered with external mics, namely
feedback and leakage, are also problems here. Feedback problems can usually
be cured by keeping the mic out of the stage monitors, which the SPS-1's
monitor output allows you to do. Leakage, however is another matter. The mic
is in a resonant box with a hole in it, which acts as a 'magnet' for low frequency
sound, particularly drums and bass. You can roll off all the low end on the mic,
but isn't that what you wanted the mic for in the first place?

A word about soundhole covers: You may think that by blocking the sound
hole, you're blocking external sounds from reaching the internal mic. This is
true, but you're also preventing air from moving inside the instrument. If the air

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doesn't move, neither does the diaphragm of the mic. Consequently, the output
of the mic drops dramatically, and sounds pretty dreadful. Venting the cover by
putting a few holes in it sometimes works, but often the results are less than
satisfactory. Sometimes you see a gauze pad over a soundhole, which lets the
guitar 'breathe'. It only attenuates high frequency leakage though, not kick drum
and bass.

Mic placement is another matter. The two most popular positions are at the 2:00
or 5:00 position (neck is 12:00, bridge is 6:00), tucked inside the soundhole
about 1-2", 1" below the top, and aimed out at the strings. At certain positions
inside the instrument there are 'nodes' where the low end boominess is less
severe. Hunt around until you find a position that sounds best without EQ.
Some mics are less boomy to start with, particularly hypercardioid capsules.
Sometimes, pointing the capsule up directly at the top, as close to the top as
possible without touching (sort of a PZM configuration), works well with large­body instruments. A little time searching for the best position will pay off in the
long run.

To sum up: internal mics work well when stage levels are low, the mic is kept
out of the monitors, and you've invested some time in hunting for a sweet spot
inside the guitar.

Two Pickups

If you're playing in a band, and it's loud, you can rule out any type of mic. In
this case, there are a couple of options. You can get a 'woodier' sound by
blending a string-sensitive pickup with a contact piezo transducer mounted to
the top. Although the contact pickup can feed back, the feedback occurs at the
cavity resonance of the instrument, which can easily be notched out with
parametric EQ on the SPS-1. The advantage, of course is that leakage is no
longer a problem. You won't get the sound of the pick or your fingers hitting the
strings, but at high sound levels this isn't a great sacrifice. You will get some
body noise, though - the sound of your shirt sleeve scraping against the top, or
your perspiring forearm peeling off the top. Another alternative is to blend two
string-sensitive pickups. A common combination is a saddle piezo pickup
blended with a magnetic soundhole pickup. Here, you're getting two different
tonal colors which you can blend to your liking. The piezo transducer is great
for that brash, 'in your face' sound, and a biting attack. The magnetic pickup is
ideal for getting harmonics out of your instrument (especially for tapping), and
does very nice things for slide playing. It definitely opens a lot of possibilities.

Setting up the SPS-1

In this section we'll highlight the operation for SPS-1 and describe some of the
many things you can do with it. Refer back to the Condensed Operating
Instructions for the front and rear panel layouts.

Standard Set-up with a Two Pickup Preamp Module

· Start off by plugging the Two Pickup Preamp Module into the XLR input of

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Channel 1. Make sure all the pushbuttons on the front and rear panel are in the
'out' position.

· Plug the Preamp Module into your instrument. Set the Balance control on the
Preamp Module to the left (Pickup or Pickup 1), and the Volume control to 0.

· Plug a set of headphones into the 'phones' jack on the front of the SPS-1.

· Set the Monitor level to 10:00. Set the Input and Master level controls to
12:00. Turn the Pan controls to the center (12:00).

· Plug the SPS-1 into an ac outlet and turn on the power switch on the rear
panel.

· Turn up the Volume control on the preamp module to 2:00. Strum your
instrument. You should now hear the pickup in the headphones, and see the
green LED on Channel 1 flash as you play.

· Set the Balance on the Preamp Module to the right (Mic or Pickup 2).

· Strum your instrument. You should now hear the internal Mic or Pickup 2 in
the headphones, and see the green LED on Channel 1 flash as you play.

· Set the Balance control on the Preamp Module to the center .

· Strum your instrument. You should now hear both pickups blended together in
Channel 1. If one pickup is considerably louder than the other, you can use the
balance control to alter the blend. To set the module up for the optimum blend
at the center position on the balance control, you'll have to reset the gain
adjustment trimpots on the top of the module. Please refer to the condensed
operating instructions for more details.

· Press the Input Mode switch (labeled 1 / 1/2), located next to the XLR input
on channel 1 When in the up position (1), the module output feeds Channel 1
only. That is, both pickups are blended to mono into Channel 1. By pressing
this switch (1/2), the two signals split to individual channels; that is, the Tip
pickup now feeds Channel 1 only, and the Ring pickup feeds Channel 2.

· Adjust the Pan controls for a stereo spread between the two pickups. Set Ch. 1
to 10:00, Ch. 2 to 2:00. You should now hear your guitar in stereo.

· Press the Phase Rev switch for Channel 1, on the rear panel next to the Input
Mode switch.

· Strum your instrument. You should hear a different character to the combined
sound, especially on the low frequencies. Choose the combination which
sounds the best to you.

Set-up for a Pickup and an External Mic

It's easy to blend one or two pickups in Channel 1 with an external mic in
Channel 2. You can use the mic on your instrument, or as a vocal mic blended
with your guitar sound.

· Set the Input level controls for Channel 1 and Channel 2 to 0.

· Plug the Single Pickup or Two Pickup Preamp Module into the XLR input of
Channel 1. Make sure all the pushbuttons on the front and rear panel are in the
'out' position.

· Press the MIC button to use Channel 2 as a mic preamp.

· Plug an external Mic into Channel 2's XLR input connector.

· If you're using a condenser mic with phantom power, press the 48V button for
Channel 2.

· Turn up the Input level control for Channel 2 to set the proper level for the
external mic. If you're using the mic preamp with a vocal mic, it may be

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necessary to adjust the Mic Gain Trim control above the MIC switch.

· Set the input level control for Channel 1 to 12:00.

· If you're using a two pickup module with a single pickup instrument, turn the
balance control to the Pickup or Pickup 1 only. If you want to blend two
pickups or a pickup and internal mic in mono in Channel 1 with an external
mic, set the balance control for the blend you'd like.

· Turn up the Volume control on the single or two pickup module to about 2:00.

· You should now hear a blend of Channel 1 and the external mic. Set the Input
controls on the SPS-1 for the blend of the two channels that you desire. Be sure
to keep the signal level between the limits set by the Sig and Peak LEDs on the
front panel.

· For a stereo blend, adjust the Pan controls of Channel 1 and 2.

· Press the Phase Rev switch for Channel 1, on the rear panel next to the Input
Mode switch.

· You should hear a different character to the combined sound, especially in the
low end. Choose the phase setting which sounds the best to you.

Set-up for Two External Mics

· Set the Input level controls for Channel 1 and Channel 2 to 0.

· Press the MIC buttons on Channel 1 and 2.

· Plug the external Mics into the XLR input connectors on Ch. 1 and 2.

· If you're using condenser mics with phantom power on one or both channels,
press the 48V button for those channels.

· Make sure the Input Mode switch for Ch. 1 is 'out' ( 1).

· Turn up the Input level controls both channels to set the proper level. Be sure
to keep the the signal level between the limits set by the Sig and Peak LEDS on
the front panel.

· For a stereo blend, set the Pan controls of Channel 1 and 2 for the stereo
spread you desire.

Set-up for Two Instruments

The SPS-1 can also be used with two single pickup or two dual pickup
instruments connected simultaneously. Each instrument is connected to its own
input channel, and EQed individually. The two pickups of any one instrument
are blended to mono in each input channel.

· Set the Input level controls for Channel 1 and Channel 2 to 0.

· Plug one Single Pickup or Two Pickup Preamp Module into the XLR input of
Channel 1. Make sure all the pushbuttons for Channel 1 are out.

· Plug another Single Pickup or Two Pickup Preamp Module into the XLR
input of Channel 2. Make sure all the pushbuttons for Channel 2 are out.

· Turn up the Input level controls for both channels to set the proper level. Be
sure to keep the the signal level between the limits set by the Sig and Peak
LEDS on the front panel.

· To run the two instruments in stereo, set the Pan controls for the desired stereo
spread.

Set-up for Instruments with On-Board Active Electronics.

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The SPS-1 can also be used with instruments with active electronics, with or
without the preamp module. When used with the preamp module, set up as
above. For use without the preamp module:

· Set the Input level controls for the Channel inputs to 0.

· Plug the instrument into 1/4" LINE IN for either Channel 1 or 2.

· If present, turn the volume knob up on the instrument, and run the any EQ
controls flat.

· Turn up the Input level controls for that channel to set the proper level. Be
sure to keep the the signal level between the limits set by the Sig and Peak
LEDS on the front panel.

Set-up for Use with a Wireless System.

Although the best sound quality is achieved using a Preamp Module and a
connecting cable, the SPS-1 can also be used with a wireless system:

· Set the Input level controls for the Channel input to 0.

· Plug the wireless receiver into 1/4" LINE IN for either Channel 1 or 2.

· Turn the output knob of the wireless receiver all the way up.

· If your instrument has on-board electronics, connect your instrument directly
to the wireless transmitter pack.

· If not, you'll need some sort of battery-powered buffer preamp to prevent
pickup loading and boost the signal level to the transmitter.

· Turn up the Channel level control to set the proper level. Be sure to keep the
the signal level between the limits set by the Sig and Peak LEDs on the front
panel.

Features of Channels 1 and 2

In this section we'll detail the input, output and control features of the
individual channel inputs.

Rear Panel

Line Input

The LINE IN is an unbalanced 1/4" phone jack input for line level signals such
as a wireless receiver, CD or cassette player, or for use as an outboard EQ
during mixdown in the studio. The line input remains active even when using
the XLR input with a Preamp Module or an external mic.

Channel Insert

The INSERT is a mono effects loop for patching an effects device, compressor
or volume pedal into an individual channel. Use a 1/4" stereo plug wired to two
1/4" mono plugs. The 'tip' is the send (to the effect input), and the 'ring' is the
return (from the effect output).

Channel Output

The OUTPUT is a TRS (tip - ring - sleeve) balanced direct output jack for
sending the channel output directly to a tape machine, mixing board, or monitor
amp. This output is also switched on and off under the control of the foot

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switch. In order to connect this output into a 3 pin XLR-type input, use a 1/4"
stereo to 3 pin XLR adapter. Or you can make your own adapter cable by
wiring the tip to Pin 2, ring to Pin 3, and ground to Pin 1. For unbalanced
operation, use a 1/4" mono phone plug.

Input Mode Switch (1 ,1/2)
This switch is used to split the 'Ring' signal from a dual pickup preamp module
to Channel 2. With the switch 'out', the two signals (e.g. pickup/internal mic or
pickup 1/pickup 2) are blended together into Channel 1. By pressing this
switch, the two signals are separated, and the 'ring' signal (e.g. the internal mic
or pickup 2) is now processed by Channel 2.

Phase Rev

Press this switch to reverse the phase of each channel individually. This allows
you to switch the phase of Channel 1 relative to Channel 2, and vice-versa. In
this way, you can listen to a pickup/mic or pickup1/2 combination in or out of
phase with one another. The two combinations will sound very different, and
one usually sounds a lot better.

Mic Switch/ Mic Gain Trim
When this switch is 'in', the channel input is turned into a mic preamp. Use this
mode only when using an External Mic. Leave this switch 'out' when using a
Preamp Module, or using the Line Input. The Mic Gain Trim (located directly
above the MIC switch) is a screwdriver-adjustable control for optimizing the
gain of the mic preamp. Turn it counter-clockwise for less gain, e.g. when using
a vocal mic. It is set at the factory in the clockwise position, the setting you'll
use for micing an acoustic instrument. Set the gain so the 'Peak' LED flashes
rarely.

+48V (Phantom Power)

Press this switch to supply phantom power to an external condenser mic, when
using Channel 1 or Channel 2 as a mic preamp. This switch is only active when
the MIC switch is 'in' - that is, the channel is used as a mic preamp.

Front Panel

Input Level
The Input control sets the operating level, from off to +20 db of gain (module
and Line input), or off to +50 db of gain (mic preamp). Set the input level so
the signal level stays between the limits set by the Signal and Peak LEDs. The
unity gain setting is 12:00 for the line input.

Peak/Signal LEDs

The green 'Sig' LED indicates that the signal level at the input stage is above

-20 dbu, the lower limit for proper operation. Set the Input level so this LED
stays on most of the time. The red 'Peak' LED indicates that the signal level is
near the upper limit for normal operation, +14 dbu, at one of the following
places in the signal path: Preamp Module output, Input stage, EQ input and
output, or Channel output. Set the Input Level control (and the Mic Gain Trim,
if required) so that this LED flashes only occasionally.EQ

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In/Out Switch

Pressing the EQ button illuminates the red 'on' LED and puts the 3 band
Parametric EQ into the signal path. Otherwise, the EQ is bypassed entirely.

Three Band Parametric EQ

Why have we chosen to use a parametric EQ in the SPS-1? Well, regardless of
where a pickup or mic is positioned (though some locations are much better
than others), certain overtones will be exaggerated at the expense of others.
Only a parametric equalizer has the flexibility that is essential for restoring the
natural harmonic balance of your acoustic guitar.You'll find that the SPS-1's
three band parametric EQ, with its overlapping frequency bands and variable
bandwidth, gives you enough freedom to accurately tailor the equalizer's
response to the unique needs of your instrument/pickup combination. Each of
the three bands (LO, MID, HI) of the EQ has three controls, which from left to
right are:

Frequency: This control sets the center frequency for EQ.
The ranges are: LO: 35 - 880 Hz MID: 180Hz - 4.2KHz HI: 840Hz - 19KHz

Bandwidth: The bandwidth control sets how wide or narrow a range of
frequencies around the center frequency are affected.
The range of adjustment is: LO: 0.1 - 1.0 octave MID, HI: 0.33 - 1.0 octave

Level: The level control sets the amount of boost or cut (± 15 db maximum)
that is applied at the center frequency.

There are two things to note; first, the three frequency bands have considerable
range (about 4 1/2 octaves) and overlap - that is, the MID band can also be used
in the middle range of the LO band, and so on for the other bands. This gives
you added versatility, e.g. if one band is dedicated to removing a objectionable
band of frequencies, another band may be applied to access other frequencies
nearby. Also note that the LO band is capable of a narrower bandwidth (larger
'Q') than the others; this is important for using the LO band to 'notch' out any
objectionable low frequency resonances or feedback, particularly the
instrument's cavity resonance. To put the equalizer into the signal path, press
the 'EQ' pushbutton to the right of the Input control - the red LED above it
indicates the EQ is on. With the level controls centered, the equalizer is inactive
and you guitar should sound no different than with the EQ off. Rotating the
LEVEL control to either side of the center position will boost or cut in the
range selected by the frequency and bandwidth controls. Choosing a wider
bandwidth will encompass more frequencies, causing a more audible effect on
your guitar's sound - more like that observed with with one band of a graphic
equalizer or a tone control with a 'peaking' response. With a narrower
bandwidth, fewer frequencies are affected, so more boost or cut has to be
applied to notice a large difference in your guitar's sound. However, the
narrower bandwidth lets you be more selective about the frequency range you
want to target - giving you an extremely effective way of eliminating
unpleasant resonances without affecting other areas of the frequency spectrum.

We'll have a few more things to say about EQing your instrument below.

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Master and Monitor Outputs

In this section we'll discuss the outputs available on the SPS-1, and which
features you'll be most likely to use.

Master Output Section

Pan: The pan controls determine the left (ccw) and right (cw) position in the

master stereo mix for Channel 1 (top) and Channel 2 (bottom). To obtain a
mono blend of the two channels, set both pan controls to the center position.

Master Level: This control sets the level for the Left and Right balanced
outputs on the rear panel. Set the level for the mixing board, amplifier, or tape
machine you're using. The unity gain setting (+4 dbu) is 2:00.

Phase Rev: When this switch is 'in', the overall phase of the Master Outputs is
reversed. Reversing the phase can be useful for feedback control.

On/Loop LEDs: These two LEDs indicate the status of the mute and effects
foot switches. The 'On' LED (top) indicates that the master, monitor and
channel outputs are active. The 'Loop' LED indicates that the stereo effect loop
in the master output section is active. When the footswitch is not used, the 'On'
LED is always lit, and the 'Loop' LED goes on when an effect device is
plugged into the stereo effects returns.

Master Outputs: The two XLR-type balanced stereo outputs are used for
connecting to a snake, mixing board, tape machine, or other balanced input.
This is the output you'll normally use to feed the 'house' sound system. Pin 2 is
hot. To connect up to an unbalanced input, use an XLR to 1/4" adapter. Or, you
can make your own adapter cable by wiring pin 2 to the 'tip' of a 1/4" phone
plug, and pin 1 to the sleeve.
Gnd Lift By pressing this switch, the ground connection (pin 1) of the XLR
output connectors is lifted from preamp ground. Use this to avoid ground loop
hum when connecting to a balanced input. When using the master outputs with
an unbalanced input, make sure this switch is 'out'.

Monitor Output Section

Monitor Level: This control sets the level for the Left and Right unbalanced

outputs on the rear panel. Set the level for the stage monitor, monitor amplifier,
tape machine or other system you're using. The unity gain setting (+4 dbu) is
2:00. The monitor level also controls the signal level sent to the headphone jack
on the front panel.

Phase Rev : When this switch is 'in', the overall phase of the Monitor Outputs
is reversed. Reversing the phase can be useful for feedback control onstage. Try
it both ways and use the position that works best. The best setting will depend
on the position of your guitar relative to the monitor speakers. So, it may
change from night to night.

Monitor Source Switch (MIX / CH 1): The Monitor outputs are normally fed

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the master stereo mix (MIX), which is identical to the Master outputs. Press
this switch (CH 1) to feed only Channel 1 directly to the monitors. This can be
useful for controlling feedback in pickup/mic applications, by feeding the
pickup-only signal from Channel 1 to the stage monitors. The Channel 1 signal
is mono, post-EQ, post-Insert, but pre-stereo effects loop. It is turned on and off
by the foot switch.

Monitor Outputs: The two 1/4" unbalanced stereo outputs are used for
connecting to a stage monitor, monitor amplifier, tape machine or other
unbalanced input. This is the output you'll normally use to feed your onstage
amp or 'monitor' sound system. The output is assigned to the stereo mix or
channel 1 via the monitor source switch.

Phones: This is a separate low impedance output stage for driving a set of
stereo headphones. The output level is set by the Monitor Level control, and the
feed is controlled by the monitor source switch. The phones output is not
affected by the monitor or master Phase Rev switches. We've given the
headphone amp extra level and drive capability to work with all types of
headphones. The 1/4" stereo jack is wired according the industry-accepted
standard: Tip = left, Ring = right. Stereo Effects Interface The Stereo Effects
interface is used to insert true stereo effects into the stereo mix of the Master
and Monitor Output sections. Rather than just a simple effects loop, the SPS-1's
stereo effects interface allows you to distinguish between effects that you want
to mix with the unprocessed guitar sound (e.g. reverb), or those you want to
replace the unprocessed signal (e.g. compressor or multi-effects processor).

Send Outputs and Return Inputs: Interfacing to the stereo effects mixer easy.
Just connect the L and R inputs from your stereo effects device to the L and R
send output jacks on the rear panel of the SPS-1. These are unbalanced, low
impedance outputs that are capable of driving any effects device. Next, connect
the L and R outputs from your stereo effects device to the L and R return input
jacks. The Return inputs are also unbalanced. The 'Loop' LED on the front
panel will light, indicating the effects returns are active. The effects returns can
also be used as a post-EQ auxiliary input. It's a convenient way to combine a
drum machine, synth, or to play along with your favorite CD or cassette!

Replace Switch: With the switch 'out' (the MIX mode) the stereo effects
returns are blended with the dry, unprocessed signal in the preamp. In other
words, the loop is combined in parallel with the unprocessed sound. Use this
mode for combining reverb with the unprocessed guitar signal. - set the 'mix'
control on the reverb unit to return 'wet' or 'reverb-only' signal to the SPS-1.
This way, the dry signal is not degraded by the effects device.

When the switch is pressed (the REPLACE mode), the unprocessed signal is
turned off and only the signal passing through the effects loop is heard. Use this
mode with a compressor, stereo chorus, delay, or multi-effects processor. The
blend of the 'dry' and 'wet' signals is determined by the effects device.

Foot Switch: The Foot Switch jack is used to turn your instrument on and
activates the stereo effect loop. The 'On' and 'Loop' LEDs on the front panel

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indicate that the 'On' and 'Effects' switched on the Foot Switch are activated.

Tuner: This output is a Channel 1 only signal used to drive an instrument tuner.
Using Channel 1 only, which is usually a pickup signal, gives the tuner greater
accuracy. This output remains active when the instrument is muted, for tuning
quietly.

Equalizing your Acoustic Guitar

Comments: Before you start to equalize your instrument's sound, it's probably

a good idea to:

·Listen carefully to your instrument unamplified.
Try to decide what it is you like about the way it sounds, and target any
potential problem areas you feel might need fixing. This will give you a clearer
sense of what you want the equalization to achieve.

· Try to get the best sound that you can from your pickup or mic before
applying any EQ. This includes (if possible) trying different pickups, mics or
mic placement, to get the most balanced sound possible. Remember, it's best to
use only as much EQ as necessary; when less is needed to fix major problems,
more is available to accent the good points. It's also a good idea to perform the
initial EQing by listening through a pair of high quality headphones or in a
quiet, controlled environment (like your home studio). This is the best way to
judge the effect that various control setting are having on your sound. If you're
planning to use the SPS-1 onstage with a sound reinforcement system, setting
up this way first is important: it will help you distinguish problems with the
sound from your guitar and pickup from deficiencies in the sound system.

Main Problem Areas

Since the requirements of each instrument and pickup system are unique, it's
difficult to pinpoint specific EQ setting that will work for everyone. However,
we have found that most of the problems fall into one of four main categories.
Here are a few hints on how to use each of the the four bands you have
available to handle them:

·Too Much 'Boominess':Tuning the LO band to the instrument's body
resonance (typically in the range of 70-140 HZ) is an extremely effective way
of taming an overpowering low end 'boominess', especially with a mini-mic in
the body of a guitar. To do this, set the bandwidth control fairly narrow (around
3:00) and add 12-15 db of boost. Then, lightly tap a finger on the top of the
guitar behind the bridge while tuning the frequency control in the range given
above (the larger the guitar's body, the lower the resonant frequency). At a
certain point, the tapping will turn into a deep 'thud' as you zero in on the body
resonance. (If you listen closely, you'll actually hear a series of harmonically­related resonances - tune in on the lowest frequency one.) Now, cut about 12
db, play a few chords and adjust the bandwidth and level to your liking, while
using the EQ in/out switch for comparison. Cut the level and adjust the
bandwidth to remove as much of this frequency range as necessary. You should

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be able to find a setting that effectively removes the problem without affecting
the rest of the bottom end. The improvement is usually dramatic.

· Lack of 'Clarity': Often, because of the pickup's response or placement, the
guitar's lower midrange overtones get exaggerated. This causes your guitar to
sound 'muddy' and lack definition. Use the LO or MID band (with a fairly wide
bandwidth) to cut a few db in the 400-1000 Hz frequency range.

· Lack of 'Presence': Using the MID or HI band to add a few db in the 3-6
kHz range will help your guitar stand out. Be careful though, since adding too
much or centering on the wrong frequency can make your guitar sound harsh.
On the other hand, some pickups tend to overemphasize frequencies in this
range so you may need cut back in this region.

· Lack of 'Brilliance': Compared to the hyped-up high end we're used to
hearing on recordings, an acoustic instrument can often sounds too 'mellow' to
the modern ear. A broad boost of the HI band above 10 kHz will give you a
'crisper', 'brighter' tone. Applied in moderation, it can bring life to a dull­sounding instrument. Remember, EQ is largely a matter of personal taste

and the specific needs of your instrument may be quite different from these
general guidelines. Don't be afraid to experiment to find what sounds the best

to you.

Technical Extras

In case you were wondering, here are a few of the reasons why the SPS-1
sounds so good!

· The latest in high speed/low noise circuitry is used throughout.

· All inputs and outputs are electronically balanced: there are no transformers in
the signal path.

· We use audiophile-quality components: metal film resistors, polypropylene
capacitors, conductive plastic potentiometers, and a minimum number of
electrolytic capacitors in the signal path.

· A toroidal power transformer is used for minimum hum.

· Single circuit board construction of the Main Preamp Unit and Preamp
Module are used for high reliability.

· Each unit is handcrafted entirely in the USA.

SPS-1 Specifications

Preamp Modules

Input(Piezo or Magnetic): 10 M, unbalanced
Input(mini-mic):15 k, unbalanced, +9 Vdc power to mic.
Maximum Input Level:+15.5 dbu (4.6 Vrms)
Input Noise: EIN less than -113 dbu, input shorted.
Frequency Response:+0/-1 db, 20 - 20,000 Hz

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Distortion:THD less than 0.01% at 0 dbu
Gain:0 to +30 db, adjustable
Output: Balanced, 3-pin mini-connector

Main Preamp Unit

Inputs: Module/Mic: 3-pin XLR, balanced
Line in: 1/4" phone jack, unbalanced, 10K.
Insert: 1/4" stereo jack, tip=send, ring=return.
Mic Preamp:EIN less than -128 dbu, 50db gain.
Frequency Response: +0/-1 db, 20 - 20,000 Hz
Distortion: THD less than 0.007% at 0 dbu
Output Noise:EQ out, unity gain: less than - 93 dbu; EQ in, set flat: less than ­88 dbu
Maximum Output:+21 dbu, unbalanced, +27 dbu, balanced
Channel Outputs:1/4" phone jack, TRS balanced, 600 ohms.
Master Outputs: XLR, balanced, pin 2 in phase, 600 ohms.
Monitor Outputs:1/4" phone jack, unbalanced, 600 ohms.
Effects Sends: 1/4" phone jack, unbalanced, 600 ohms.
Effect Returns: 1/4" phone jack, unbalanced, 10Kohms.
Tuner Output: 1/4" phone jack, unbalanced, 10Kohms.
Phones: 1/4" stereo phone jack, 100 ohms.
Metering:Signal (green): -20 dbu; Peak(red): +14 dbu
Equalizer: Three band fully parametric, ± 15 db boost/cut
Lo: 35 - 880Hz, 0.1 to 1.0 octave (Q=10 to 1)
Mid: 180Hz - 4.2kHz, 0.3 to 1.0 oct. (Q=3 to 1)
Hi : 0.84 to 19kHz, 0.3 to 1.0 octave (Q=3 to 1)
Phantom Power:+48 Vdc applied to pins 2 and 3
Foot Switch:1/4" TRS phone jack, 10 mA current loop.

Power: 120 VAC, 10 Watts

Dimensions
Preamp Module:1.1" x 2.2" x 1.0", exluding input plug.
Main Preamp Unit:1.75" x 19" x 8" (one standard rack space), 6 lbs.
Foot Switch: 4.3" x 2.3" x 1.2"

Notes: 0 dbu = 0.775 Vrms.
All noise measurements are unweighted, 20 - 20,000 Hz bandwidth.
All specifications are subject to change without notice.

Limited Warranty

Pendulum Audio, Inc. warrants to the first purchaser of a new Pendulum SPS-1
Stereo Preamp System that the unit is free of manufacturing defects in materials
and workmanship for a period of one (1) year from the date of purchase.
Pendulum Audio, Inc.'s sole obligation under this warranty shall be to provide,
without charge, parts and labor necessary to remedy defects, if any, which
appear within one (1) year from the date of purchase. All warranties expressed

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or implied made by Pendulum Audio, Inc., including warranties of
merchantability and fitness, are limited to the period of this warranty. Pendulum
Audio, Inc. is not responsible for indirect, incidental or consequential damages
arising from the use or failure of this product, including injury to persons or
property. This warranty does not cover damage due to: misuse, abuse,
modification, accident or negligence. The warranty does not apply if the unit is
repaired or altered by persons unauthorized by Pendulum Audio, Inc. in such a
manner as to injure, in Pendulum's sole judgment, the performance, stability or
reliability of the unit. The warranty does not apply if the unit is connected,
installed or used otherwise than in accordance with the instructions furnished
by Pendulum Audio, Inc. If the equipment requires warranty repair, return
authorization must be obtained from Pendulum Audio, Inc. prior to shipment.
Equipment should not be shipped to Pendulum Audio, Inc. until return
authorization and the proper shipping address is obtained from us. The
equipment (with all its components parts and connecting cables) must be
suitably packaged, including a note with the owner's name, address, telephone
number and a description of the reason for return. You pay two-way shipping
(we recommend UPS or FedEx), and we suggest you insure your shipment.
This limited warranty is in lieu of all other warranties, expressed or implied,
and no representative or person is authorized to represent or assume for us any
liability in connection with the sale of our products than set forth herein. This
limited warranty gives you specific legal rights, and you may also have other
rights which vary from state to state.

Pendulum Audio, Inc.· P.O. Box 339, Gillette, NJ 07933.· [phone] ·
www.pendulumaudio.com