PRE420 Instruction Manual – rev. E
Page 5
dimensional shield surrounding the
microphone-level signal traces to block RF
interference. Also, the microphone-level
traces are arranged in a star-quad layout to
prevent magnetic interference. Benchmark's
innovative shielding and filtering techniques
have given Benchmark microphone-preamps
a proven track record for exceptional
performance in difficult, RF-intensive
locations.
This RF-immunity is coupled with ultra-low
distortion performance at high-frequencies,
beyond that of most mic-preamps, giving
your audio remarkable realism. With an
amazingly low THD+N of 0.00024% (see
specs), we encourage you to compare the
PRE420's performance specifications and
sonic performance with any other mic-
preamp.
Microphone pre-amplifier circuits usually
suffer from non-linear performance at ultra-
sonic frequencies. This non-linearity causes
inter-modulation distortion (IMD) components
that fold down to audible frequencies. Unlike
harmonic distortion (THD), IMD produces
distortion tones that are very un-natural and
non-musical. IMD also masks and alters the
subtle details of delicate high-frequency
transients such as those produced by bells.
Benchmark MPS series preamps have always
had outstanding high-frequency performance
as well as freedom from IMD. The PRE420
takes the Benchmark design one step further,
and achieves the lowest IMD that we have
ever measured in a microphone preamplifier.
We believe that you will enjoy the sonic
performance and features of the PRE420.
