BT25/BT50
BASS AMPLIFIER
USER’S GUIDE
IMPORTANT SAFETY INSTRUCTIONS
• READ, FOLLOW, HEED, AND KEEP ALL INSTRUCTIONS AND WARNINGS.
• DO NOT OPERATE NEAR ANY HEAT SOURCE AND DO NOT BLOCK ANY VENTILATION OPENINGS ON THIS APPARATUS. FOR
PROPER OPERATION, THIS UNITREQUIRES 3” (75mm) OF WELL VENTILATED SPACE AROUND HEATSINKS AND OTHER AIR
FLOW PROVISIONS IN THE CABINET.
• DO NOT USE THIS APPARATUS NEAR SPLASHING, FALLING, SPRAYING, OR STANDING LIQUIDS.
• CLEAN ONLY WITH LINT-FREE DAMP CLOTH AND DO NOT USE CLEANING AGENTS.
• ONLY CONNECT POWER CORD TO A POLARIZED, SAFETY GROUNDED OUTLET WIRED TO CURRENT ELECTRICAL CODES AND
COMPATIBLE WITH VOLTAGE, POWER, AND FREQUENCY REQUIREMENTS STATED ON THE REAR PANEL OF THE APPARATUS.
• PROTECT THE POWER CORD FROM DAMAGE DUE TO BEING WALKED ON, PINCHED, OR STRAINED.
• UNPLUG THE APPARATUS DURING LIGHTNING STORMS OR WHEN UNUSED FOR LONG PERIODS OF TIME.
• ONLY USE ATTACHMENTS, ACCESSORIES, STANDS, OR BRACKETS SPECIFIED BY THE MANUFACTURER FOR
SAFE OPERATION AND TO AVOID INJURY.
• WARNING: TO REDUCE THE RISK OF ELECTRIC SHOCK OR FIRE, DO NOT EXPOSE THIS UNITTO RAIN OR MOISTURE..
• SERVICE MUST BE PERFORMED BY QUALIFIED PERSONNEL.
• 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.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC
SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE. TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT
REMOVE COVER. NO USER-SERVICEABLE PARTS INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
"IT IS NECESSARY FOR THE USER TO REFER TO THE INSTRUCTION MANUAL"
“ES NECESARIO QUE EL USUARIO SE REFIERA AL MANUAL DE INSTRUCCIONES.”
"REFERREZ-VOUS AU MANUAL D'UTILISATION"
EXPLANATION OF GRAPHICAL SYMBOLS:
EXPLICACION DE SIMBOLOS GRAFICOS:
EXPLICATION DES SYMBÔLESGRAPHIQUES:
"DANGEROUS VOLTAGE"
“VOLTAJE PELIGROSO”
"DANGER HAUTE TENSION"
=
=
PRECAUCION
RIESGO DE CORRIENTAZO
NO ABRA
PRECAUCION: PARA REDUCIR EL RIESGO DE INCENDIOS O DESCARGAS
ELECTRICAS, NO PERMITA QUE ESTE APARATO QUEDE EXPUESTO A LA
LLUVIA O LA HUMEDAD. PARA DISMINUOIR EL RIESGO DE CORRIENTAZO.
NO ABRA LA CUBIERTA. NO HAY PIEZAS ADENTRO QUE EL USARIO PUEDO
REPARAR DEJE TODO MANTENIMIENTO A LOS TECHNICOS CALIFICADOS.
ATTENTION
RISQUE D'ELECTROCUTION
NE PAS OUVRIR
ATTENTION: PROTÉGEZ CET APPAREIL DE LA PLUIE ET DE L'HUMIDITÉ
AFIN D'ÉVITER TOUT RISQUE D'INCENDIE OU D'ÉLECTROCUTION. 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.
BT25/BT50
Bass Amplifier
Table Of Contents:
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
The Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . .4,5
Some Suggested Settings . . . . . . . . . . . . . . . . . . . . . .6
System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . .7
Technical Specifications . . . . . . . . . . . . . . . .back cover
2
3
Congratulations!
You are now the proud owner of the compact but powerful Crate
BT25/BT50 Bass Amplifier. The BT25/BT50 features two different channels: a distortion channel, featuring Crate’s exclusive Shape control for
quick and easy access to the tone you need, and a clean channel with
a four-band rotary EQ. Another unique and valuable feature of this
amplifier is the Octave control. This feature electronically creates a second signal that is one octave lower than the original signal. An active
electronic tuner, conveniently located on top of the amplifier, allows you
to get in tune and stay in tune “on the fly.” Front panel jacks are provided for connecting a CD player and a pair of headphones, thereby optimizing your practice time.
Like all Crate products, your BT25/BT50 is designed by musicians
and built using only the best components. Extensive testing at the hands
(and ears) of skilled technicians and musicians insures you that this
amplifier is the absolute best it can be.
In order to get the most out of your new bass amp, we urge you to
check out the information in this manual before you begin playing.
And thank you
for choosing Crate.
Declaration Of Conformity
#28, Effective 01-01-2001
Manufacturer’s Name: SLM Electronics
Production Facility: 1901 Congressional Drive, St. Louis, MO 63146, USA
Production Facility: 700 Hwy 202 W, Yellville, AR 72687, USA
Shipping Facility: 1400 Ferguson Ave., St. Louis, MO 63133, USA
Office Facility: 1400 Ferguson Ave., St. Louis, MO 63133, USA
Product Type: Audio Amplifier
Complies with the following Standards:
Safety: EN60065, E60065, C22.2, UL6500 and/or UL813
EMC: Directive 89/336/EEC, EN55103, EN55013, EN61000,
and/or FCC 47CFR 15B clA
Supplementary information provided by:
SLM Electronics - R & D Engineering
1901 Congressional Drive, St Louis, MO 63146, USA
Tel.: 314-569-0141, Fax: 314-569-0175
BT25/BT50
Bass Amplifier
BT25/BT50
Bass Amplifier
4
1. INPUT: Use this 1/4” jack to connect your bass to the amplifier by means of a shielded instrument cable.
2. GAIN: Use this control to adjust the amount of distortion for the Distortion channel. As you rotate the control
clockwise the amount of distortion increases.
3. SHAPE: Use this control to adjust the tone of the Distortion channel, from a studio “V”-shaped tone to a
more “live,” more present sound.
4. LEVEL: Use this control to adjust the output level of the Distortion channel.
5. CHANNEL SWITCH: Use this switch to select either channel. With the switch in the out position, the Clean
channel is selected. When the switch is depressed, the Distortion channel is selected. The adjacent LED illuminates when the Distortion channel is selected. NOTE: When using a footswitch: when this switch is
depressed, the footswitch switches between the Distortion channel and the Clean channel; when this button
is in the out position, the Clean channel is always active, and the footswitch turns the Distortion channel on
and off, allowing you a blend of both channels.
6. LEVEL: Use this control to adjust the output level of the Clean channel, and as part of the Octave level control (see #11).
NOTE: The BT25/BT50 employs an internal noise gate to keep residual noise to a minimum. Regardless of
which channel is selected, the Clean channel’s Level control (#6) must be turned up above “0” in order for the
noise gate to trigger.
7. LOW: Use this control to adjust the low frequency output of the Clean channel.
8. LOW MID: Use this control to adjust the lower-midrange frequency output of the Clean channel.
9. HIGH MID: Use this control to adjust the upper-midrange frequency output of the Clean channel.
10. HIGH: Use this control to adjust the high frequency output of the Clean channel.
11. OCTAVE: The BT25/BT50 features internal circuitry which creates a second signal which is one octave
lower than the input signal. Use this control in conjunction with the Clean channel’s Level control (#6) to adjust
the level of the octave signal.
12. MASTER: Use this control to adjust the overall output level of the amplifier.
The Front Panel:
1 2 3 4 5 6 7 8
BT25/BT50
Bass Amplifier
5
13. CD INPUT: Use these RCA jacks to connect the line level (or headphones) output of a CD player, tape
deck or rhythm machine to the amplifier. The signal level from these jacks is adjusted by the Master control
(#12). If the signal from the source connected to these jacks is too strong, use the output level control on the
source to adjust the signal to obtain the proper level for a good mix.
14. HEADPHONES: Use this jack to listen to the amplifier through a pair of stereo headphones. The internal
speaker is disconnected when the headphones jack is used.
CAUTION: To avoid possible damage to your hearing, do not use head-
phones for extended periods of time at extremely loud listening levels.
15. POWER: Use this switch to turn the amplifier on and off. The adjacent LED illuminates when the amplifi-
er is turned on.
16. ELECTRONIC TUNER (top panel): This active
electronic tuner is on whenever the amplifier is turned
on, allowing you constant, “real-time” tuning. The tuner
is fully chromatic – use the flat and sharp indicators
until the LED between them illuminates, indicating
proper tuning.
The Rear Panel (not shown):
17. AC LINE CORD: The grounded power cord should only be plugged into a grounded power outlet that
meets all applicable electrical codes and is compatible with the voltage, power, and frequency requirements
stated on the rear panel. Do not attempt to defeat the safety ground connection.
18. FOOTSWITCH: Connect a two-button footswitch (such as the Crate CFP-2) here for remote control of the
channel selection/“blend” (see #5) and octave on/off. (When the Channel Switch [#5] is depressed, the
footswitch switches between the Clean channel and the Distortion channel; when the switch is in the out position, the Clean channel is always active, and the footswitch turns the Distortion channel on and off, allowing
you a blend of both channels.)
19. EXTERNAL SPEAKER: Use this jack to connect the amplifier to an external speaker cabinet (BT25 = 4
ohms minimum, BT50 = 8 ohms minimum). The internal speaker is disconnected when the external speaker
jack is used.
9 10 11 12 13 14 15
6
Suggested Starting Settings:
BT25/BT50
Bass Amplifier
Rock:
OUT
Jazz:
OUT
Country:
**
**
Funk:
Solo Fuzz:
Super Fat Fuzz:
OUT
**
OUT
**
IN
**
IN
*
BT25/BT50
Bass Amplifier
7
System Block Diagram:
INPUT
A BC D EF G
BUFFER
TUNER
LEVEL
NOISE
GATE
DISTORTION
GAIN
OCTAVE
LOW LOW
MID
SHAPE
FOOT
SWITCH
EQ
HIGH
MID
LEVEL
HIGH
CHANNEL
SWITCH
LEVEL
CD
INPUT
POWER
AMP
EXTERNAL
SPEAKER
MASTER
SPEAKER
ATTENUATOR
HEAD
PHONES
©2003 ST. LOUIS MUSIC, 1400 FERGUSON, ST. LOUIS, MO. 63133
47-376-01 • 012904
BT25/BT50
Bass Amplifier
BT25 BT50
Output Power Rating 25W RMS 2% THD, 4Ω, 120 VAC 50W RMS 2% THD, 4Ω, 120 VAC
Gain Distortion Channel 100dB 104dB
Clean Channel 60dB 63dB
CD Inputs 33dB 37dB
Tone Range Low 21dB @ 50Hz 21dB @ 50Hz
Lo Mid 23dB @ 150Hz 23dB @ 150Hz
Hi Mid 18dB @ 1kHz 18dB @ 1kHz
High 34dB @ 10kHz 34dB @ 10kHz
Signal to Noise Ratio 75dB 75dB
Input Impedance 220k ohms 220k ohms
Maximum Signal Accepted 15 volts peak-to-peak 15 volts peak-to-peak
Input Power Requirements 120 VAC, 60Hz, 45VA 120 VAC, 60Hz, 85VA
100/115VAC, 50/60Hz, 45VA 100/115VAC, 50/60Hz, 85VA
230VAC, 50/60Hz, 45VA 230VAC, 50/60Hz, 85VA
Internal Speaker Size 10” 12”
Type Crate Custom Crate Custom
Magnet 30 oz. 30 oz.
Voice Coil 1” 1.5”
RMS Rating 30 watts 50 watts
Impedance 4 ohms 8 ohms
Size 18” H x 18” W x 12-1/2” D 21” H x 18” W x 14” D
Weight 37 lbs 46 lbs
BT25/BT50 T
echnical Specifications:
www.crateamps.com
Specifications subject to change without notice
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