CA120D
Acoustic Amplifier
User’s Guide
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CA120D Acoustic Amplifier
About the Crate Acoustic CA120D:
Enough already? Not for us. The CA120D
features Crate’s Digital Signal Processing (DSP)
for a variety of digital reverbs, effects and
delays specifically designed for acoustic
instruments.
esigned for the performing artist,
Crate’s CA120D Acoustic Amplifier
gives you more of what you want.
D
More power. More clarity. More control. And,
more freedom. Imagine: microphone quality
sound, without feedback. And without being
“chained” to a mic stand!
More power: a 120 watt RMS power ampli-
fier drives a Studio Monitor-style 12” sub-
woofer for plenty of volume and low end
punch.
The CA120D was designed, evaluated, and
tweaked by music loving engineers. Each
amplifier is produced by skilled assemblers
using sophisticated assembly machines and
the finest components. Trained craftsmen
assemble and cover every cabinet by hand.
The finished product is tested – and played –
by skilled musicians/technicians. It is only
after the amplifier has passed this meticulous
design/assembly/performance/approval
process that we allow it to be shipped to our
customers.
More clarity: a specially designed tweeter
provides clean crisp highs and natural mid-
range blend. A tweeter level control allows
you to adjust the high frequency output to
suit your taste.
More control: two separate channels, each
with its own gain, tone, and reverb/effects
controls. An automatic feedback elimination
circuit with two filter select controls lets you
kill feedback without sacrificing sound quali-
ty. The filters can be controlled by means of a
footswitch provided with the unit.
The CA120D Acoustic Amplifier. Designed
to be the best, so you can sound your best!
A pair of CD Input jacks allows you to play
along with a compact disc, cassette tape, or a
rhythm machine.
To get this amplifier to sound its best,
read this owner’s guide prior to its use.
Still more: Footswitch jacks on the rear
panel provide control for the feedback circuit
as well as two “tracking” DSP presets. Level-
controllable XLR and 1/4” balanced line outs
allow you to patch into house sound boards
or recording consoles, plus an effects loop
line-in/line-out setup allows connection of
external effects. An external speaker jack lets
you connect the amplifier to another separate
speaker cabinet.
To keep this amplifier looking its best, avoid
abrasive cleansers. Wipe the cabinet clean
using a slightly dampened cloth. Never use
brass cleaners on the hardware since they
could damage their protective coatings.
Crate Acoustic amplifiers are Made With Pride in the U.S.A.
3
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CA120D Acoustic Amplifier
The Front Panel:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
NOTE: Channel 1 and Channel 2 are independent of each other up
to the Effects and Master sections. The text below (#1–10)
applies to both channels.
The Master Section - part one:
11: CD Input. Use these RCA jacks to connect a CD or tape player to the
amplifier. Use the CD Level control (#12) to adjust the level of the
player.
1: Low-Z. The signal from a low impedance microphone may be con-
nected here by means of a shielded, balanced microphone cable ter-
minated with an XLR connector. This jack has 15 volts phantom
power applied to pins 2 and 3. (Mics not requiring phantom power
will not be affected.)
2: Gain 1. This serves as the input level control for the XLR Input jack
(#1). For the best signal to noise ratio set this control so the Peak LED
(#5) flashes on strong signals.
12: CD Level. Use this control to adjust the signal level at the CD Input
jacks (#11).
13: Tweeter Cut. Use this control to reduce the output level of the inter-
nal high frequency driver. In the fully counter-clockwise position, the
tweeter is at its full output level. As you rotate the control clockwise,
the tweeter level decreases. Adjust this control to best suit your play-
ing environment.
3: High-Z. The signal from your acoustic instrument may be connected
here by means of a shielded signal cable. This input will accommo-
date a piezo pickup or an active system.
14: Feedback Filters. Use these switches to activate the CA120D’s
advanced feedback elimination circuitry. For complete details, see the
section entitled “To Eliminate Feedback” on page 6.
4: Gain 2. This serves as the input level control for the High-Z jack (#3).
For the best signal to noise ratio set this control so the Peak LED (#5)
flashes on strong signals.
5: Peak. This LED flashes when the signal level into the preamp
approaches clipping. Adjust the Gain controls (#2, #4) until a strong
signal causes this LED to flash.
6: Low. This serves as the bass control. Adjust this control to get the best
sounding bass response for this channel. Excessive boost of the low
control can cause an unnatural howling and should be avoided.
7: Mid. This serves as the midrange control. Adjust this control to get
the best projection and midrange tones for your instrument. The cen-
ter point of the mid control is chosen by the setting of the Contour
control (#8).
The Effects Section:
15: Mode. Use this control to select the type of Digital Signal Processing
effect applied to the output signal. For a listing of the effects, please
see the section entitled “The DSP Section” on page 6.
16: DSP Level. Use this control to adjust the amount of internal DSP
effect.
17: Aux In/Eff Ret. Use this control to adjust the mix of the line level signal
applied to the Effects Aux In/Eff Ret jack (#24, page 5) with the main
input signal.
The Master Section - part two:
18: Level. Use this control to set the overall output level of the amplifier.
8: Contour. Use this control to set the center point of the Mid control
(#7). Set this control at the frequency which gives you the most natu-
ral-sounding midrange tones.
9: High. This serves as the treble control. Adjust this control so your
high notes and harmonic overtones are lively but not overpowering.
10: DSP/Eff Send. Use this control to adjust the amount of internal
Digital Effect and/or external effect (if used).
4
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CA120D Acoustic Amplifier
The Rear Panel:
19
20
21
22
23
24
25
26
27
28
29
19: Power. Use this switch to turn the amplifier on (top of the switch
depressed) and off (bottom of the switch depressed.) The power
switch illuminates when the amplifier is on.
20: 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!
21: External Speaker. Use this jack to connect the amplifier to an external
speaker cabinet. This jack is wired in series with the internal speakers
which remain active when an external speaker is connected.
22: Feedback Filters Footswitch. Connect the three-button footswitch to
this jack for remote control of the feedback filters. The Feedback
Filters ON LED (#14, front panel) illuminates and the feedback circuit
is activated when a footswitch is connected to this jack. Footswitch
button #1 controls Feedback Filter 1, button #2 controls Filter #2. (See
illustration below.)
23: DSP A/B Bank Footswitch. Connect the three-button footswitch to
this jack for remote control of two DSP settings:
1.With footswitch button #3’s LED illuminated, select one of the DSP
settings
2.Step on footswitch button #3 - the LED will go out - select a differ-
ent DSP setting
3.Step on footswitch button #3 again - the LED illuminates, and the
DSP automatically changes back to the setting chosen in step 1.
4.Step on footswitch button #3 again - the LED goes out, and the DSP
automatically changes back to the setting chosen in step 2.
24: Effects Aux In/Eff Ret. When using an external signal processor or any
line level signal (drum machine, keyboard, etc), connect the output of the
device to this jack by means of a shielded signal cable.
25: Effects Send. When using an external signal processor, connect this
jack to the input of the effect by means of a shielded signal cable.
26: Line Out Level. Use this control to adjust the output level of the line
out signal. (This control works independently from the amplifier’s
master level control.)
27: High Z Bal Line Out. Use this jack to connect a high impedance, line
level signal to a house sound board, a recording console or an exter-
nal power amplifier by means of an 1/4” stereo plug-terminated
cable. (Ring is signal +, tip is signal -, and sleeve is ground.)
28: Gnd Lift. This switch, when depressed, electronically disconnects
both of the Line Out jacks’ (#27, #29) chassis ground connections. If
you experience excessive noise when using the Line Out jacks,
depress this switch.
Note: This is a STEREO jack: tip = Filter 1, ring = Filter 2, sleeve is
ground. Use only a footswitch equipped with a stereo 1/4” plug.
CA120D Rear Panel:
NOTE: The Feedback
circuit is activated
when a footswitch is
plugged into the
Feedback Filters
Footswitch jack ---->
29: Low Z Bal Line Out. Use this jack to connect a low impedance, line
level signal to a house sound board, a recording console or an exter-
nal power amplifier by means of an XLR-terminated cable. (Pin 1 is
ground, pin 2 is signal +, and pin 3 is signal -.)
1
1
2
3
2
Filter #1
on and off
Togg es
between
DSP
Filter #2
on and off
settings
5
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CA120D Acoustic Amplifier
To Eliminate Instrument Feedback:
One of the most common problems encountered when amplifying
acoustic instruments, especially in small environments, is feedback.
Acoustic instruments typically have inherent qualities which cause reso-
nant feedback at specific frequencies. Instrument tone controls and sound
board equalizers are helpful in getting rid of the problem, but they typi-
cally operate around relatively wide frequency bands. This almost always
means the musician must sacrifice sound quality in his quest to do away
with feedback. But since Crate’s feedback elimination circuit isolates only
the offending frequency, instrument feedback from the CA120D can be
eliminated without affecting the overall sound.
If you experience feedback while playing, depress the Feedback Filters On
switch. This actives the automatic feedback control circuit. Depress the
Feedback Filter 1 switch to isolate and control the offending frequency. If
feedback occurs again while the Filter 1 switch is depressed, depress the
Filter 2 switch to isolate and control the second offending frequency.
The LEDs above the switches illuminate when the switches are depressed.
When a footswitch is used in the Feefback Filters Footswitch jack (#22),
the ON LED illuminates when the plug is inserted into the jack and the
front panel switches are rendered inoperative.
The DSP Section:
The CA120D features Crate’s On-Board Digital Signal Processing
(DSP) technology that was designed specifically for use with
acoustic instruments and vocals. This provides a large selection
of digital reverbs, effects and delays. Select the type of effect
desired by rotating the Mode control (#15). The effects are
described below.
When a footswitch is used in the DSP A/B Back Footswitch jack (#23), a
separate DSP setting can be stored and recalled for each of the
footswitch’s two button positions (LED on, LED off). Refer to the steps on
page 5, item #23.
The following chart provides a list of the DSP settings along with a brief description of
each effect.
Reverb: R average room reverb
S
M
L
small dark hall reverb
medium hall reverb
large hall reverb
Delay: S 100 milisecond delay
200 milisecond delay
M
L1 335 milisecond delay
L2 500 milisecond delay
Rev/Dly: M reverb with 250 milisecond delay
L1 reverb with 400 milisecond delay
L2 reverb with 550 milisecond delay
Multi: Ch1 chorus effect
Ch2 chorus, 375 milisecond delay, reverb
Ch3 425 milisecond delay with chorus, reverb
Dblr adds second signal slightly out of sync with original
Bypass effects “off”
6
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CA120D Acoustic Amplifier
System Block Diagram:
Channels 1 and 2:
phantom
power
peak
low-z
tones
gain
DSP/eff
send
high-z
low mid cntr high
gain
mode
effects
send
high-z
bal
DSP
line out
level
foot
switch
low-z
aux in/
eff ret
bal
aux in/
eff ret
cd
gnd
lift
input
gain
high pass
low pass
hi-freq
driver
feedback
filters
limiter
on/off*
level
feedback
circuit
power
amp
low-freq
driver
tweeter
cut
foot
switch* filter
1
filter
2
external
speaker
*NOTE: Feedback circuit activated when footswitch plug is inserted into Feedback Filters Footswitch jack
7
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CA120D Acoustic Amplifier
Technical Specifications:
Output Power Rating:
Channels 1 & 2: Low:
Mid:
120 watts @ <1% THD
+/-15dB @ 80Hz
+15, -30dBdB from 450Hz – 1.2kHz (Contour)
+/-15dB @ 10kHz
High:
Input Impedance:
3.3M ohm High-Z, 3k ohm Low-Z
5mV High-Z, 2mV Low-Z
6mV High-Z, 3mV Low-Z
6V RMS (17V peak to peak)
22k ohm
Input Sensitivity:
Sens. to Eff Send/Line out:
Max Input Signal:
CD Input: Input Impedance:
Input Sensitivity:
150mV
Max Input Signal:
6V RMS (17V peak to peak)
11k ohm
AuxEff. Return: Input Impedance:
Input Sensitivity:
80mV RMS
Max Input Signal:
6V RMS (17V peak to peak)
2.2k ohm
Eff Send Out. Impedance:
Line Out Out. Impedance:
Feedback Filters:
220 ohm Low-Z, 2.2k ohm High-Z
10Hz to 4.8kHz range, -15dB cut per filter
Internal Woofer:
12” w/polypropylene cone, rubber surround, 45oz magnet, 2” voice coil,
4 ohms, 175w RMS, 95dB 1w 1m
Internal Tweeter:
Internal Crossover:
Power Requirements:
High efficiency Piezo, 110dB 1w 1m
Passive type
120VAC, 60Hz, 160VA
100/115VAC, 50/60Hz, 160VA
230VAC, 50/60Hz, 160VA
Size and Weight:
18”H x 17-1/2”W x 15-1/2”D, 45 lbs.
Crate continually develops new products, as well as improves existing ones. For this reason,
the specifications and information in this manual are subject to change without notice.
©2004 SLM Electronics
A Division of St. Louis Music Co.
1400 Ferguson Avenue
St. Louis, MO 63133
47-942-01 • 021604
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