Crate Amplifiers BT-350 User Manual
for the
Owner’s Manual
BT-350
BT-350
Bass Amplifier
Bass Amplifier
THIS EQUIPMENT HAS BEEN DESIGNED AND ENGINEERED TO PROVIDE SAFE AND RELIABLE OPERATION. IN ORDER TO PROLONG THE
LIFE OF THE UNIT AND PREVENT ACCIDENTALDAMAGES OR INJURY, PLEASE FOLLOW THESE PRECAUTIONARY GUIDELINES:
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT OPEN CHASSIS; DO NOT DEFEAT OR REMOVE THE GROUND PIN OF THE
POWER CORD; CONNECT ONLYTO A PROPERLY GROUNDED AC POWER OUTLET.
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.
CAUTION: NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
CAUTION: OUR AMPLIFIERS ARE CAPABLE OF PRODUCING HIGH SOUND PRESSURE LEVELS. CONTINUED EXPOSURE TO HIGH SOUND
PRESSURE LEVELS CAN CAUSE PERMANENT HEARING IMPAIRMENT OR LOSS. USER CAUTION IS ADVISED AND EAR PROTECTION IS RECOMMENDED IF UNIT IS OPERATED AT HIGH VOLUME.THE CHART BELOW SHOWS THE U.S. GOVERNMENT OCCUPATIONAL SAFETY AND
HEALTH ADMINISTRATION (OSHA) REGULATIONS WHICH WERE IN EFFECT AT THE TIME OF THIS PUBLICATION FOR PERMISSIBLE NOISE
EXPOSURE, PER 29CRF1910, TABLE G-16.
ACCORDING TO OSHA, ANYEXPOSURE IN EXCESS OF THOSE LISTED ABOVE COULD RESULTIN SOME HEARING LOSS.
Congratulations!
You are now the proud owner of one of the most advanced bass guitar amplifiers available, the Crate BT-350
ThunderBass amp. This flexible and compact unit combines a tube preamp, 7-band graphic equalizer, chorus, biamp capabilities and 350 watts of power in a rugged and attractive package that can be rack-mounted in only three
spaces. A wide array of front-panel controls along with footswitch options allow you to “tailor” the sound to best
suit your personal needs.
Like all Crate products, your BT-350 ThunderBass amp is Musician Made in the U.S.A., using only the best
components. Extensive testing at many stages in its production, including a final “audition” by a skilled musician,
insures you that your BT-350 ThunderBass amp is the best it can be.
In order to get the best possible performance, please read this manual before you use the amplifier.
And thank you
for choosing .
22
BT-350
BT-350 ThunderBass Amplifier
SOUND LEVEL dBA DURATION PER DAY
SLOW RESPONSE IN HOURS
90 8
92 6
95 4
97 3
100 2
SOUND LEVEL dBA DURATION PER DAY
SLOW RESPONSE IN HOURS
102 1-1/2
105 1
110 1/2
115 1/4 or less
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK,
DO NOT REMOVE COVER.
NO USER-SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
ATTENTION
RISQUE D'ELECTROCUTION
NE PAS OUVRIR
ATTENTION: POUR REDUIRE D'ELECTROCUTION NE PAS
ENLEVER LE COUVERCLE. AUCUNE PIECE INTERNE N'EST REPRABLE
PAR L'UTILISATEUR. POUR TOUTE REPARATION, S'ADRESSER A UN
TECHNICIEN QUALIFIE.
VORSICHT
ELEKTRISCHE SCHLAGGEFAHR
NICHT OFFENEN
VORSICHT: ZUR MINIMIERUNG ELEKTRISCHER SCHLAGGEFAHR NICHT
DEN DECKEL ABENHMEN. INTERNE TEILE KONNEN NICHT VOM
BENUTZER GEWARTET WERDEN. DIE WARTUNG IS QUALIFIZIERTEM
WARTUNGSPERSONAL ZU UBERLASSEN.
"IT IS NECESSARY FOR THE USER TO REFER TO THE INSTRUCTION MANUAL"
"REFERREZ-VOUS AU MANUAL D'UTILISATION"
"UNBEDINGT IN DER BEDIENUNGSANLEITUNG NACHSCHLAGEN"
EXPLANATION OF
GRAPHICAL SYMBOLS:
"DANGEROUS VOLTAGE"
"DANGER HAUTE TENSION"
"GEFAHLICHE SPANNUNG"
=
=
Contents:
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
The Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4, 5
The Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Using the Biamp Capabilities . . . . . . . . . . . . . . . . . . . . . .8, 9
Some Suggested Settings . . . . . . . . . . . . . . . . . . . . . .10, 11
Technical Specifications . . . . . . . . . . . . . . . . . . . .back cover
Introduction:
The Crate BT-350 ThunderBass amp is a high-quality bass guitar amplification system that combines
extremely high power with very desirable features. Each feature and control is discussed in detail in the sections entitled “The Front Panel,” “The Rear Panel” and “Using the Biamp Capabilities.”
Crate offers a heavy-duty three rack space enclosure (Crate model #CR-3) which will house the BT-350
perfectly, providing the extra protection and convenience needed when you take your Crate on the road.
Also available is a five rack space enclosure (Crate model #CR-5) which is ideal for use when the BT-350 is
combined with a second amplifier for biamping.
The BT-350 is equally suited for use in the club, the studio or on the stage. When combined with Crate’s
line of superior bass cabinets, the results are nothing less than phenomenal. (But then, what else would you
expect from Crate?)
Features:
Additional information can be found on the pages indicated.
• Tube Preamp: Adjustable Drive control. Low, Mid and High frequency controls. Low and High Boost
switches. Normal (0dB) and padded (-15dB) input jacks. (page 4)
• Graphic EQ: 7 bands. 40Hz to 10kHz. 12dB cut or boost. Master Level control. Footswitch control-
lable. LED Indicator. (pages 4 and 5)
• Master Level: Peak (overdrive) LED indicator. Switchable Limiter circuit with LED indicator. (page 4)
• Chorus: Adjustable Depth and Rate controls. Variable cut-off (“Spectrum”) control. (page 5)
• Biamp: Adjustable crossover frequency control. Low-to-high balance control. Independent Line Out
level control. Balanced (XLR) and unbalanced (1/4”) outputs. (pages 5 and 6)
• Internal Amplifier: 350 watts into 4 ohms. 1/4” mono speaker output jacks. Extensive heatsinking.
Detachable AC power cord. (page 6)
• Effects Loop: 1/4” Send and Return jacks. Allows use of external signal processors. Return jack
doubles as input for power amp in Biamp mode. (page 6)
• Musician made in the U.S.A.
• Crate’s exclusive 5-year warranty (U.S. only, – see your dealer in other areas for warranty information)
33
BT-350
BT-350 ThunderBass Amplifier
INPUTS:
1. 0dB INPUT: Connect your bass
here using a shielded instrument cable.
The output signal of your bass will run
full-strength into the amplifier, which is
fine for most basses having passive electronics and/or low-output pickups. If
your bass has active on-board electronics and/or active pickups, use the -15dB
input jack (#2) to avoid overloading the
amp’s input stage.
2. -15dB INPUT: Connect your bass
here if it has active on-board electronics
and/or active pickups. The bass’s output
signal will be attenuated by 15dB to keep
it from overloading the amplifier’s input
stage.
NOTE: Even if your bass has passive
electronics, if the Peak LED (#9) flashes
at seemingly low levels when you’re
plugged into the 0dB input, try using the
-15dB jack instead.
TUBE PRE-AMP section:
3. TUBE DRIVE: This serves as the gain
control for the BT-350’s tube preamp
section, which gives you the natural
compression of a tube amplifier. For the
best compression. adjust the Tube Drive
control as you strike your strings (hard).
Watch the Peak LED (#9): when the
LED starts to flash, you’ve reached a
choice setting for the best signal-to-noise
ratio and “tube feel.”
4. LOW BOOST: Switch on the Low
Boost and you’ll feel a large increase in
the very lowest bass notes, especially
noticeable when you hit the low B string
of a five or six-string bass. This is due to
the impressive 8dB of gain added at
20Hz, increasing the deep, “floor-shaking” sounds of your instrument.
5. LOW: Adjust the output level of your
low-bass tones with this control: the center position is “flat” (no boost or cut).
Turning the control to the left reduces the
low frequency output; turning to the
right increases the low frequency output.
The Low control primarily affects the
notes you feel, providing up to 13dB of
boost or cut at 40Hz.
6. MID: Adjust the output level of your
upper-bass tones with this control: the
center position is “flat” (no boost or cut).
Turning the control to the left reduces the
upper-bass output; turning to the right
increases the upper-bass output. The
Mid control provides up to 11dB of
boost or cut at 260Hz, which changes
the “voice” of your instrument’s sound.
By boosting the Mid control you can
make the sound of your bass cut through
the rest of the band, without getting a
whole lot louder.
7. HIGH: Adjust the amount of high-frequency overtones with this control: the
center position is “flat” (no boost or cut).
Turning the control to the left reduces the
high-frequency output; turning to the
right increases the high-frequency output. The High control allows up to 15dB
of boost or cut at 5kHz, which allows you
to adjust the “crispness” of the sound of
your bass. Players looking for a sharp,
slapping sound may tend to want this
control turned up farther than those who
seek a more traditional sound.
8. HIGH BOOST: Turning on the High
Boost greatly enhances the upper-harmonic overtones of your bass, increasing
such subtleties as the sounds of your fingers on the strings or the strings striking
the fretboard. High Boost produces an
additional 10dB of gain at 10kHz, making the “crisp” characteristics of your
bass even more pronounced.
MASTER LEVEL SECTION:
9. PEAK LED: This LED indicator will
light when you’re nearing the highest
desirable level for your input signal and
are in danger of overdriving the preamp’s solid state circuitry. (This can
cause the output of the amplifier to
sound distorted.) To get the maximum
benefit from the BT-350’s tube preamp
section (good, clean sound with the
“feel” of natural tube compression),
adjust the Tube Drive control (#3) until
this LED begins to flash when you’re hitting your strings pretty hard.
10. MASTER LEVEL: This is the BT-350’s
master volume control. The output level
of the amplifier through your main
speakers, the Biamp Outputs and the
Effects Loop Send are simultaneously
adjusted by this control: at the full-left
position there will be no output; rotating
the control to the right increases the volume level.
The Front Panel:
44
BT-350
BT-350 ThunderBass Amplifier
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