User guide

Fredenstein F600A Compressor
Installation:
Please power down your rack or box first, before inserting the F600A. Since the F600A uses the
link interconnect in the box or rack, it cannot coexist with any other third-party modules using the
same link interconnect (PIN 6 on the edge connector). If your are using a Fredenstein Bento box,
please turn off the the compressor link switches to any third party module(s), only turn the link
switches on between F600/F600A modules.
Other third party equipment not using the link interconnect, such as most Mic-Pres and EQs etc,
can be used simultaneously with the F600 in any enclosure. The power requirements are maximum
+/-16V, +/-200mA. Please make sure, in case you don't use a Fredenstein Bento, that your box or
rack can support the current. Please consult your third party documentation in case of any doubt.
To understand the function of the F600A, let's discuss first some terms:
Hard-Knee characteristics means the compressor will evenly compress all signal above the
Threshold as set by the Compression Ratio control. Soft-Knee means that the compressor will start
softly when the Threshold is almost reached with a reduced Compression Ratio. Then it will
increase the Compression Ratio until the Gain Reduction reaches 3 dB and the full Compression
Ratio is applied.
RMS (Root-Mean-Square) level detection measures the power (energy) of an audio signal, this
means in audio the loudness. Setting the compressor Side-Chain input to RMS, will result in a
more constant volume of the signal, but will allow short peaks to go through without compression.
The traditional Peak level detection measures the highest signal independent of its energy. This will
prevent short peaks to go through and overload the connected equipment such as Tape-Recorders or
A/D-Converters.
User Controls:
Gain Control:
Make-up gain can be applied in the range of 0 to + 15.5dB to compensate for the gain reduction.
Threshold Control:
Determines the input level at which the compressor is activated.
Attack Control:
Determines how fast the compressor reacts to signals above threshold.
Release Control:
If the signal drops below threshold, the release time determines how fast the compressor falls back
to 0 dB gain reduction.
Compression Ratio:
The amount of increase in output level relatively to the input signal. Minimum is 1.5:1, maximum is
100:1 (limiting)
Fredenstein F600A Manual V1.2 July 18, 2014 Page 2