Eden Nemesis NA650 User manual

Nemesis
Owners Manual
NA650
Bass Guitar Amplifier
THE LEADER IN BASS AMPLIFICATION.
© 08/10/2005 by U. S. Music Corp.

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Bass Guitar Amplifier
NEMESIS NA-650
OPERATION MANUAL
Publishing Date 08-10-2005
FOREWORD
Congratulations on the purchase of your new Nemesis NA650 Integrated
Amplifier System. All of us at Eden are totally committed to providing you
with the very best bass guitar systems in their class. Our goals are to offer
you the outstanding performance quality of a top-notch, professional bass
amplification system at a reasonable price point, and to make Nemesis
amplifiers the most musical and reliable Bass amplifiers available.
This manual will cover domestic and international versions of the NA650
Integrated Amplifier.
The NA650 delivers 275 watts RMS output @ 8 Ohms, 440 watts @ 4
Ohms and 650 watts @ 2 Ohms, all with +3dB of headroom. This amplifier
also features a thermostatically controlled, active cooling system with built-
in thermal safeties.
You have purchased what we feel is one of the finest bass amplifiers
in its class. The pre-amplifier section, with its familiar Eden Enhance control
and powerful semi-parametric tone control system is coupled to a gentle
auto-compression circuit, allowing you to achieve a wide array of sounds.
This compact, rack mountable package houses modular circuits made with
superior components and designed for years of trouble-free service.
The Nemesis products group is the result of our quest for ultimate bass tone
and maximum reliability. Your amplifier was designed, engineered and
manufactured equivalent to aircraft vibration standards and housed in a
welded steel chassis with steel top to ensure maximum reliability. The
modular design allows quick repair in the field should such a need arise.

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The Nemesis line of amplifiers is the result of our research and development
in combining high performance and compact size. Just as a skilled craftsman
needs good quality tools that won't let him down on the job, so does a good
musician. We hope you enjoy the tool we’ve created for you. Have fun; play
low!
Please read this manual in its entirety before operating your new amplifier.
Failure to do so could result in misuse or damage. We’ve taken the time to
write it, which was a lot longer than the time it will take for you to read it.
Help us help you by taking a few moments to learn how to properly use your
new amp. You’ll be glad you did!
Please complete for your records:
Date of Purchase: __________________________
Model: ___________________________________
Serial Number: _____________________________
Dealer: ___________________________________

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CAUTION!
Your ears are your most important piece of
equipment. Unfortunately, they cannot be replaced
as easily as your other gear. Please take the
following warning seriously.
This product, when used in combination with
loudspeakers and/or additional amplification may
be capable of producing sound levels that could
cause permanent hearing loss. DO NOT operate at
high volume levels or at a level that is
uncomfortable. If you experience any discomfort or
ringing in the ears or suspect hearing loss, you
should consult an audiologist.
Thank you for your purchase of an Eden bass
guitar product. This unit has been designed and
constructed to give you years of trouble-free service.
Please take the time to review this manual
and to send in your warranty registration card.

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FRONT PANEL FEATURES
Input Jack – Designed to accept a standard ¼ inch mono phone plug. For
best results use a high quality shielded cable to connect your instrument to
the amplifier. The input is buffered and will handle standard passive, high
level active, and piezo input signals.
Gain Control – Regulates the first gain stage of the preamplifier and
controls the amount of signal available to the system.
Set Level Indicator – This light helps the user set the appropriate amount of
gain. When set properly, the indicator should light on your loudest/lowest
notes. We’ll go over this in more detail later in the manual.
Compressor Bypass Switch – This switch allows you to bypass the front
end Compressor/Limiter. The Compressor/Limiter in your unit is a fixed
threshold type. You adjust the Compression level by turning the gain control
up or down until you get the amount of compression you want. You may
find the bypass switch useful for getting that maximum punch when you are
slapping or popping hard.
Gain Boost Switch – Depressing this switch engages a +10dB boost. This
feature is useful for basses that have a low signal level. The light is on in the
High gain position.
Edge Control – Allows you to dial in as much or as little vintage tube style
distortion as you like. The control produces a warm single-sided, even order
harmonic distortion that sounds just like the old tube heads. With the control
turned fully counter-clockwise, the circuit is bypassed. The farther to the
right you turn the control the more distortion you will get. The distortion is
fairly subtle at low input levels and is more pronounced at high gain settings.
Enhance Control – Called the “Magic Knob” by some, this complex
control simultaneously boosts the very low bass, upper middle, and high
frequencies while putting a dip in the lower middle frequencies.
It is flat when set to its minimum level (fully counterclockwise).

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Mute to Tune –When this switch is engaged it mutes both the stage sound
and the D.I. send. Only the tuner output stays hot. The Mute is on or muted
when the LED is on.
Semi-Parametric Equalizer –Allows you to dial in a specific frequency to
enhance or cut. This feature is especially useful for upright and acoustic bass
guitars that have a resonant frequency. Because we’ve included a bypass
switch, you can also use it to create a second tone that is available
instantaneously. (You’re welcome.) The frequency is adjustable from 40Hz
to 10KHz. The level can be adjusted +/- 15 dB. The control is FLAT when
the level control is at 12:00 position (straight up).
Three Band Tone Controls – Divides the audio spectrum into three bands:
Bass, Mid, and Treble. The Bass and Treble controls are shelving type
filters. The Mid control is a band pass type filter. These controls give you a
broad general control of the tone shaping.
D.I. Selector – Allows the user to choose to send the D.I. either pre-EQ or
post-EQ.
D.I. Level – Controls the level being sent from the XLR balanced output
jack. We suggest setting the control at approximately 12 o’clock initially. If
the signal to the board is too hot, it’s better to engage the Input Pad on your
channel of the board than to turn it down here, if at all possible. In general,
it’s better (in terms of signal-to-noise ratio and dynamic presentation) to
send as hot a signal as possible to the board. However, you can adjust the
signal level, if necessary, so make sure your soundperson or recording
engineer is aware of this capability.
Master Volume – Controls the main stage sound level and the Head Phone
outputs.
Headphone Jack – Accepts a standard ¼ inch stereo or mono headphone
plug. It can also be used as a Master Output send to slave another amplifier.
DC Indicator – When lit, shows that the low voltage power supplies are
operating.

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Mains On/Off Switch – This switch turns the system power ON or OFF.
The switch illuminates to indicate the presence of AC power present in the
chassis. This switch is prior to the fuse. The light in the switch may flicker
depending on local voltage conditions. This is normal and nothing to be
concerned about.
NOTE: The Mains Switch will illuminate even if the fuse is blown.
However, the DC Indicators will not illuminate if the fuse is blown.
IMPORTANT NOTE: When attached, the included lighted footswitch will
defeat the Front Panel controls for the Mute to Tune and Enhance Bypass
functions.
BACK PANEL FEATURES
Amplifier Power Rating:
RMS output (with +3 dB headroom):
275 Watts @ 8 Ohms
440 Watts @ 4 Ohms
650 Watts @ 2 Ohms
Cooling System – Your amplifier features a thermostatically controlled fan,
which will switch on when the internal temperature reaches 130 degrees F.
In low volume situations (into 8 Ohm loads) the fan may not come on at all.
The cooling system also features a high temperature thermal safety system,
which will activate a circuit if the operating temperature goes above 200
degrees F. This circuit will automatically turn off the output of the system in
the event of overheating. It will automatically reset itself as soon as the unit
cools down to a safe operating temperature.
NOTE: the D.I. will continue to operate normally even when the amplifier is
in thermal safety mode. Only the stage sound will be lost.
IMPORTANT NOTE: Excessive heat is a Very Bad Thing and can
result in severe damage to your amplifier. DO NOT bypass or
disconnect any part of your thermal safety system. Doing so will
immediately void your warranty!

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Combination Power Cord Jack and Fuse Holder – The removable power
cord is attached here. To access the fuse holder, pull the holder out of the top
of the power receptacle. Your unit was shipped with a spare fuse inserted in
the fuse carrier. USE ONLY THE SAME SIZE AND TYPE FOR
REPLACMENT. Using a fuse with a different rating than specified is a
VERY BAD THING and can cause damage to your amplifier. All
models come with a holder marked (FUSE) or (115/230) and are factory
configured for 100/120/ 230/240 only and must be adapted by a service tech
for any voltage change.
Fuse Requirements:
USA @ 120 Volts /60 HZ – 6 Amps, 5 x 20 mm GMC/T/slow blow
Europe @ 240 Volts/50 Hz - 3 Amps, 5 x 20 mm GMC/T/slow blow
Japan @ 100 Volts/60 Hz - 7 Amps, 5 x 20 mm GMC/T/slow blow
IMPORTANT NOTE: Always use slow blow or time delay type fuses.
Do not use fast blow fuses.
To convert your amplifier from US to European fusing, remove the Fuse
Holder and insert a 3 Amp slow blow fuse. Flip the fuse holder over and
reinsert.
IMPORTANT NOTE: In order to operate properly in other parts of the
world, your amplifier may require minor modifications. These
modifications must be made by a QUALIFIED technician. Contact your
local distributor for further information.
Speaker Outputs – These consist of two ¼ inch jacks and two NL-4
connector (sometimes called a Speakon). The jacks are wired in parallel. The
total speaker load impedance should not go below 2 ohms. On NL-4
connectors, we use +1, -1 connections.
Ground Lift Switch – This switch lifts the ground within the balanced
output system to allow you to eliminate excessive noise/ground loops when
connected to external systems.

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Recording Out (D.I.) – This fully balanced XLR output allows you to send
a pre- or post-EQ signal to a recording or sound reinforcement mixing
console. We use Pin 2 hot configuration. Adjusting the Master Volume
control will not affect this send. This output is designed to use with phantom
powered systems. However, it never hurts to turn off the phantom power at
the board, if possible.
Mono Pre-EQ Effects Send/Return – These standard ¼ inch jacks allow
you to send and receive your signal to and from external devices. This
effects loop is positioned post (behind) the compressor and before the
Enhance control and the tone section. This loop is at line level; do not use
instrument level effects in this loop as they tend to be overloaded by the
higher signal level which can cause distortion.
Tuner Out Jack – This standard ¼ inch jack is designed to provide a pre-
gain signal for connection to a tuner. It can also be used to provide pre-tone
signal to other devices such as a direct box or console. The signal is enough
to provide adequate signal to virtually every tuner on the market.
OPERATING INSTRUCTIONS
Mechanical and Thermal Issues – During operation, your amplifier should
always be placed away from sources of moisture or heat. Care should be
taken not to obstruct the ventilation holes on the bottom and sides of the
unit. In the event of thermal shutdown, you should eliminate the cause of the
thermal problem (poor ventilation, speaker loads lower than 2 ohms)
immediately. The supplied rack ears can be used to install your amplifier in
a conventional equipment rack for protection during transportation.
Electrical Connection – The NA650 requires at least 10 Amps of correctly
wired alternating current for proper operation. Providing less than 10 Amps
of power may result in poor amplifier performance, so it’s probably not a
good idea to plug all of your band’s gear into a single wall outlet.

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Connections – All instrument-level input connections (everything but the
speakers) should be made with high quality shielded cables. The use of
speaker cables for input connections will result in excess noise. Speaker
connections should be made with high quality 16 gauge or heavier
unshielded speaker cables. We recommend 10 or 12 gauge cables. The use
of shielded line or instrument cables for speaker connections can
damage your amplifier. The speaker cable should be as short as possible.
INITIAL SET UP
As bassists, each of us has in our head a concept of our perfect sound. Eden
amplifiers are designed to help you easily achieve the sound you hear inside
you. However, it’s a multi-step process as explained below.
In order to ensure the ultimate in tone, it’s important to follow the procedure
outlined below. Don’t skip steps; don’t jump around. Yes, this may take a
minute or two, but the work is well worth it. Once they’ve done it a few
times, most users can do it time and again in about a minute.
IMPORTANT NOTE: Before you plug in your unit for the first time,
please do the following things. First, turn the power switch to the OFF
position. Check the back of your unit for the correct voltage notation for
your county of operation.
Once you’ve ensured correct voltage, set the Master Volume control to
minimum (fully counter-clockwise). Set the tone controls to the center
position (12:00 or 0). Turn the Enhance control to the minimum position. Set
the Input Gain control to the minimum (fully counter-clockwise). Set the
Compressor to the OFF position (push the switch IN). This will set your
amplifier up flat and with the Compressor disengaged. Next, plug in the
power cord to the AC inlet on the back of the unit. Use only a safe grounded
receptacle for proper operation at the correct voltage for your country.
Double check to make certain your amplifier is set for the correct voltage in
your country. Double check that all connections and switches are correct for
your chosen mode of operation.

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Turn On – Once you’ve completed the steps above, you can plug in your
bass and turn on the unit (plug it in first, ok?) and let’s get started. We
recommend turning your system on with the Master Volume control set to
its minimum position. This will prevent any unexpected signal from being
sent to your speakers.
Setting Your Level – Remember, begin with the Input Gain, Enhance,
Compressor and Master Volume completely OFF – fully counter-clockwise.
All EQ should be set flat, that is, at 12:00 – straight up.
While playing your lowest note (or loudest), slowly turn the Input Gain up
until the Set Level light begins to blink with regularity. If you go past 2 or 3
o’clock, you may engage the Gain Switch to better match the gain of your
instrument to the amplifier.
If you have disengaged the Compressor as we suggested, the Set Level light
will barely blink on your loudest notes when you reach clipping in the Input
stage. We recommend you decrease gain one or two clicks to ensure there is
no clipping in the system. By the way, this is David’s favorite way to set
level, even if you intend to use compression.
Once you have properly set your Input Gain, turn the Master Volume up to a
comfortable listening level and proceed with the rest of the setup process.
Setting the Compressor - If you want to use compression, engage it now by
turning the Compressor Defeat switch OFF. The compressor light will now
blink when your gain goes above the compression threshold. This will
generally show up more on the lower notes, or when you employ Slapping.
(A properly compressed Slap sound is very cool, indeed.) If you want more
compression, increase the Input Gain a little at a time, until you achieve the
amount of compression you desire.

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SETTING YOUR EQ
The frequencies that you’ll need to boost or cut are dependent upon your
instrument, playing style, speaker cabinets, and venue. Extreme settings of
boost or cut are unlikely to be necessary or helpful. We are frequently asked
to provide suggested settings for various styles of play. We have discovered
though, that most of our endorsers tend to set their EQ generally flat, using
varying amounts of the Enhance Control to achieve their sound. In fact, a
number of our recording artists tell us that their standard recording set-up is
to have the Enhance set at approximately 9 or 10 O’clock and the tone
controls set flat.
We encourage you to experiment with different settings to obtain the sound
you desire. We have included some EQ panel diagrams at the back of this
manual to help you record your settings.
Enhance – Once you’ve set your gain, you can move on to setting your EQ,
beginning with the Enhance control, or Magic Knob, as some call it. The
Enhance circuitry adds very low bass, upper mids and highs while scooping
out a bit of low middle. The more Enhance effect you dial in, the greater the
boost (and cut). As with all of our EQ controls, a little goes a long way.
Slowly bring the Enhance control up while playing. If you turn it up close to
12:00 on the dial and still don’t have your sound, stop there. Return the
Enhance to OFF or leave it at no more than 12:00 and work with the EQ
section.
Using the EQ Controls – Before you begin to twiddle knobs, let’s talk
about a few things. Excessive boosting of one or more EQ frequencies may
cause an overload in the EQ section. If this happens, the EQ Clip light will
engage. This is a Very Bad Thing and needs to be corrected immediately.
If EQ clipping occurs, you can either decrease the boost or decrease the
Input Gain. Remember, too, that our EQ controls are active, and are meant to
turn both ways – not just UP! This means that you can enhance a certain
frequency spectrum either by boosting that frequency or by cutting the
adjacent frequencies. This latter method has the advantage of maximizing
potential headroom.

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If possible, step well forward of your rig to get a better idea of how you will
sound in the room. You may be surprised at how different you sound once
you step away from the speakers.
NOTE: Many players rely on the Enhance Control (and perhaps a little
Midrange Massage) to get their sound. This method leaves the Bass and
Treble controls available to dial in to a particularly difficult room. Just
something to keep in mind, ok?
Setting Bass Mid, and Treble – OK, now it’s time to set the EQ, beginning
with the Bass and Treble controls. These controls cover a fairly broad
frequency spectrum and a little goes a long way. Adjust these controls up or
down as needed. We suggest playing a few notes in various areas of the neck
so you can hear what your adjustments have done across the fretboard.
Using the Semi-Parametric EQ Controls – Adjusting the Semi-Parametric
control set allows you to focus in on particular frequencies to achieve your
desired tone. We suggest you spend some time experimenting with these
controls to learn more about how they can affect your sound. Here’s an easy
way to do that:
Begin with the frequency control fully counterclockwise. Turn the Level
control to approximately 9:00. Now, while playing, rotate the frequency
control to the right a little at a time. You should be able to easily hear the
frequencies this first set of controls affects.
Now, cut the Level control to approximately 3:00 and do the same thing.
Here are a couple of tips to help you dial in your desired tone:
For a great fretless tone, dial in a little extra at approximately 550Hz.
For extra grind for Rock and other aggressive music, add a little at 1-1.2KHz
or 2-2.2KHz – or both! Remember, though, that a little goes a long way.
Don’t over boost.
NOTE: Remember that the tone you get when playing alone may not cut
through as well as you’d like when playing with others. You may need to
adjust the tone controls to achieve the same (apparent) tone, especially in the
mids and high end.

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A FEW TECHNICAL THINGS TO REMEMBER
Clipping = Bad – Keep an eye on the EQ Clip light. If it blinks, either
reduce Input Gain or cut back on one or more EQ ranges. As we said earlier,
Clipping in the preamp section is a Very Bad Thing and is to be avoided at
all times. If you find yourself running out of amplifier headroom, cut a little
in the lower frequencies, which require the most power from your amp.
You’ll know this is happening if you see the Limit light flashing. As long as
the light is just blinking, you’re fine. But, if it’s on more than it’s off, you
might want to back off a bit.
Frequency Oddities – Two areas are a frequent source of frustration for
bassists trying to achieve their sound: frequency masking and frequency
enhancement. Frequency masking occurs when other instruments
(particularly cymbals and electric guitars) obscure the important upper
harmonic content of your sound. As a result, you find that the EQ settings
that were so perfect at home lack definition in a live setting. On the other
hand, the stage settings that worked so well sound harsh and/or thin in the
absence of other instruments.
Frequency enhancement results from cabinet placement and room acoustics.
A cabinet placed on the floor will have the lower frequencies boosted by
about 3 dB. Placement against a wall adds another 3 dB. A corner adds 3 dB
more. Consequently you may find a surprising boominess to your sound.
Certain qualities in the room itself can also enhance the lower frequencies,
further contributing to this problem. Frequently this effect is more noticeable
in the audience than it is on stage. Compensating for it may result in a stage
sound that may seem a little thin. However the sound is actually quite full
out in front.
NOTE; Remember, you can’t equalize out major physical room anomalies.
If things sound really weird where you are, try moving you rig a few feet
and see if that helps. This may be particularly helpful on saggy stages that
bounce like a drum head. (The propellerhead term for this is
“diaphragmatic.” So says David. – LB)

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YOU’RE DONE. GO PLAY.
There you have it: a quick and easy process to help you get the perfect tone
from your Nemesis amplifier. As previously mentioned, it make take a few
extra minutes the first few times you go through this, especially if you take
the time to experiment with all the knobs and switches, which we highly
recommend.
We are confident that the time you spend getting to know your new friend is
an important investment, one that will pay off immeasurably in Great Bass
Tone. And, after all, that’s why you bought an Eden, right?
OTHER CONSIDERATIONS
Suggested Speaker Systems – Your speaker system should be chosen to
accommodate the characteristics of your amplifier and your predominant
application. If you will only be using one cabinet, a 4 Ohm model will draw
the most current from your amplifier. If you will generally be using two
cabinets, they should both be 8 Ohm models so their combined impedance
will be 4 ohms. If you are uncertain about your future needs, always go with
the 8 Ohm speaker option so that you can add another speaker later if you
need to. In general, adding more speakers will give you a greater volume
increase than adding a few more watts.
We have designed our amplifiers to operate safely at 2 Ohms only because
everyone else is doing it and some users expect it. However, we much prefer
operating at 8 or 4 Ohms because of the markedly improved quality of tone
and dynamic response. But if you really want to, you can operate your
NA650 at 2 Ohms without worry.
Headphone Jack as a Line Driver – On some occasions (such as high-
volume or outdoor situations) it may be desirable to use the NA650 along
with an additional power amplifier and added cabinets. A standard shielded
instrument cable may be used to connect from the headphone jack of the unit
to an unbalanced input of a standard power amplifier. This will provide a
signal that is post-EQ and after the Master Volume control, allowing the
entire system to be controlled from the NA650. This way, you only have to
adjust one set of knobs. This is a Really Neat Thing, huh?

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Using the NA650 Without Speakers -This amplifier is designed to be used
safely with headphones only, without the loud speaker plugged in. No harm
will result from using the amplifier in this fashion. This allows the use of the
unit for practice with headphones and as a preamplifier with other
amplifiers. Neighbors and room mates really love this, which qualifies it as
another Really Neat Thing.
MAINTENANCE
Your Nemesis amplifier has been designed to require minimal routine
maintenance. Attention to the following areas will ensure optimum
performance of your amplifier. We’re serious. Don’t blow this off, OK?
Contact Point Cleaning – One of the weakest links in most bass
amplification systems are the solderless connection points where
instruments, speaker cabinets, effects, and other devices are connected to the
amplifier. (The most vulnerable of these types of connection is the jack on
your instrument). In addition to contamination from airborne pollutants,
these points are frequently assaulted by connectors that have picked up
debris from dirty stages, cases, etc.
This contamination can result in poor contact as well as poor tone, and we
all know that bad tone is a Very Bad Thing. These points should be cleaned
regularly with a cotton swab soaked in denatured alcohol or a commercially
available de-oxidant. Frequent cleaning of the plugs on your cords is also
recommended.
Dust Removal – You should periodically inspect the ventilation openings
on the top and sides of the unit to ensure that they have not become blocked
by accumulated dust. Vacuum the openings to remove any dust buildup.
Dust bunnies are definitely not cool.
The Magic Smoke – Few people realize just how much magic goes into
creating Great Bass Tone. It isn’t something you normally need worry about.
Just have fun and leave all that to us. However – and this is very important –
if you ever release the Magic Smoke from your amplifier this is indeed a
Very Bad Thing, perhaps the worst thing you can do. If you see any smoke
(Magic or otherwise) coming out of your amplifier, immediately turn it off
and seek the services of a qualified magician…uhm, we mean…technician.
DO NOT continue to use the amplifier in this condition.

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Learn More – If you’d like to learn more about your amplifier (or about our
company and its activities), we invite you to visit our website – www.eden-
electronics.com. There you’ll find articles to help you better understand our
products and the technical stuff some people find so interesting. You’ll also
find our FAQ (Frequently Asked Questions) file, which is updated regularly.
While you’re there, check out our on-line forum. There you can meet
hundreds of other Edenites who’ll be glad to help you with any questions
you may have about our gear. Not to brag too much, but we think our forum
is a Really Neat Thing, filled with Really Neat People. We’re pretty sure
you’ll think so, too.
Service – In the event of amplifier malfunction, or questions about your
unit’s operating features that aren’t answered in this manual or on our
website, you should contact your Dealer. Once you and your dealer have
determined it’s definitely a malfunction (and not an operator error) you must
call our Customer Service Department and obtain a Return Merchandise
Authorization (RMA). We WILL NOT accept any gear sent without an
RMA, so save the time and money by calling first, ok?

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Please call the USM Customer Service Dept. at:
1-800-USSOUND (1-800-877-6863)
When you hear the voice prompt, Press 1 on your phone’s keypad.
Please ship Authorized Returns for service to:
Eden Electronics
P.O. Box 338
115 2nd Street
Montrose, Minnesota 55363
Email Website
[email protected] http://www.eden-electronics.com
Eden Electronics
C/O U.S. Music Corp.
444 E. Courtland Rd.
Mundelein, IL 60060
[phone]
[phone](fax)
Eden Never Compromise™
Note for those who care: This manual was written by David (Eden) Nordschow, Eden’s Chief
Propellerhead & Master of All Things Technical, and Lane Baldwin, Eden’s Special Projects Coordinator
(Many Other Functions). Any grammar errors are David and Lane’s fault, as are the attempts at humor.
Please don’t blame anyone else for any weirdness, as we were warned several times. Really.