Crate Amplifiers Musical Instrument Amplifier GFX 20 User Manual

GFX-20  
GUITAR AMPLIFIER WITH  
DIGITAL SIGNAL PROCESSING  
OWNER’S MANUAL  
Congratulations!  
You are now the proud owner of the Crate GFX-20 guitar amplifier. This small but  
versatile amplifier features two separate channels – one crystal clear and the other with  
our patented “Flex-Wave” distortion – combined with a three-band EQ and an easy to  
operate DSP section which lets you dial in a variety of digital effects such as delay,  
flange, chorus and reverb. A special damping circuit simulates the “current source” type  
output of a tube amp, giving you solid state reliability combined with classic tube  
sounds.  
Your GFX-20 is Musician Made in the U.S.A., 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 amplifier, we strongly urge you to go over  
the information contained in this manual before you begin playing.  
And thank you for choosing  
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GFX-20 Amplifier  
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1: INPUT: Connect your guitar here using a  
shielded instrument cable.  
5: LEVEL: This control sets the output vol-  
ume level from the Clean channel: in the far-  
left position there will be no output; as you  
turn the control to the right the output level  
increases. The far right setting is maximum  
output - as you increase the level, roll back  
the Low control (#6).  
OVERDRIVE CHANNEL: A high gain chan-  
nel giving you sounds from a slight edge to  
serious overdrive.  
2: GAIN: This control sets the amount of  
compression and distortion from the amplifi-  
er. With the control towards far left, the  
sound will have a thick compressed quality.  
As you turn the control to the right the  
amount of distortion increases. Crate’s  
exclusive “Flex-Wave” circuitry uses sequen-  
tial cascading gains to deliver distortion  
which is rich in harmonics and “touch sensi-  
tive.” Use this control along with the Level  
(#3) to create a wide variety of sounds.  
EQUALIZATION  
6: LOW: Adjust the low frequency output  
level with this control: turning the control to  
the left reduces the low frequency output;  
turning it to the right increases the low fre-  
quency output. The Low control allows a  
total range of 25dB of boost or cut at 80Hz.  
Due to the massive amount of low end avail-  
able, you may want to “roll off” the bass at  
high volumes.  
3: LEVEL: This control sets the output vol-  
ume level from the Overdrive channel: in the  
far left position there will be no output; as you  
turn the control to the right the output  
increases. Use this control along with the  
Gain control (#2) to create a wide variety of  
sounds.  
7: MID: Adjust the mid frequency output  
level with this control: the center position is  
“flat” (no boost or cut). Turning the control to  
the left reduces the midrange output; turning  
it to the right increases the midrange output.  
The Mid control allows for 19dB of boost or  
cut at 900Hz.  
4: OVERDRIVE SELECT: When this push-  
button switch is pressed in the Overdrive  
channel is engaged. The clean channel is  
selected when this switch is out.  
8: HIGH: Adjust the high frequency output  
level with this control: in the center position  
the high frequency output will be “flat” (no  
boost or cut). Turning the control to the left  
reduces the high frequency output; turning it  
to the right increases the high frequency out-  
put. The High control allows a total range of  
23dB of boost or cut at 5kHz.  
CLEAN CHANNEL: A normal gain channel  
designed to give you crystal clear sounds to  
medium distortion.  
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GFX-20 Amplifier  
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9: DSP MODE: Select the type of digital  
effect(s) desired with this control. Each cat-  
egory and its central location is called out  
(delay, flange, etc.) by the markings around  
the control, with variations, as follows:  
12: ON LED: The word “ON” will glow when  
you turn on the GFX-20, showing you that  
the amplifier is activated and ready to play.  
13: POWER: This heavy-duty rocker-type  
switch is used to turn the amplifier ON in the  
left position, off in the right position. The ON  
LED (#12) works with this switch as a visual  
indicator.  
• Bypass (DSP off)  
• Slapback delay  
• Long delay w/regeneration  
• Flange  
• Slow Chorus  
• Fast Chorus  
• Chorus w/small room reverb  
• Small room reverb  
• Large room reverb  
14: POWER CORD: (Rear panel, not  
shown: This heavy-duty, grounded, three-  
wire power cord is to be plugged into ONLY  
a safely-wired, grounded 120 volt, 60 cycle  
AC power outlet. DO NOT attempt to defeat  
the ground connection of this cable! If your  
GFX-20 was purchased outside the United  
States, see the unit’s rear panel for its power  
rating and follow the above guidelines.  
10: HEADPHONES: For private practice  
sessions, plug a pair of stereo headphones  
into this jack. The internal speaker is discon-  
nected whenever headphones are being  
used.  
11: EXTERNAL SPEAKER*: You may con-  
nect the GFX-20 to an external speaker with  
a rated impedance of at least 4 ohms using  
this jack. The internal speaker is disconnect-  
ed whenever an external speaker is used.  
*WARNING:  
DO NOT attempt to  
use headphones in  
the Speaker jack!  
Permanent hearing  
damage could result!  
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GFX-20 Amplifier  
GFX-20 TECHNICAL SPECIFICATIONS  
Output Power Rating  
>20 watts RMS @ 5% THD 4 ohms, 120VAC  
Gain, Overdrive Channel  
Gain, Clean Channel  
86dB +/-6dB @ 1kHz  
46dB +/-6dB @ 1kHz  
Tone Control Range, Low  
Tone Control Range, Mid  
Tone Control Range, High  
25dB @ 80Hz  
19dB @ 900Hz  
23dB @ 5kHz  
Signal To Noise, Overdrive Channel  
Signal To Noise, Clean Channel  
>50dB  
>65dB  
Maximum Signal Accepted  
Internal Speaker  
>1.2 volts RMS min. @ 400Hz  
10” Crate Custom Design 4 ohm  
Input Power Requirements  
120 VAC, 60Hz, 20VA  
100/115VAC, 50/60Hz, 20VA  
230VAC, 50/60Hz, 20VA  
Size and Weight:  
15” H x 16.75” W x 9.5” D, 21 lbs.  
The GFX-20 is covered with a durable black Tolex material: wipe it clean with a lint-free cloth. Never  
spray cleaning agents onto the cabinet. Avoid abrasive cleansers which could damage the finish.  
CAUTION  
PRECAUCION  
ATTENTION  
RISK OF ELECTRIC SHOCK  
DO NOT OPEN  
RIESGO DE CORRIENTAZO  
NO ABRA  
RISQUE D'ELECTROCUTION  
NE PAS OUVRIR  
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC  
SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOIS-  
TURE. TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT  
REMOVE COVER. NO USER-SERVICEABLE PARTS INSIDE.  
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.  
PRECAUCION: PARA REDUCIR EL RIESGO DE INCENDIOS  
O
DESCARGAS  
LA  
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.  
ELECTRICAS, NO PERMITA QUE ESTE APARATO QUEDE EXPUESTO  
A
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.  
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 UNIT REQUIRES 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 OPERA-  
TION AND TO AVOID INJURY.  
THIS APPARATUS DOES NOT OPERATE NORMALLY AND REQUIRES SERVICE WITH ANY PHYSICAL DAMAGE FROM IMPACT OR  
ANY EXPOSURE TO 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 PRO-  
TECTION IS RECOMMENDED IF UNIT IS OPERATED AT HIGH VOLUME.  
EXPLANATION OF GRAPHICAL SYMBOLS:  
EXPLICACION DE SIMBOLOS GRAFICOS:  
EXPLICATION DES SYMBÔLES GRAPHIQUES:  
"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"  
"DANGEROUS VOLTAGE"  
“VOLTAJE PELIGROSO”  
"DANGER HAUTE TENSION"  
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Crate continually develops new products, as well as improves existing ones. For this reason, the  
specifications and information in this Crate manual are subject to change without notice.  
©1998 SLM ELECTRONICS, A DIVISION OF ST. LOUIS MUSIC, 1400 FERGUSON, ST. LOUIS, MO. 63133  
P/N 47-452-01 • 03/02  
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