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 a higher 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
foot traffic, or suspended in an unsafe manner. Make sure that the microphone stand is secure and
not likely to fall.
If you have any questions or concerns about operation of your MA-37 please contact the factory:
