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disconnect one of the microphone’s two Pin-1 ground connections. A better method is to
make a small ground lifter out of a male-female XLR barrel adapter. Switchcraft makes a
very nice one and it takes less than five minutes to wire it up. Simply connect Pin-2 to
Pin-2, Pin-3 to Pin-3, and leave Pin-1 disconnected. Correcting the problem at the
preamplifier would be preferable, but is often more difficult and/or expensive.
In conclusion, try to find the best preamp you can afford that has good gain
characteristics and low noise. Coloration is optional.
Equalization and Ribbon Microphones
One of the great strengths of ribbon microphones is how well they take EQ. Even with
substantial amounts of equalization, ribbons retain their natural, “real” quality. For
example, where a lead vocal is being performed on a ribbon microphone, you can actually
boost the upper end frequencies to the point where the ribbon mic emulates the
performance curve of a condenser mic with excellent results. This is not to say that a
ribbon microphone can replace a quality condenser mic, but the EQ friendliness inherent
in ribbon microphones does allow for an enormous amount of flexibility.
The reason that ribbon mics take EQ so well is because of their inherent low self-noise
(less than 15 dB) and unusually smooth response characteristics. Dialing in high amounts
of equalization on condenser or dynamic microphones also means dialing in extra amounts
of the microphones distortion products and self noise; garbage that contributes to an
unnatural, unpleasant sound. Because distortion and self-noise are almost non-existent in
ribbon microphones, high levels of EQ can be used without adding harshness or excessive
noise.
Hum Noise & Mic Orientation
All dynamic microphones, including ribbons, utilize powerful magnets in their motor
assemblies and matching transformers, and are, to some degree, susceptible to picking up
stray alternating magnetic fields. Power transformers (such as those found in guitar
amplifiers) and alternating current motors are the most likely sources of radiated noise.
Building wiring and electrical utility transformers are other likely sources. A well-
designed microphone provides shielding to minimize the effects of stray magnetic
radiation. In some cases complete isolation is impossible and the result is usually hum or
buzz. Ribbon microphones can potentially manifest this condition to a greater degree
because of their higher gain requirements. With vintage ribbon microphones that employ
large bulky magnet structures, the problem can be worse.
Royer SF-1 and SF-12 microphones are designed to minimize the effects of unwanted
radiation by integrating the transducer barrel as part of the magnetic return circuit. With
this design, the barrel housing the transducer serves to complete the North-South
magnetic return and neutralizes the effects of outside magnetic radiation. The SF-1 mono
and SF-12 stereo ribbon microphones go one step further by incorporating toroid
impedance matching transformers, which have a natural ability to repel magnetic radiation.
Dynamic and ribbon microphones are passive devices, meaning they incorporate no
external or internal power supplies and have no head amplifier and therefore cannot
