U S E R ’ S G U I D E
V32H GUITAR AMPLIFIER HEAD
Congratulations!
You are now the proud owner of a Crate V32H Guitar Amplifier Head. This
amplifier packs a whole lot of vintage tube sound into its compact cabinet
– giving you an amp that’s portable and easy to operate yet still produces
incredible sounds! Hidden underneath the amp’s cabinet are a pair of
heavy duty slide-out mounting brackets which can be used to “piggy back”
the amplifier onto the top of the Crate V212 Guitar Speaker Enclosure -
see page 6 for additional information.
Like all St. Louis Music amplifiers, your V32H is designed by musicians,
and built using the finest components available. Extensive testing confirms
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
read the information contained in this manual before you begin playing.
And Thank You for choosing a Crate amplifier!
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V32H GUITAR AMPLIFIER HEAD
The Front Panel:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1. Input: Connect your instrument here by
9. Presence: This switch, when
depressed, increases the output level of
the high frequencies by 8dB at 10kHz, giv-
ing a more “glassy” sound to the amplifier.
This helps the output of the amplifier cut
through “acoustically dead” rooms.
means of a shielded signal cable.
2. Clean Volume: Use this control to adjust
the output level of the Clean Channel.
3. Clean/Overdrive: This switch, when de-
pressed, selects the Overdrive Channel.
When this switch is in the out position, the
Clean Channel is selected.
10. Overdrive Level: Use this control to
adjust the output level of the Overdrive
Channel.
4. Overdrive Gain: Use this control to
adjust the gain of the Overdrive Channel.
With the control towards the counter clock-
wise position, the gain is low and very little
distortion is present. As you rotate the con-
trol clockwise the gain increases, produc-
ing more overdrive distortion and a higher
output volume level.
11. Reverb: Use this control to adjust the
amount of reverberation applied to the sig-
nal. With the control fully counter clockwise
no reverb is applied. As you rotate the con-
trol clockwise the amount of reverb increas-
es.
12. Lamp: This lamp illuminates when the
amplifier is turned on.
5. Treble: Use this control to adjust the out-
put level of the high frequencies. This con-
trol provides 12dB of cut or boost at 6kHz.
13. On/Standby: Use this switch to acti-
vate the amplifier. The On/Off switch (#14)
should be turned on first. Allow 20 seconds
for the amplifier to warm up before turning
the Standby switch on.
6. Boost: This switch, when depressed,
increases the output by 10dB at 900Hz,
giving the middle frequencies more punch.
14. On/Off: Use this switch to turn the
amplifier on and off. This switch should be
turned on at least 20 seconds before turn-
ing the Standby switch (#13) on.
7. Mid: Use this control to adjust the output
level of the middle frequencies. This control
provides 10dB of cut or boost at 1kHz.
8. Bass: Use this control to adjust the out-
put level of the low frequencies. This con-
trol provides 8dB of cut or boost at 150Hz.
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V32H GUITAR AMPLIFIER HEAD
The Rear Panel:
16
17
18
19
15. AC Line Cord (not shown): 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 stat-
ed on the rear panel. Do not attempt to
defeat the safety ground connection.
16. Footswitch: Use this jack to connect
the supplied two-button footswitch for
remote control of channel switching and
the Boost function. The front panel
Clean/Overdrive and Boost switches
18. Line In: Use this 1/4” jack to connect
the output of an external effects proces-
sor to the amplifier.
19. 8 Ohm Speaker: Use this jack to
connect the external cabinet to the
amplifier by means of a heavy duty
Class 2 wiring speaker cable terminated
with 1/4” plugs. The total impedance rat-
ing for the external speaker(s) must be 8
ohms.
WARNING: The speaker output of this unit
can exceed 10 Watts and could be a shock
injury. Connection to speakers should be
performed by a skilled person in compliance
with local building codes. Class 2 wiring is
required for speaker cables. Use of external
speakers outside the ratings stated at the
speaker jack may result in a shock injury or
damage to the unit.
(#3,#6) are inoperative when
footswitch is connected.
a
17. Line Out: Use this 1/4” jack to send
a line level signal to a mixing board,
external power amplifier or powered
monitor, or to the input jack of an exter-
nal signal processor.
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V32H GUITAR AMPLIFIER HEAD
Piggy Back Mounting onto the V212 Speaker Cabinet:
The
V32H amp head is
designed to “piggy back” mount
onto Crate’s V212 enclosure. The
V32H has slide-out mounting
hardware which lock onto the
posts on the top of the V212.
Loosen the knobs on the posts,
slide the amp in place and lock
down the knobs.
The piggy-backed amp can
be rolled around on its casters
by the amp head’s handle, but
do not try to pick the combo up
by the amp head or its handle
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V32H GUITAR AMPLIFIER HEAD
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 evac-
uated 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 vac-
uum 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, sci-
entists, 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 "tran-
sistor" amplifier is significantly different from that produced by a tube amplifier with identical design specifica-
tions. 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 special circuitry which enables them to simulate the distortion characteris-
tics of a tube amplifier. However, the tube amplifier, still held in the highest 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 pro-
duce 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 distortion it produces a
unique sound ("crunch"). When compared to the EL84 and 6L6, the EL34 distorts more quickly, exhibits a
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V32H GUITAR AMPLIFIER HEAD
Important Information About Tubes and Tube Products (continued):
"looser" low-end response and produces more harmonics at mid and high frequencies ("creamier" sound).
These differences become more noticeable at higher volumes.
The EL84 and 6L6 tubes produce a big low-end thump and have a very good dynamic range. They offer a
more traditional "American Rock" sound. The EL84 and 6V6 tubes produce a creamy sound with nice dis-
tortion. 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 dis-
tort, 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 perform-
ance and longevity.
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 enve-
lope or bubble. The tube's longevity 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 produces 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 cru-
cial that they (if there is more than one) be replaced by a matched set. If you're on the road a lot, we rec-
ommend 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).
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V32H GUITAR AMPLIFIER HEAD
Important Information About Tubes and Tube Products (continued):
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 adjust-
ment 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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V32H GUITAR AMPLIFIER HEAD
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 con-
tribute 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 dis-
torted 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 incorrectly 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 voltages that are typically present in tube circuitry.
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V32H GUITAR AMPLIFIER HEAD
System Block Diagram:
12AX7A
12AX7A
12AX7A
V2A
12AX7A
V2B
CHANNEL
SELECT
GUITAR
INPUT
V1B
V1A
OVERDRIVE
GAIN
TREBLE MID BASS
BOOST PRESENCE
CLEAN
VOLUME
PHASE
SPLITTER
EL84
V4
EFFECTS EFFECTS
CHANNEL
SELECT
12AX7A
V3A
SEND
RETURN
EL84
V5
OVERDRIVE
LEVEL
12AX7A
V3B
8 OHM
SPEAKER
EL84
V6
EL84
V7
REVERB
DRIVE
REVERB
RECOVERY
REVERB
LEVEL
Declaration of Conformity
Manufacturer’s Name: SLM Electronics
Corporate Headquarters: 1901 Congressional Drive, St. Louis, Missouri 63146
Primary Production Facility: 700 Hwy 202 W, Yellville, Arkansas, 72687
Product Type: Audio Amplifier
Products meet the regulations for compliance marking under:
ETL standards UL6500, UL60065, or UL813
CSA standards E60065 or C22.2 No.1-M90
CE safety standard EN60065
CE EMC standards EN55103 or EN55013 and EN61000
FCC standards 47CFR 15.107 and 15.109 Class A
C-tick designation Level 2, ABN #56748810738, ARBN# N222
KETI standard K60065 (limited model approval)
Compliance Support Contact: SLM Electronics, Attn: R&D Compliance Engineer
1901 Congressional Drive, St Louis, Missouri, 63146 • Tel.: 314-569-0141, Fax: 314-569-0175
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V32H GUITAR AMPLIFIER HEAD
V32H TECHNICAL SPECIFICATIONS:
OUTPUT POWER RATING
SIGNAL TO NOISE RATIO
GAIN
30 Watts RMS @ 6 % THD, 8 ohm load, 120 VAC
71dB Typical
Clean 56dB, Overdrive 101dB
12dB range @ 6kHz
+10db @ 900Hz
TREBLE
BOOST
MID
10dB range @ 1kHz
8dB range @ 150Hz
+8dB @ 10kHz
BASS
PRESENCE
PREAMP TUBES
POWER AMP TUBES
POWER REQUIREMENTS
(3) 12AX7A
(4) EL84
120 VAC, 60 Hz, 35VA
100/115 VAC, 50/60 Hz, 35VA
230 VAC, 50/60 Hz, 35VA
21” W x 7-3/4” H x 8-1/8” D, 25.5 lbs.
SIZE AND WEIGHT
The V32H 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.
Specifications and information in this manual are subject to change without notice.
©2005 St. Louis Music, Inc • 1400 Ferguson Avenue • St. Louis, MO 63133
47-399-02 • 110405
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