All Tube
Guitar Amplifier
User’s Guide
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BV120H All Tube Guitar Amplifier
Introduction:
The BV120H is an all-tube, feature-packed professional stage performers' amplifier. Rugged construction,
reliable American craftsmanship and two powerful channels of pure tube power are some of the trademarks
of this new and impressive piece of musician's equipment. This amplifier features two distinctly different
12AX7 tube-driven channels: one with classic tube rhythm sounds and one offering you some of the finest
lead and overdrive sounds of any stock amplifier.
Each channel features an all-tube preamp section with separate reverb level controls and three bands of
equalization for total tone control. The master Presence control lets you custom tailor the sound of your gui-
tar to suit your particular needs. The effects loop can be quickly bypassed via the front panel switch or an
optional footswitch and features a switchable “pad” for use with either floor pedals or rack-mounted effects.
The Line Out signal is tapped directly from the speaker outputs, then attenuated and frequency-compen-
sated to replicate the sound of a miked speaker cabinet. Dual speaker jacks and an impedance selector
switch allow the use of multiple cabinets totalling 8 or 16 ohms. The BV120H packs a solid 100 watts of out-
put power.
Features:
Here's a quick overview of the BV120H's features and controls. Additional information can be
found on the pages indicated.
• All-Tube Preamp and Power Amp: Classic tube sounds with Crate’s legendary performance and
reliability.
• Two Completely Separate Channels: Independent level, tone and reverb controls (page 4).
• Presence Control: Provides even greater tone control and flexibility by allowing you to vary the
upper harmonics of your guitar (page 4).
• Footswitch Control: Remote channel selection and Effects Loop On/Off is available through the
use of an optional two-button footswitch (such as Crate’s CFP-2) (page 5).
• Switchable Effects Loop with Pad: Footswitch or front panel button controlled, the external
effects loop can be switched in or out with ease. A switchable pad provides optimum performance
from line-level rack mounted effects as well as floor-dwelling foot pedals (pages 4,5).
• Impedance Selector Switch: Proper impedance matching is essential for optimum performance
and life expectancy of a tube amplifier. These amps allow the use of 8 or 16 ohm speaker config-
urations (page 5).
• Line Out Jack: Taken directly from the speaker output jacks, the Line Out signal is frequency
compensated to sound like a “miked” speaker cabinet. Use this jack to connect to the house mix-
ing board, a recording console or another performer’s powered monitor (page 5).
• DC Filament Supply: The first preamp tube has a DC filament supply for reduced hum.
• High Cosmetic Appeal and Stage Presence: The unique cosmetics of the BV120H serve as a
tribute to your good taste in musical equipment.
• Musician Made in the U.S.A.
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BV120H All Tube Guitar Amplifier
The Front Panel:
1
2
3
4 5
6
7
8
9
10
11
12
13
14
15
16
17
18
1. POWER: This switch applies AC volt-
age to the amplifier, and should always be
turned on first. The switch illuminates
when the AC power is on.
Channel 2:
Channel 1:
8. LEVEL: Set the output signal level of
channel 2 with this control. At the "0" posi-
tion (full left) very little or no signal will be
heard; as you rotate the control clockwise
(towards center) the output level of chan-
nel 2 increases. Use this control along
with your guitar's volume and the channel
2 gain control (#12) to produce a wide
variety of sounds.
14. BASS: Adjust the bottom end re-
sponse with this control. The low control
covers a range of 16dB at 100Hz. This
sets the amount of bass heard (and felt)
from the amp.
2. STANDBY: This switch activates the
amplifier, and should always be turned on
last. The switch illuminates when the high
voltage power is passing through to the
tubes.
15. MID: Adjust the midrange response
with this control. The mid control covers a
range of 20dB at 300Hz. This controls the
“voice” of your guitar.
NOTE: When you first power up this
amplifier, leave the Standby switch
OFF for at least 20 seconds. This
gives the power tubes a chance to
prepare themselves for action.
9. BASS: Adjust the bottom end response
with this control. The low control covers a
range of 15dB at 100Hz. This sets the
amount of bass heard (and felt) from the
amp.
16. TREBLE: Adjust the high end
response with this control. The high con-
trol covers a range of 10dB at 10kHz. This
controls the “bite” of your guitar.
3. PRESENCE: Increase the level of
upper harmonics with this control. The
presence control allows a boost of up to
5dB at 10kHz.
17. LEVEL: Set the output volume level of
channel 1 with this control.
10. MID: Adjust the midrange response
with this control. The mid control covers a
range of 13dB at 500Hz. This controls the
“voice” of your guitar.
18. INPUT: Connect your guitar or wire-
less receiver into this standard 1/4" jack by
means of a shielded instrument cable.
4. EFFECTS LOOP PAD: This switch
activates a 12dB pad on the effects send
signal and corresponding gain recovery
on the return. In the out position the signal
is full strength which is best suited for line
level rack mountable effects. With the
switch depressed the signal is lower which
is best suited for foot pedal type effects.
11. TREBLE: Adjust the high end
response with this control. The high con-
trol covers a range of 10dB at 10kHz. This
controls the “bite” of your guitar.
12. GAIN: Adjust the overdrive (distortion)
level with this control. With the control
towards “0” (to the left) the signal is rela-
tively clean. As you rotate the control
clockwise the distortion increases, along
with the overall output level. Rotate the
control towards “10” and you’ll increase
the distortion even more.
5. EFFECTS LOOP SWITCH: This switch
controls the effects return signal of the
effects loop. The loop is only active when
the switch is pressed in. When a
footswitch is used, this switch is disabled.
The adjacent yellow LED illuminates when
the loop is in use.
13. CHANNEL SELECT: Switch between
channels with this push-button switch. The
adjacent amber LED illuminates when
channel 1 is selected (switch in the out
position), the red LED illuminates when
channel 2 is selected (switch depressed).
When a footswitch is used for channel
switching, this switch is disabled.
6,7. REVERB 2, REVERB 1: Adjust the
amount of reverberation on each channel
with these controls: at the "0" position the
signal is "dry" (no reverb). As you rotate
the control clockwise, the amount of
reverb increases.
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BV120H All Tube Guitar Amplifier
The Rear Panel:
19
20
21
22
23
24
25
26
27
19. IMPEDANCE SELECTOR: For the
best performance and least strain on
your amplifier, you MUST properly match
the impedance of your amplifier to that of
your speaker cabinet(s). Set the selector
switch to the 8 or 16 ohm position,
depending on the total impedance of
your speaker cabinet(s). The chart below
can help you determine that impedance
based on the following combinations of
speakers connected in parallel.
22. LINE OUT JACK: This 1/4” jack sup-
plies a line-level output signal from the
power amp for patching into a mixing
board, recording console or external
amplifier. The signal is tapped directly
from the speaker outputs, then attenuat-
ed and electronically compensated to
simulate the sound of a “miked” cabinet.
25. FOOTSWITCH JACK: Connect a
stereo 1/4” (tip/ring/sleeve) here from a
two-button footswitch (such as the Crate
CFP-2) for remote control of channel
switching and the effects loop. The tip of
the jack is for the channel switching; the
ring is for the effects loop. When a
footswitch is connected here, the front
panel channel select and effects loop
switches are disabled.
23. EFFECTS LOOP RETURN:
Connection from an external effects
device is made via this jack. Connect a
shielded instrument patch cord from the
output jack of the effect to the return
jack. This jack is active only when the
effects loop is switched in. The return
jack also doubles as a "power amp in"
jack, to feed a line-level signal directly
into the BV120H's internal power amp.
This is useful when "slaving" two ampli-
fiers together.
26. AC LINE IN: This grounded power
cord is to be plugged into a grounded
power outlet, wired to current electric
codes and compatible with voltage,
power, and frequency requirements stat-
ed on the rear panel. Do not attempt to
defeat the safety ground connection.
CAB. IMP.
8 OHMS
16 OHMS
16 OHMS
32 OHMS
32 OHMS
# OF CABS. TOTAL IMP.
1
1
2
2
4
8 OHMS
16 OHMS
8 OHMS
16 OHMS
8 OHMS
27. FUSE: This fuse protects the amplifi-
er against damages caused by overload
conditions in the unit. If the fuse fails,
replace it only with the same size and
type as indicated on the rear panel. If the
fuse fails continually, the line voltage
may be incorrect, or the amp may need
servicing.
20. MAIN SPEAKER JACK: Use this
jack to connect the amplifier to your pri-
mary speaker cabinet by means of a
heavy gauge speaker cable. Always
keep the impedance at 8 or 16 ohms,
with the impedance selector switch (#19)
at the proper setting.
24. EFFECTS LOOP SEND: Connection
to an external effects device is made via
this jack. Connect a shielded instrument
patch cord from the send jack to the
input jack of the effect. This jack is
always active. The send jack also dou-
bles as a "preamp out" jack, to feed a
post-eq, pre-amplified signal to a mixing
board, recording console or external
amplifier.
NOTE: Use the MAIN SPEAKER jack
first. Then, if an extension speaker
is desired, connect it to the EXT.
SPEAKER jack.
21. EXT. SPEAKER JACK: Use this
jack to connect the amplifier to a sec-
ondary speaker cabinetby means of a
heavy gauge speaker cable, after a
speaker has been connected to the main
speaker jack (#20).
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BV120H All Tube Guitar Amplifier
Important Information About Tubes And Tube Products:
A Brief History Of The Tube:
In 1883, Edison discovered that electrons would flow from a suspended filament when enclosed in an evacuated lamp. Years later, in 1905,
Fleming expanded on Edison's discovery and created the "Fleming Valve". Then, in 1907, Dr. Lee de Forest added a third component – the grid
– to the "Fleming's Valve" and the vacuum tube was a fact of life. The door to electronic amplification was now open.
During World War II, data gleaned from their intensive research on the detectors used in radar systems led Bell Telephone Laboratories to the
invention of the transistor. This reliable little device gained quick support as the new component for amplification. The death of the vacuum tube
seemed imminent as designers, scientists, and engineers reveled in the idea of replacing large, fragile glass tubes with these small, solid-state
devices.
However, there were (and still are) many serious listeners who realized that the sound produced by a "transistor" amplifier is significantly differ-
ent from that produced by a tube amplifier with identical design specifications. They considered the sound produced by these new solid-state
devices to be hard, brittle, and lifeless. It was determined that solid-state devices produced a less musical set of harmonics than tubes. When
pushed past their limits, they tend to mute the tone and emphasize the distortion.
Tubes, on the other hand, produce a more musical set of harmonics, the intensity of which can be controlled by the player. This characteristic
adds warmth and definition to the sound which has become the hallmark of tube amplifiers. When tubes are driven into clipping, the harmonic
overtones can be both sweet and pleasing or intense and penetrating, depending on the musician’s musical taste and playing technique.
Over the years, application engineers have designed a number of outstanding solid-state amplifiers that sound very, very good. Some use spe-
cial circuitry which enables them to simulate the distortion characteristics of a tube amplifier. However, the tube amplifier, still held in the high-
est esteem by many musicians, offers a classic "vintage" sound in a contemporary market.
Tube Types And Usage:
Tube amplifiers are based primarily on two types of tubes – preamplifier tubes and power tubes. The tubes used in preamplifiers (12AX7,
12AU7, 12AT7, etc.) are smaller than the power tubes. These tubes amplify the signal from your instrument and shape the sound. They are
inherently microphonic (mechanically pick up and transmit external noises). Since these tubes are used in the critical first stages of a tube
amplifier's circuitry, it is very important to use high-quality, low noise/low microphonic tubes for this application. Although tubes of this quality
may be difficult to find and typically cost more than "off-the-shelf" tubes, the improvement in performance is worth the investment.
Preamplifier tubes are also used to drive the power tubes. When used in this application, a 12AX7 will produce a more distorted tone than a
12AT7, which produces a clearer, sweeter sound. A 12AU7 is even cleaner and brighter than a 12AT7, giving more definition to the sound. (In
some cases it is possible to change the sound by changing the type of preamp and/or driver tubes. When making any modification to your
equipment, it is highly recommended that you consult with a qualified service center.)
The power tubes are the largest tubes used in an amplifier. These tubes convert the low-level, conditioned signal from the preamplifier into a
level that is sufficient to drive the speakers. There are several types of power tubes available, each of which offers a different
performance/sound characteristic. For example, the EL34 power tube produces a great Classic rock sound. When an EL34 is driven into dis-
tortion it produces a unique sound ("crunch"). When compared to the 6L6, the EL34 distorts more quickly, exhibits a "looser" low-end
response and produces more harmonics at mid and high frequencies ("creamier" sound). These differences become more noticeable at high-
er volumes.
The 6L6 tubes produce a big low-end thump and have a very good dynamic range. They offer a more traditional "American Rock" sound. The
6V6 tubes produce a creamy sound with nice distortion. On the other hand, the KT88 produces a big low-end but sounds more like an EL34
in the mid and high frequencies.
The 6550 power tubes are more rugged and stay cleaner sounding even at full power. When they do distort, the sound produced is more solid
and has a tighter low end; more of a "heavy metal" type distortion with lots of power.
Some tubes are available in matched sets. These tubes have been extensively tested for optimum performance and longevity.
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BV120H All Tube Guitar Amplifier
Important Information About Tubes And Tube Products (Continued):
The Nature Of Tubes: Why (And When) To Replace Them:
Tubes are made up of a number of fragile mechanical components that are vacuum-sealed in a glass envelope or bubble. The tube's longevi-
ty is based on a number of factors which include how hard and often the amplifier is played, vibration from the speakers, road travel, repeated
set up and tear down, etc.
Any time you notice a change in your amplifier's performance, check the tubes first.
If it's been a while since the tubes were replaced and the sound from your amplifier lacks punch, fades in and out, loses highs or lows or pro-
duces unusual sounds, the power tubes probably need to be replaced. If your amplifier squeals, makes noise, loses gain, starts to hum, lacks
"sensitivity", or feels as if it is working against you, the preamplifier tubes may need to be replaced.
The power tubes are subjected to considerably more stress than the preamplifier tubes. Consequently, they almost always fail/degrade first. If
deteriorating power tubes aren't replaced they will ultimately fail. Depending on the failure mode, they may even cause severe damage to the
audio output transformer and/or other components in the amplifier. Replacing the tubes before they fail completely has the potential to save
you time, money and unwanted trouble. Since power tubes work together in an amplifier, it is crucial that they (if there is more than one) be
replaced by a matched set. If you're on the road a lot, we recommend that you carry a spare matched set of replacement power tubes and
their associated driver tubes.
After turning off the power and disconnecting the amplifier from the power source, carefully check the tubes (in bright light) for cracks or white
spots inside the glass or any other apparent damage. Then, with the power on, view the tubes in a dark room. Look for preamplifier tubes that
do not glow at all or power tubes that glow excessively red.
Whenever you replace the power tube(s):
• Always have the amplifier's bias voltage checked by a qualified service center. Improper bias voltage will cause degradation in performance
and possibly damage the tubes and/or the amplifier. (See the section below entitled, "The Importance of Proper Biasing", for more information
on this subject).
• We highly recommend that you replace the driver tube(s) as well. The driver tube determines the shape and amplitude of the signal applied
to the power tube(s) and has to work almost as hard as the power tube(s).
You can check your preamplifier tubes for microphonics by turning the amplifier on, turning up the gain and tapping lightly on each tube with
the end of a pencil or a chop stick (my favorite). You will be able to hear the tapping through your speakers, which is normal. It is not normal
for a tube to ring like a bell after it’s tapped. If it does ring then it’s microphonic and should be replaced. Remember to use only high quality,
low microphonic tubes in the preamplifier section.
Even though power tubes are rarely microphonic, you should check them anyway. The power tubes can be checked for microphonics just like
pre-amp tubes.
In the case of very high gain amps, you may be able to reduce the amount of noise generated by simply swapping the preamp tubes around.
The Importance Of Proper Biasing:
For the best performance and longest tube life, proper biasing is imperative. Bias is the negative voltage which is applied to the power tube’s
control grid to set the level of idle current. We cannot over emphasize the difference in warmth of tone and dynamic response that come with
proper biasing. If the bias is set too high (overbiased), the sound from the amp will be distorted at all levels. If the bias is set too low, (under
biased) the power tubes will run hot (the plates inside the tubes may glow red due to excessive heat) and the sound from the amplifier will
lack power and punch. The excessive heat greatly reduces tube life – from a few days to as little as a few hours in extreme cases. Setting the
bias on your amp is like setting the idle on your car. If it’s too high or hot it’s running away with you and if it’s too low or cold it will choke when
you step on it.
The bias is adjusted at the factory in accordance with the type of power tube(s) installed in your amplifier. It is important to point out that tubes
of the same type and specification typically exhibit different performance characteristics. Consequently, whenever power tubes are replaced,
the bias voltage must be checked (unless the amplifier is equipped with "self-biasing circuitry) and readjusted to accommodate the operating
parameters of the replacement tubes.
Depending on the model and amplifier type, there may be hum balance controls, trim pots, or bias adjustment controls on its rear panel.
However, the bias adjustment should be performed only by qualified service personnel with the proper, calibrated test equipment.
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BV120H All Tube Guitar Amplifier
Important Information About Tubes And Tube Products (Continued):
Survival Tips For Tube Amplifiers:
To prolong tube life, observe these tips and recommendations:
• Match the impedance of your speaker cabinet(s) to your amplifier. Improper impedance matching will contribute to early tube degradation and may
cause premature tube failure.
• Make sure the speaker(s) are properly connected prior to turning on the amplifier.
• After playing the amplifier, allow sufficient time for it to properly cool down prior to moving it. A properly cooled amplifier prolongs tube life due to the
internal components being less susceptible to the damage caused by vibration.
• Allow the amplifier to warm up to room temperature before turning it on. The heat generated by the tube elements can crack a cold glass housing.
• Replace the output tube(s) before the performance degrades or the tubes fail completely. Replace the tube(s) on a regular basis (at least once per
year or as often as every 4 to 6 months if you play long and hard every day).
• Always have the bias checked after replacing the output tubes (unless the amplifier is equipped with "self-biasing circuitry"). This should be done
ONLY at a qualified service center. Improper biasing could result in the tubes running too hot, which greatly reduces the life of the tubes – or too
cold, which results in distorted sound regardless of level settings. Do not play the amplifier if it exhibits these symptoms – get the bias
checked/adjusted immediately to prevent tube failure and/or other damage.
• If the locating notch on the base of a power tube breaks off, replace the tube. This significantly reduces the risk of damaging your amplifier by incor-
rectly inserting the tube.
• Protect the amplifier from dust and moisture. If liquid gets into the amplifier proper, or if the amplifier is dropped or otherwise mechanically abused,
have it checked out at an authorized service center before using it.
• Proper maintenance and cleaning in combination with routine checkups by your authorized service center will insure the best performance and
longest life from your amplifier.
CAUTION: Tube replacement should be performed only by qualified service personnel who are familiar with the dangers of hazardous volt-
ages that are typically present in tube circuitry.
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BV120H All Tube Guitar Amplifier
Some Suggested Settings:
CRUNCHY EDGE:
SPARKLING CLEAN:
(as needed)
(as needed)
(as needed)
(as needed)
ROCK RHYTHM:
FAT CLEAN:
(as needed)
MASSIVE METAL:
(as needed)
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BV120H All Tube Guitar Amplifier
System Block Diagram:
CH.1
TUBE
STAGE
INPUT
CHANNEL
BASS MID TREBLE LEVEL
SWITCHING
TUBE
STAGE
CH.2
TUBE
STAGE
TUBE
STAGE
TUBE
STAGE
TUBE
STAGE
GAIN
BASS MID TREBLE LEVEL
PAD
SWITCHING
SEND
RETURN
EFFECTS
SWITCHING
EFFECTS
LOOP
REVERB
LEVEL 1
REVERB
LEVEL 2
MAIN
SPKR
OUT
POWER
AMP
IMPEDANCE
SELECTOR
EXT.
SPKR
OUT
PRESENCE
LINE
OUT
FREQUENCY
COMPENSATOR
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BV120H All Tube Guitar Amplifier
11
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BV120H All Tube Guitar Amplifier
BV120H TECHNICAL SPECIFICATIONS:
Output Power Rating
Gain
100W RMS @ 5% THD, 8 or 16 ohm load, 120 VAC
Channel 1
Channel 2
66dB, tones at “10” @ 1kHz
101dB, tones at “10” @ 1kHz
Tone Control Range
Channel 1
Channel 2
Bass
Mid
16dB @ 100Hz
20dB @ 300Hz
10dB @ 10kHz
5dB @ 10kHz
15dB @ 100Hz
13dB @ 500Hz
10dB @ 10kHz
5dB @ 10kHz
High
Presence
Input Impedance
1M ohm
Maximum Signal Accepted
Power Requirements
2.8V peak to peak
120VAC, 60Hz, 180VA
100/115VAC, 50/60Hz, 180VA
230VAC, 50/60Hz, 180VA
SIZE AND WEIGHT
30.25”W x 12”H x 10”D, 50 lbs.
The BV120H is covered with a durable Tolex material: wipe it clean with a lint-free cloth. Never
spray cleaning agents onto the cabinet. Avoid abrasive cleansers which would damage the finish.
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.
Declaration Of Conformity
#35, Effective 01-01-2001
Manufacturer’s Name:
Production Facility:
SLM Electronics
1901 Congessional Drive, St. Louis, MO 63146, USA
700 Hwy 202 W, Yellville, AR 72687, USA
1400 Ferguson Ave., St. Louis, MO 63133, USA
1400 Ferguson Ave., St. Louis, MO 63133, USA
Production Facility:
Shipping Facility:
Office Facility:
Product Type:
Audio Amplifier
Complies with the following Standards:
Safety:
EMC:
EN60065, E60065, C22.2, UL6500 and/or UL813
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
@2003 SLM Electronics, a division of St. Louis Music, Inc • 1400 Ferguson Avenue • St. Louis, MO 63133
47-631-06 • 120403
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