Royer Labs SF-2 - Manual (Page 7)

A good preamplifier should sound natural, with no sign of edginess or excessive noise. Vacuum
tube preamplifiers sound warm, yet airy and transparent. Do not expect a vacuum tube
preamplifier to be as quiet as a solid-state preamp, as electron emissions from tubes tend to
convey more thermal noise than transistors. Tube preamplifier noise is far less of an issue with
the SF-2 than with conventional ribbon microphones because the SF-2’s high output allows for
preamp gain to be set lower, reducing preamp generated noise. Transformer coupled designs tend
to sound punchy and full bodied and offer the added benefit of true electronic isolation. This
greatly enhances their ability to interface with other equipment with minimal noise or hum.
There are many excellent preamplifiers on the market today. Choose one that fits your budget and
offers good performance, remembering that you get what you pay for. If you have the
opportunity to audition one or more preamplifiers before you buy, do so. Microphones and
preamplifiers work together as a team and some are better matches than others.
The SF-2 is capable of substantial output signal, especially when used for high SPL applications
like drum overheads. It will not overload or produce distortion up to its SPL handling capacity of
130 dB SPL. In actuality, the SF-2’s ribbon would stretch before its electronics would overload.
Due to the high output potential of the SF-2 on loud sound sources, it is recommended that the
pad on the microphone preamplifier be engaged to prevent the possibility of overloading the
preamplifier’s input stage electronics. Some preamplifiers are more thoughtfully designed than
others, with a suitable pad that is placed before the preamp’s active electronics. Other pre’s may
have a pad incorporated into a “feedback loop”, which could still produce distortion due to
overloading even when the pad is engaged. Although this is not often an issue, we felt it was
important to cover the subject.
In conclusion, preamplifier coloration is optional and a matter of personal taste. Some people like
and use the effect of coloration while others strive for absolute transparency.
Equalization and Ribbon Microphones
One of the great strengths of ribbon microphones is how well they respond to EQ. Even with
substantial amounts of equalization, ribbons retain their natural sound quality. For example, if a
lead vocal is being performed on a ribbon microphone and you want more highs, you can boost
upper 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 always
replace a quality condenser mic, but the EQ friendliness inherent in ribbon microphones does
allow for an enormous amount of flexibility.
Ribbon mics take EQ well because of their inherent low self-noise and unusually smooth
frequency response characteristics. Dialing in high amounts of equalization on condenser or
dynamic microphones also means dialing in equivalent amounts of the microphone’s distortion
products and self noise; musically unrelated artifacts 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.
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