Mojave MA-37 User manual

MA-37 Multi-pattern Vac uu m Tube
Condenser Microphone
Please visit www.mojaveaudio.com for more information including:
• Recording Tips
•FAQ’s
• Warranty Registration
• Customer Service
CONTENTS
CONTENTS 1
INTRODUCTION 2
UNPACKING AND INSPECTION 2
GENERAL INFORMATION 3
SAFETY INSTRUCTIONS 3
OPERATION 4
CARE OF YOUR MICROPHONE 5
TECHNICAL SPECIFICATIONS 6
POLAR RESPONSE 7
POLAR PATTERN SELECTOR 8
BASS CUT SWITCH 8
WARRANTY 9

INTRODUCTION
Congratulations on your purchase of a Mojave Audio MA-37 Multi-pattern Vacuum Tube
Condenser Microphone. Your MA-37 was carefully designed and constructed using only the
finest materials. The MA-37 microphone is capable of delivering superb performance and,
with minimal care, will do so for many years. Your MA-37 was thoroughly tested and given a
24-hour factory burn in prior to shipment.
The MA-37’s capacitor capsule and electronics are adapted from mid-1950’s design practice. The
MA-37 utilizes a European-made EF-86 vacuum tube and a Lundahl audio output transformer
wound to our specifications. By utilizing modern components, the microphone system emulates
the performance of “classic” tube microphones without using esoteric, unreliable, or hard to find
components.
The MA-37 is guaranteed to perform as specified and is suitable for recording even the most
demanding music, provided that the microphone is used sensibly.
For optimum performance from your microphone, please read this manual thoroughly and
familiarize yourself with the proper use of the MA-37.
UNPACKING AND INSPECTION
Carefully unpack your MA-37 and verify that all of the accessories included with the
microphone are accounted for. Do not discard any packing materials! If anything is missing or
damaged, contact your dealer or Mojave Audio immediately.
Items included with the MA-37 are:
1. MA-37 microphone inside a pelican-style carrying case.
2. AC operated microphone power supply.
3. 20-foot premium microphone cable with 5-pin male and female connectors.
4. AC power cable for power supply - molded IEC business machine type with plug.
5. Rugged carrying case for all above items.
Verify that the serial number of your MA-37 matches correctly with the one on your receipt. The
MA-37 serial number can be found on the silver ring found just above the base. When
corresponding with Mojave Audio about your microphone or when service is required, we will
need to know the serial number, so keep it handy.

GENERAL INFORMATION
The MA-37 is a multi-pattern vacuum tube microphone and requires a dedicated power supply
and 5-pin cable set for operation. These items are provided with the microphone. The capsule is a
6-micron, single-membrane gold-sputtered type. The vacuum tube head-amplifier delivers wide
bandwidth and low noise operation. The MA-37 utilizes a sub-miniature vacuum tube, which
necessitates the need for a dedicated power supply. The vacuum tube is premium grade EF-86
and will deliver excellent performance for many years. A specially designed, high-quality,
custom wound Lundahl audio output transformer delivers an isolated, truly balanced output
signal, minimizing the possibility of unwanted noise entering the preamplifier. As with all
vacuum tube microphones, a warm-up period is advised for optimum performance; usually about
ten minutes. The MA-37 includes a selectable bass cut switch.
SAFETY INSTRUCTIONS
WARNING!
To avoid electrical shock to yourself and damage to the MA-37, use proper circuit protection.
MA-37s purchased in the USA are set for 120V, 60 Hz operation. MA-37s purchased outside of
the USA are set for the voltages of the country to which they are exported. This information is
duly noted on the outside of the shipping box as well as on voltage selector of the power supply.
The MA-37 uses a line fuse for protection. Never replace this fuse with one of ahigher current
rating. Use only that type which was supplied with the unit. The power supply cord that is
supplied with your MA-37 is a standard “business machine” type. It is a good practice to
examine the power cord regularly. Never use a cord that shows damage or that has exposed
wires.
Other than the EF-86 tube, there are no user serviceable components inside the MA-37
microphone or its power supply. Always refer service to a qualified technician equipped to
service this equipment. Never expose the MA-37 microphone, its power supply or cable set to
water or any environment that may create an electrical hazard. In the event of a malfunction,
disconnect the MA-37 immediately and determine the nature of the malfunction before
attempting to use it again.
To avoid tripping over the microphone cable, make certain that the cable is not in the way of
foottraffic, or suspended in an unsafe manner. Make sure that the microphone stand is secure and
notlikely to fall.
If you have any questions or concerns about operation of your MA-37 please contact the factory:
[email protected]

OPERATION
When plugging the microphone in, the 5-pin XLR connectors between the microphone and the
power supply should be inserted gently into their corresponding sockets. Rough handling,
misaligned orientation, or trying to force the connections together too quickly could result
inbent pins.
Operation Tip!
Your MA-37 was thoroughly checked and burned-in before leaving the factory. Before using it
for the first time, we recommend connecting the MA-37 to its power supply and letting it warmup
for at least thirty minutes. Moisture build-up on the capsule or on the other high-impedance
components within the microphone can cause random noise or static. The thirty-minute initial
warm-up will drive out any residual moisture that may have collected on the internal
componentsduring shipping or storage.
Also note that if the MA-37 is being used with phantom powered microphones in a multiple
microphone setup, phantom power may be applied to the channel connected to the MA-37
without ill effect, provided that your standard 3-pin microphone cables are wired properly.
A grounded power cord is used to connect the power supply to an electrical socket. MA-37
power supplies are shipped pre-wired for standard AC voltage in the country where the
microphone is sold. If there is a need to change AC voltage (travel, sale to another country, etc.),
an external switch allows the power supply to be configured for 100, 115 or 230 volts at either
50or 60 Hz. Make sure the fuse is the proper value - 500 mA for 100-120 Volts AC and 250 mA
for230 Volts AC.
"Hot plugging" any vacuum tube microphone can damage the microphone’s electronics, so
always be sure to connect the microphone to the power supply with its multi-conductor cable
before connecting to AC power and turning the power supply on.
AC LINE FUSE
A spare fuse is included with your MA-37 power supply. It is located in the fuse carrier just
above the AC receptacle. To access the fuse, gently pry out the carrier with a flat bladed
screwdriver. The fuse is mounted in the clip and the spare is located is a small channel behind
thecover. Replace the fuse with the same type as supplied with your microphone.
MAINS VOLTAGE FUSE TYPE
100 Vo l t s AC T500mAL
120 Vo l t s AC T500mAL
220 Vo l t s AC T250mAL
In the rare event that you experience fuse failure, identify the cause of the failure before
using the microphone again! The most common cause for a fuse to fail would be a damaged
microphone cable or a broken or bent pin on a connector. The next most likely cause for fuse
failure is operation of the power supply on incorrect voltage.

CARE OF YOUR MICROPHONE
Your microphone is a delicate precision instrument, and it should be treated as such. Here are
some commonsense rules to keep your microphone healthy.
1. Be careful in your setup so that the microphone and/or power supply never falls to the floor.
Never suspend the microphone by its cable and be sure to position the cable so that it cannot
be tripped over. Falls to the floor have been the ruin of many a microphone.
2. NEVER hot plug the microphone (i.e. plug the microphone into an energized power
supply),as the resulting voltage surges can damage the microphone’s or following
preamplifier's electronics.
3. Keep the microphone, cable and power supply in a safe place, such as its carrying case or
amicrophone locker, when not in use.
4. When plugging in the 5-pin cable between the microphone and power supply, orient theplug
correctly and plug the connectors in gently. Rough handling or hurry-up plug-ins can result
in bent or broken pins.
5. Never connect the power supply to an AC power outlet that has different voltage than
whatthe power supply is set for.
6. Do not expose the microphone to dusty, smokey, or humid environments.
7. Any repairs must be performed by a qualified technician. Other than the EF-86 tube, there
are no user serviceable partsin the MA-37. For tube replacement instructions, please contact
us: [email protected]
8. Use a soft, lint free cloth to remove fingerprints and other blemishes on the microphone
body.Never use chemicals, solvents, or detergents.

TECHNICAL SPECIFICATIONS
TRANSDUCER TYPE: Externally polarized, pressure gradient
capacitor, single membrane
DIAPHRAGM: 1-inch diameter, gold sputtered
DIAPHRAGM THICKNESS: 6-micron
POLAR PATTERN: Choice of cardioid or omni; via mechanical shutter
FREQUENCY RESPONSE: 30 to 18,000 Hz. ±3 dB ("M" setting)
SENSITIVITY: -46 dBv referred to 1 volt per pa.
MAXIMUM SPL:
DISTORTION: Not to exceed .5 percent at 134 dB
SELF NOISE: Better than 18 dB
BASS CUT: M flat, V1 -6dB at 50 Hz., V2 -6dB at 100 Hz.
IMPEDANCE: 170 ohms, floating. Recommended load 1500 ohms or
higher
DIMENSIONS AND WEIGHT: Microphone – 6”x2” 1lb.
Power Supply – 9.5”x7.25”x4.5” 5.5lb,
Case – 18.5’x13.5”x7” 16lbs.
POWER REQUIREMENTS: 115 or 230 VAC, 50 or 60 hertz; 5 watts.
6 volts DC at 200 mA.
140 volts DC at 1.5 mA. from dedicated power supply
.

POLAR RESPONSE
Type: Multi-pattern
POLAR PATTERN
FREQUENCY RESPONSE

POLAR PATTERN SELECTOR
The MA-37 features a unique mechanical approach, developed by RCA in the 1930s and adapted
by Sony, to achieving a choice between cardioid and omnidirectional polar patterns – an adjustable
tuned acoustic chamber. To change the pattern selection from cardioid (C) to omni (O), insert a
small flat-head screwdriver into the slot and rotate clockwise approximately 90 degrees. It is
perfectly acceptable to stop anywhere between C and O in order to achieve a hyper-cardioid polar
pattern.
BASS CUT SWITCH
The bass cut switch, also known as a hi-pass filter, is located on the power supply, offering three
options: at (M), 100Hz (V1) and 200Hz (V2). As the MA-37 has an extended low frequency
response, the bass cut is useful in cleaning up the bottom end. V1 is useful for instruments such
as acoustic guitar. V2 is useful for instruments such as a tambourine or shaker. Either V1 or V2
can be useful for recording vocals, depending on the voice and desired result.

WARRANTY
Your Mojave Audio product is warranted to the original owner for a period of two years. Mojave
Audio guarantees this product to be free from electrical and mechanical defects and will repair
or replace defective components or replace the microphone at Mojave Audio's option. Should
service be required for your Mojave Audio product, please contact [email protected].
Excellent service will also be provided for products beyond the warranty period at a modest cost
for parts and labor.
Please visit mojaveaudio.com for the latest updates and technical information.
MODEL NUMBER
SERIAL NUMBER
DATE OF PURCHASE
PURCHASED FROM________________
1118 Chestnut St. Unit 104 • Burbank, CA 91506 • tel. [phone]
www.mojaveaudio.com
[email protected]