dbx 165 - Page 2

Dear dbx customer:
Your new model 165A is identical to the old model 165 except
for a
special
feature
called
PeakStop*
Until
a new manual is
produced, this
memo has all of the
necessary
PeakStop
information and is intended to
supplement the accompanying
165 manual*
The PeakStop feature allows you to
control the maximum peak levels at
the output of the 165A
irrespective
of
any other control* PeakStop comes
after
the compression
and other circuitry, including the output gain, so
it lets an
absolute
limit
be put on the peak-to-peak excursions of the
output* PeakStop works instantaneously; you are
able
to apply
moderate
amounts of dbx*s Over Easy compression and will
still be protected
from
large
transients, other short-term overloads, and
overmodulation*
Technically, PeakStop consists of a sophisticated
voltage-controlled
clipper that produces
a
minimum
of
audible distortion*
It
rounds the
corners
of
a peak rather than
cutting it off
sharply, as the word
''clipping'* usually implies*
By
making
a
signal's leading and trailing
edges
curved instead
of
sharp corners,
it reduces
the
amount of
higher
odd-order, offensive-sounding harmonics that conventional clipping
causes* The level
at
which PeakStop
is
activated is adjustable from
-2
to
424
dBm* Note
that
small signal
excursions above the set value
of
PeakStop are possible, to allow the rounding to
take
place;
therefore,
for
any
applications where you must not exceed a
given
ceiling, set
the
PeakStop control
1-2
dB below it to be sure*
The red PeakStop
LED
flashes whenever
peaks attempt
to
exceed PeakStop
level
and
get
reduced in amplitude*
To
disable the PeakStop function
altogether, simply set the control to 424 dBm (which is the maximum
output
level
of
the 165A anyway)*
In
use,
the
PeakStop
function can prevent an amplifier from being
driven
into
hard clipping, where
it
can lose control over the speaker
system* PeakStop
is
a
smooth, well-controlled clipper whose behavior
is
sonically similar to the gentleness
of
Over
Easy
compression;
its clipping
is much preferable to a power
amp's*
As
mentioned,
control
of
speaker
overexcursion, broadcast overmodulation,
and harsh
electronics
clipping
are all applications of
PeakStop* With
it and
Over Easy, you have the
best of both worlds:
virtually inaudible
rms
compression
and peak
protection downstream at the end*
sincerely,
dbx
Inc*
Professional Products
dbx Incorporated /71
Chapel Street
/
Box
100C/
Newton, Massachusetts 02196
/
Tel.
[6l7)-964-3210
/
Telex
92-2522