Carr Hammerhead MK II User manual

CARR AMPLIFIERS
OWNER’S MANUAL
Revised 26 Feb 2010

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Hammerhead Mk II Instructions
Thank you for purchasing a Carr Hammerhead Mk II amplifier. The Hammerhead Mk II
employs a pure and simple circuit keeping tone and gain modifiers (Impact and Grip) out of
the direct signal path. The Tone control can be switched in or out of the signal path for
added flexibility. Tones from clean with grit to very heavy output tube overdrive are easily
dialed in using our unique controls. The Hammerhead Mk II has roots in 50s and 60s
eclectic American and British amplifiers combined with superior construction and modern
cutting edge components. Give yourself time to experiment with the 5 controls. You will
find the Hammerhead Mk II covers a surprising amount of sonic ground.
Volume – Controls the drive of the amplifier. Settings below 11 o’clock will yield different
shades of clean tones while higher settings will bring the amp to overdrive (for the average
output pickup).
Impact – Using a parallel circuit the 4 position Impact allows you to select from
1) flat response
2) high treble emphasis like a ‘blackface’ style amp
3) high treble and upper midrange emphasis like a metal face early 70s British amp
4) high treble and full midrange emphasis like a late 60s British style amp
The Impact control is interactive with the Volume control and will have maximum effect
when the Volume is at 3 o’clock and below.
Master – Controls how much of the preamp signal gets to the power tubes. Typically a
setting of 10 o’clock or higher yields the best tone. You will get more output tube overdrive
and bass response at higher Master settings.
We recommend starting with the Master set very high and then bringing up the Volume to
set overall loudness (see Recommended Settings). From this point, you can roll down the
Master and/or roll up the Volume to find the perfect combination of volume, drive, and tone.
Grip – This 4 position switch increases preamp gain and drive from position 1 to 3.
Position 4 maintains the gain level of position 3 while adding more focused response to the
leading edge of notes.
Tone –When you turn the Tone control clockwise you will feel a click as it activates. The
Tone control starts in the bass position. Turning the control further clockwise will allow
more high frequencies through. The Tone control works by rolling off the high end and is
similar to a variable cut switch. You will find that having the Tone set at 12 o’clock gives
the closest approximation of a ‘blackface’ type of sound. For maximum gain, switch the
Tone control to the OFF position.

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Standby – Set amp to standby (switch baton down) before turning on the power switch (see
On-Off-On below). After 1 minute of warm up, switch the Standby baton up. The amp is
ready to be played. Using the Standby switch every time the amp is turned on will prolong
tube life.
On – Off – On – Selects between two ON positions and the OFF position (middle). The
two ON’s are wired in opposite phase of each other. If you receive a shock from another
piece of equipment (a microphone or another amp) that is not properly grounded, or if you
hear static, switching to the opposite ON may solve the problem. This is sometimes called
“switching polarity”.
Bottom Panel
Fuse –In the unlikely event that a tube fails, the amp is protected by a 1.5 Amp slow blow
fuse for 120v and 100v (North America and Japan) models, or a 0.75 Amp slow blow fuse
for 220v and 240v (Europe and Asia) models. Please consult us or a qualified tech for
further instruction or assistance in the event of a fuse blowing. The fuse is located on the
bottom of the chassis by the power cord.
Speaker output jack – The speaker output jack is located between the power and the
preamp tubes on the bottom of the chassis (see Chassis Diagram). The Hammerhead Mk II
is designed to drive an 8 ohm load. Maximum power and tone will be realized when
connected to an 8 ohm speaker or cabinet. The speakers in Hammerhead combos and
extension cabinets are configured to provide the amplifier with an 8 ohm load.
The Hammerhead will work with a 16 or 4 ohm cabinet with the following caveat - you will
lose a little power from the impedance mismatch, and the power tubes will have to work a
bit harder and thus age faster.
To run an external cabinet, turn the Hammerhead OFF, unplug the internal speaker (combo
amps) and plug in the external cabinet’s speaker cord. Alternatively, a “Y” speaker cord can
be used to run an 8 ohm external cabinet along with the internal speaker(s) of a combo amp
without damage to the amp (the total impedance or speaker load in this case will be 4 ohms
– see the previous paragraph).
Damage will result from operating the Hammerhead without a speaker load.

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Biasing your Hammerhead Mk II
The Hammerhead Mk II is a cathode bias (self bias) amp and as such does not require a bias
adjustment when changing tubes. Please use well-matched pairs of output tubes for
maximum performance. The Hammerhead can only use matched pairs of EL-34, KT77,
KT88, or 6550 power tubes.
Carr Amplifiers selects and tests the finest current production tubes specifically for each
amplifier model. Caution should be used when buying replacement tubes from any dealer
who does not have a return policy as all tubes can have problems (NOS tubes are
susceptible to microphonics and failure too).

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Recommended Settings
Humbucker
Pickup Sound Volume Impact Master Grip Tone
Bridge Dark TX Tone Off
Bridge Rock Off
Bridge Australia Off
Bridge Jangle Crunch
Both Groove
Neck Blues Off
Single Coil
Pickup Sound Volume Impact Master Grip Tone
Bridge Bark Off
Bridge Driven Clean Off
Bridge Rock Off
Bridge Rockin’
Apartment
Neck Blues
Neck Tough Jazz

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Important Reminders
Please keep the original packing materials in case your amp
needs to be shipped for service.
When inserting power
tubes, the power tube key
must line up with the tube
socket keyway.
Do not insert power tubes
with missing or damaged
keys or pins.
When inserting preamp
tubes, the tube pins must
line up with the tube socket
holes.
Do not insert preamp tubes
with missing or damaged
pins.
To reduce the risk of electric shock, keep the unit away from
excess moisture.
No user serviceable parts inside.
Potentially lethal voltage present.

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CARR AMPLIFIERS WARRANTY
All Carr amplifiers are warranted to be free from defects in workmanship (solder
joints, hardware assembly etc.) for the lifetime of the original owner, and free from
defects in materials (including cabinet) for three years from the date of purchase by the
original owner, provided that:
The owner mails the signed warranty registration card (next page) and a copy of the
original sales receipt to Carr Amplifiers within thirty days of purchase.
Problems are not the result of misuse, abuse, tampering, circuit modification, improper
tube installation (incorrect orientation of tubes can damage the amp), or spilled
beverages, as these will void the warranty.
The amplifier is shipped to Carr Amplifiers in the original packing materials with freight
paid by the purchaser. We pay the return shipping after the warranty work is complete.
Tubes, speaker(s), and reverb tanks carry a ninety-day warranty, and are subject to
the same terms and conditions as above.
Please call us at 919-545-0747 if you have a warranty claim. Be prepared to provide the
model and serial number of your amp. We will issue a Return Merchandise Authorization
number (RMA#) before the amplifier is shipped for service.
For customers outside of North America, warranty and repair service is provided through
the dealer where the amp was purchased.
Shipping address:
Carr Amplifiers
23 Rectory St., Suite E
Pittsboro, NC 27312
Mailing address:
Carr Amplifiers
433 W. Salisbury St.
Pittsboro, NC 27312
Tel: [phone]
Fax: [phone]
www.carramps.com
[e-mail]

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