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4079 Equalising Amplifier
4088 Limiter / Compressor
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4079 Equalising
Amplifier
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This board
provides 20dB of lift and cut
at Bass (150Hz) and Treble
(4.5kHz) frequencies. Controls
may, if required, be fitted
directly on the pcb
(Electrospeed sell suitable
PCB mount lin controls).
An auxiliary output is
provided from the first stage
(pre-eq) for by-pass or other
purposes.
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| Stock no. 01-145 |
4079 Price: |
£25 |
| Technical
Specifications |
| · |
Dimensions |
25 x 112 x 15 mm |
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Supply |
+/- 12v DC @ 20mA |
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Response |
25Hz - 20kHz +/- 0.5dB
(controls centred)
Bass Mid = 150Hz Treble Mid =
4.5kHz
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4088
Limiter / Compressor |
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The
4088 is a general purpose
compressor card, featuring true
RMS signal detection within the
control loop and eight
selectable compression slopes,
from 1.27:1 to 10:1. Another
useful feature is that at 6dB of
compression the input and output
levels remain constant, which
means that the compression slope
can be changed without the
necessity to re-adjust gains.
(see fig.)
The compression slope can either
be selected by the DIL switch on
the card or via a 16 way DIL
header and front panel switch. |
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There is an
on-board LED to indicate the
onset of compression with
provision to connect an
external LED if required with
no necessity for any change to
the 4088 pcb.
The threshold can be set by
VR2 on the PCB to allow for
input levels of between +10
and -10 dbm, for 6dB of
compression. The other pre-set
(VR1) is factory set to
minimise the VCA distortion.
Another useful addition is a
separate VCA control pin,
(4b), to enable the 4088 to be
used as a VCA card with
external control. This require
approx. -30mv/dB of
attenuation.
Because of the RMS rectifier
characteristic of the control
loop, independent adjustment
of attack and release times is
not possible. The capacitor C6
can be changed to accommodate
different attack/release times
if desired. This is approx.
127dB/sec. The release rate
can be calculated for other
values of C6 by using the
formula 1267/C(uF) dB/sec,
where C is the value of C6.
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| Stock no.
01-150 |
4088
Price: |
£75 |
| Technical
Specifications |
| · |
Dimensions |
67 x 114 x 15 mm |
| · |
Supply |
+/- 12v to +/- 15v DC @
30mA |
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