Royer Labs R-121 - Manual (Page 6)

variety of preamps, and their limited frequency response characteristics make mic loading less
of a concern.
Ribbon microphones generate a highly accurate signal, but the average ribbon mic generates
approximately 20dB less output than condenser microphones. Remember, the ribbon transducer
does not have the benefit of a condenser mic’s built-in “head amp,” so a non-powered ribbon
microphone relies solely on the microphone preamp for all its gain!
The so-called ideal preamplifier is the proverbial “straight wire with gain.” This may be
considered the technological ideal and does not include coloration as a desirable feature.
However, coloration is often desirable and has given rise to the popularity of certain preamps and
even preamp stages in mixing desks. Neve preamps and the famous Trident A Range mixing
console are highly praised for their classic sound.
So what pre’s should we use with our beloved ribbon microphones?
The features that translate into top performance for a ribbon microphone are the following:
1. High gain. A ribbon microphone works best with preamplifiers that have at least 60-70dB of
clean gain.
2. Low noise is a must! With the amount of gain required for efficient operation of a ribbon
microphone, the noise characteristics of the preamp play a pivotal role in overall performance
of the captured acoustic event.
3. Load characteristics: A suitable preamplifier should have input characteristics that impose the
least amount of loading on the ribbon element. In other words, the input impedance should be
high enough that its effect on the performance of the mic is negligible. A good rule of thumb
is to have a preamplifier with input impedance at least five times the impedance of the
microphone.
For example, if the mic is rated at 300 Ohms (as the R-121 is), the preamp should have an
input impedance of at least 1500 Ohms. If the impedance of the preamp is too low, the
microphone will lose low end, body and sensitivity.
4. Transparency: A good preamp should sound natural, with no edginess. Tube preamps sound
warm, yet wonderfully transparent. Transformer coupled preamps sound punchy. When
recording with condenser or dynamic microphones, engineers often choose mic preamps that
help “warm up the mic,” but warming the signal up is not as important a consideration with
ribbon mics because they are by nature warm and realistic sounding. At this point personal
taste should prevail over anything else.
In conclusion, try to find the best preamp you can afford that has good gain characteristics
and low noise. Coloration is optional.
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