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Two independently voiced preamp channels,
that can be mixed together
An independent channel voicing topography is used on the Coyote amplifier for a high degree of voice versatility.
This design has several intelligent advantages. First, the
independently voiced preamp channels alleviate the need for tone controls
such as bass, midrange, treble or presence. By removing the tone
controls your amplifier is simpler to use and it becomes easier to find
great tones. In addition, mixing of the two voices provides a greater
degree of achievable gain. The gain is extracted from a total of four
triodes. Because there are four triode tube stages alone in the pre
amp, your guitar signal is rich with even order harmonics before it
even gets to the power tubes where it will pick up a massive amount of
additional tube tone. This design gives the user a greater degree of
complexity and responsiveness for a given instrument input signal.
Channel one is voiced for a thicker bass tone, while channel two is
voiced for a more focused bright tone. Each channel is controlled by
its own volume control. When one channel is set for its volume the
other channel can be added for the desired level of tone enrichment. |
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Cathode biased EL84 power amp
The Coyote has been designed with a classic cathode biased power amp design.
The power amp is rich in harmonic content and has a great British
character, which is developed via (2)-EL84 power tubes. The power
section is self biased allowing power tubes to be changed without the
technical attention normally required by amplifiers using grid biasing.
The simplicity of the Coyote design is truly an asset for the user. The Coyote's output transformer is equipped with both 8-ohm and 16-ohm speaker taps providing good flexibility for your speaker needs. |
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Mid-frequency cut switching
The Coyote amp has a natural midrange emphasis in its overall frequency response.
Engaging the midrange cut switch will tend to reduce the midrange level
of the amplifier's frequency response. The mid cut only affects the
bright channel, and when the midrange is in the "cut" setting the Coyote achieves
a greater degree of clean headroom. With this setting you can
achieve the same result as with a Top-Boost. If the mid switch is left
in
the "emphasis" setting, the amp will move into a more aggressive mode. |
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High and low sensitivity input jacks
By using the high and low sensitivity inputs the user can find a variety of dynamic range colors with the Coyote.
The low sensitivity input allows you to obtain a larger degree of clean
headroom, especially with lower output pickups. If the high sensitivity
input is used a greater degree of output tube overload can be achieved.
The drive signal from the high sensitivity input is two times greater
than that of the low sensitivity input.
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High Z power supply without the ghost-notes
Another classic design feature found on the Coyote is the high impedance power supply, which is found in almost all vintage amplifiers.
The high impedance power supply causes some variance in the amplifier's
current levels when demand is placed on the amp or when the amp is run
at full power. Typically a high impedance power supply will fluctuate
with the player's performance, which tends to give the amp a distinct
character. This phenomenon is readily found in tube rectified vintage
guitar amps. This is a feature that is considered desirable by most
players. The trade off is that this condition can cause the user to
hear a “Ghost note” on top of the fundamental note. While the Coyote was
designed with a high impedance power supply, it was also designed to
reduce the “Ghost note” effect to a level below detection, thus giving
the Coyote the best of both worlds.
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Coyote Front Panel
Giant Version |
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Coyote Rear Panel
Giant Version |
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Top quality components
Top quality electrical parts are just another feature that help make the Coyote an exceptional value. The Coyote shines inside and outside, as much as it shines sonically. |
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Non-magnetic Aluminum chassis
Quality starts from the ground up. The Coyote has been built on a thick folded Aluminum chassis. Each corner of the Coyote's
chassis has been welded for added strength and support. Building a
guitar amplifier on an Aluminum chassis has several key benefits. The
first of these benefits is that Aluminum exhibits a non-magnetic
behavior. Power transformers create magnetic fields, and because of its
inherent properties the Aluminum chassis will not interact with these
fields, thereby reducing 60Hz hum. In addition, Aluminum cannot rust
like steel and is many times lighter than steel.
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Hand built Terminal board electronics
Terminal boards are just another intelligent construction feature within the Coyote amp. Terminal board construction is extremely
reliable because of superior mechanical contact between the parts and
connecting wires. Mechanical strength is achieved when the leads from
the parts are fed directly into the turrets themselves and then
soldered for guaranteed electrical bonding. Terminal board construction
provides ease in changing circuitry as ongoing development occurs.
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Metal Film resistors
are used rather than the typical carbon composition or carbon film type
resistors. Metal film resistors can be obtained in precise values and
also boast greater temperature coefficient ratings, which in turn make
the part very stable and less likely to drift from its original value.
Each resistor found within the Coyote amplifier
has been specified and designed to have a greater power rating than the
circuit actually demands. This will ensure longevity of the part and
proper circuit operation for the life of the amplifier. Metal film
resistors are also superior with regard to noise, unlike their carbon
composition counterparts. Carbon composition resistors are typically
very noisy, giving rise to an increased hiss when the amp is on. Metal
film resistors, on the other hand, are extremely quiet. This factor
proves to be very desirable, especially when recording.
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| Custom made 1% tolerance capacitors are utilized throughout the Coyote amplifier, which provides for sonic consistency from one amplifier to the next. The capacitors used within the Coyote amplifier are of the high-grade film and foil polypropylene and silver mica varieties. |
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Ceramic Tube sockets are also a part of the Coyote's
high grade component makeup. Ceramic sockets do not burn and are less
likely to arc with the high voltage present at the tube pins. Lower
grade tube sockets such as phenolic or plastic can burn and cause a
carbon resistance to form, which in turn will increase arcing between
the high voltage tube pins.
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Hand tested select matched preamp and power tubes. Mojave AmpWorks tests all of the tubes it uses in every Coyote.
This step will ensure that each amp has minimum hum and a balanced
gain. Balanced pre amp and power tubes provide the amplifier with
improved clean headroom and smooth overload tones that move fluidly
from one sound to the other. This step requires the personalized
attention that is synonymous with the entire construction process
involved with the Coyote.
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The Coyote amplifier has been completely hand-wired with Teflon insulated silver-plated copper wire.
Teflon insulated wire will not burn like plastic coated wire. Teflon
insulated wiring also resists heat, preventing cracking of the wiring
insulation. In addition, silver-plated copper wire is an excellent
conductor.
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Creating a Better Guitar Amplifier
The first way to improve any design is to learn from the past. Mojave AmpWorks has
the distinction of having a great deal of experience in the restoration
and service of vintage guitar amps. A large part of our experience has
been gained solving problems with older guitar amps that had many miles
on them. All amps start out new and wind up old. It comes down to how
they weather the wear and tear. |
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Fluid chassis layout for quick easy circuit assessment
One of the most distinctive features of the Coyote amplifier is the exquisitely laid out circuitry. Unlike other amplifier layout schemes, the Coyote
amplifier utilizes a fluid and simplistic parts layout system that
provides even the non-technician with an easy way to understand their
amplifier. Mojave AmpWorks
felt it was important to keep the amp as easy to understand on the
inside as it is to use on the outside. Looking at the adjacent image,
one can see there are clean and accessible solder connections for each
part, as they are placed onto dedicated turret pairs across the turret
board. |
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Central point electrical grounding
Central point grounding is favored for its lower noise and its increased grounding facilitation.
Central point grounding reduces ground loops while also improving
conductive points for each area requiring ground connection. Power amps
are better served when grounds are brought together to their respective
points and not just made in different points across the chassis. |
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A detachable AC receptacle with built in fuse holder is a good start.
Most amps built today have a detachable AC cord as opposed to the AC
power cord being permanently attached to the chassis. By using a
detachable AC power cord, it can easily be replaced in the event that
it becomes cut, frayed or damaged. This is a lot less hassle than
having to change a power cord that is permanently attached to the
chassis. |
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A built in fuse holder that also contains a spare fuse has it’s advantages. The
main benefit of having the fuse holder built into the AC receptacle is
that there is no fuse holder protruding from the chassis back panel.
Items such as fuse holders that protrude from the back of the chassis
are subject to breakage in the event there is an impact along the back
panel of the amp. A broken fuse holder or missing fuse cap will render
the amp useless. This is an all to common problem among both vintage
and modern amps which use that design. Mojave AmpWorks amplifiers
have the fuse holder safely packaged within the confines of the AC
socket. An added bonus is the convenient spare fuse that is stowed
inside the fuse holder itself. |
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Speaker connection is easy and dependable. One problem encountered by guitar players is knowing what settings to use when running more than one speaker cabinet. Mojave AmpWorks amplifiers
have clearly marked back panels making it easy to understand and use.
There are no “Impedance Selectors” on the Mojave AmpWorks amplifier.
Impedance selectors are switches or contact plugs that wear out over
time. This creates an opportunity for noise and intermittent operation
due to poor contacts within the switch or plug. Mojave AmpWorks amplifiers are trouble free and easier to use without these switches. As a result, Mojave AmpWorks amplifiers are also more dependable. |
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Well Grounded input jacks prevent your amp from becoming a radio receiver!
The most common cause for radio frequency amplification by a guitar
amplifier is poor grounding on the input jacks. Amplifiers that are
designed around a mechanical ground from the input jack to the chassis
have an open door for this problem. If the contact between the input
jack and chassis corrodes the ground is poor and you will become an
antenna when you plug your guitar cord into the amp. To prevent this
action, the Mojave AmpWorks amplifier
has no mechanical ground made at the input jack, rather there is a
solid ground made with a soldered connection directly to the input jack. |
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Dual-Primary Power Transformers.
The Coyote is built with a High Efficiency Dual-Primary power
transformer. This means higher efficiency and cooler
core temperatures. The result is a more reliable power supply with
better current capacity. The Coyote is also designed with a larger
power supply filtering system resulting in better clean headroom and
dynamics. Upgrades like these are all part of the improvements built on
classic designs. Power
transformers are built with low profile lugs rather then bulky wires
sprouting out from the transformer making the amp cleaner and neater on
the inside. | |
