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The TOA E 131 is a single channel, 1/3 octave active graphic equalizer designed
to allow clean, accurate audio equalization for stage, studio, or commercial
applications.
The E 131 provides 12 dB of boost or cut at each of its 28 frequencies, which are
centered at ISO 1/3 octave increments from 31.5 Hz to 16 kHz. Its signal to noise
ratio is over 120 dB making the E 131 one of the quietest equalizers on the market.
The E 131's active bandpass/bandreject filters are designed for minimum phase
shift, and feature smooth slide controls with center detents for easy and accurate
adjustment. The filters are summed in parallel for reliability, so that the failure
of one filter does not interrupt operation of the others.
In addition, continuously variable high-pass filters are provided on the front
panel. The high-pass filter has a slope of 18 dB per octave and is variable from 15
Hz to 120 Hz, while the low-pass filter has a 12 dB per octave slope and is
variable from 8 kHz to 25 kHz.
An input level control on the E 131 gives 12 dB of adjustment to allow a wide
variety of input sources. An LED indicator illuminates when either the input or
the output comes within 6 dB of clipping. In addition to the usual EQ in/out
switch, an automatic EQ bypass function provides complete equalization
bypass in the event of loss of AC power, and an output muting function
suppresses turn-on/turn-off transients.
A smoked plastic security cover is included with the E 131 to guard against
accidental disturbance, or intentional tampering when used in fixed
installations.
Inputs and outputs are transformer-isolated and balanced, with both XLR and
1/4" stereo phone jacks. Ground lift switches are provided at both inputs and
outputs to reduce hum and prevent ground loops.
The E 131 can be mounted in a standard 19" rack and occupies 3-1/2" of vertical
space. The rugged front panel is made of 1/8" (3mm) cast aluminum, backed with
a 1/8" (3mm) steel liner for added durability.
1. 28 filters on ISO 1/3 octave center frequencies
from 31.5 Hz to 16 kHz.
2. 12 dB boost or cut at each center frequency,
continuously variable.
3. Signal to noise ratio greater than 120 dB.
4. High quality, low phase-shift active filters.
5. Precision calibrated, noiseless slide controls
with center detent.
6. Equalizer In/Out switch.
7. Continuously variable high- and low-pass
filters.
8. LED peak indicator to detect clipping at input
or output levels.
9. Variable input level control to accept variety
of input sources.
10. Automatic EQ bypass circuitry.
11. Transformer-isolated balanced inputs and
outputs with XLR connectors and phone
jacks.
12. Ground lift switches on input and output.
13. Smoked, plastic security cover is included.
14. Heavy aluminum die-cast front panel, stand-
ard 19" rack mountable.
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General Description
Features