TOA E-232 L Specifications

TOA PROFESSIONAL SOUND SYSTEM

2/3 OCTAVE GRAPHIC EQUALIZER

E-232

DESCRIPTION

The TOA E-232 is a dual-channel 14-band, 2/3-octave
equalizer, designed to provide clean and accurate audio
equalization for permanent installations. The E-232

provides 6dB or 12dB of boost or cut at each of its 14

frequencies, all of which are centered at ISO 2/3-octave

increments from 40Hz to 16kHz. The E-232 comes with
active bandpass/bandreject filters that are designed for
minimum phase shift. Slide controls feature a

precision-calibrated linear scale, noiseless operation, and
center detents for easy and accurate adjustment. Filters
are summed in parallel for reliability, so that the failure of
one filter does not interrupt operation of the others.

A unique feature of the E-232 is the ability to set the boost
range and the cut range independently on each channel.
A switch for each channel selects 6dB or 12dB for the
boost and another for the cut. For example, ranges of 6dB
boost and 12dB cut can be set on one channel and 12dB
boost and 6dB cut on the other. The 6dB positions spread
the adjustment over the full boost or cut portion of the
sliders’ travel. This, along with the calibrated linear scale,
allows precise, repeatable adjustments to fractions of a dB
in spite of the unit’s one rack size. This feature also allows
accurate matching of the equalization between the left/right
channels in stereo program systems.

A continuously variable highpass filter offers an
exceptionally wide control range. The highpass filter has a
slope of 12dB per octave and is variable from 15Hz to
300Hz. An EQ In/Out switch and an automatic EQ bypass
function (in the event of an AC power loss) provide a
complete signal bypass of the unit. An output muting circuit
suppresses turn-on/turn-off transients.

The input level control has a ±12dB adjustment range, to
allow for a wide variety of input levels/sources. An LED
indicator monitors both input and output levels and
illuminates when either comes within 3dB of clipping. The
inputs and outputs are unbalanced and utilize terminal strip
connectors and 1/4" phone jacks. High-quality,
low-distortion input and output transformers providing
30Hz-20kHz response (±0.15dB) are optional, and
installation requires no soldering.

A security cover is included with the E-232 to guard against
disturbance or tampering. The E-232 occupies one
standard EIA rack space.

FEATURES

1. 14 filters on ISO 2/3-octave center frequencies from
40Hz to 16kHz.

2. Continuously variable 6dB or 12dB of boost or cut at
each center frequency.

3. High-quality, minimum phase shift active filters.

4. Noiseless center-detent slide controls with
precision-calibrated linear scales.

5. Continuously variable highpass filter with wide control
range.

6. EQ In/Out switch for manually bypassing equalizer.

7. Automatic EQ bypass circuitry in case of AC power loss.

8. LED peak indicator monitors input and output levels, for
proper gain structuring.

9. Variable input level control allows a variety of input levels
and sources.

10. Optional isolation transformer (LT-101) for converting
unbalanced inputs to balanced.

11. Security cover is included.

SPECIFICATIONS

PERFORMANCE:
Frequency Response

Total Harmonic Distortion
Hum and Noise

INPUT & OUTPUT:

Input

Input Impedance
Rated Input Level
Maximum Input Level

Output

Output Impedance
Rated Output Level
Maximum Output Level

CONTROLS & PANEL FUNCTIONS:

(Front Panel)

Equalizer Sliders

Bands
Center Frequencies
Boost
Cut

Input Level Control
Highpass Filter

Pre-Peak Indicator
Power

(Rear Panel)
Input

Output
Ground

POWER:
Power Requirements
Power Consumption
PHYSICAL:
Finish

Front Panel

Case

Dimensions (W x H x D)
Net Weight

OPTIONAL

ACCESSORIES:

* 0dB is referenced to 0.775V RMS

20Hz to 20kHz (+1.0, -2.0dB)
Less than 0.01% at 1kHz, all sliders at 0 position,

rated output

-98dB (EQ in, IHF-A, all sliders at 0 position)

30k ohms (Input level control set at 0 position)
+4dB* (Input level control set at 0 position)
+32dB (Input level control set at -12dB)

1k ohm
+4dB*
+20dB*

14

Standard ISO center frequencies from 40Hz to 16kHz

+6dB or +12dB (Selectable each channel)

-6dB or -12dB (Selectable each channel)
±12dB
Adjustable -3dB frequency: 15Hz to 300Hz,

12dB per octave

Red LED (Lights when input or output

reaches 3dB below clipping)

On/Off push switch with green LED indicator

Screw terminals (H=Hot, C=Cold, E=Ground),

unbalanced 1/4" phone jacks

Screw terminals (H=Hot, C=Cold, E=Ground),

unbalanced 1/4" phone jacks

Signal Ground to Chassis Ground

AC mains, 50/60Hz

11 watts (120V version); 13 watts (220-240V version)

Aluminum, black
Steel, black
483 x 44 x 311mm (19.0 x 1.7 x 12.2in.)

EIA rack mount

3.8kg (8.4lbs.)
LT-101 Input Transformer

APPEARANCE AND DIMENSIONAL DIAGRAM

Unit: mm (in.)

ARCHITECT’S AND ENGINEER’S
SPECIFICATIONS

The dual-channel equalizer shall contain 14 filters on ISO
center frequencies from 40Hz to 16kHz. Each filter section
shall provide 6dB or 12dB of cut and boost at the center
frequency, with linear slide control operation and a graphic
display of the equalization curve. An internal switch shall
allow independent selection of both the boost and the cut
range for each channel. The filters shall be minimum-phase
type. The equalizer shall contain a highpass filter having
the following characteristics: -12dB/octave with -3dB point
continually adjustable from 15Hz to 300Hz. The equalizer
shall be provided with an EQ bypass switch to remove all
equalizer and end-cut filters from the signal chain, with an
LED indicator showing status. The input circuit shall be
electronically unbalanced, and capable of driving a load of
1k ohm or higher. The unit shall accept optional LT-101
input transformer which shall be internally installed by

means of standoffs and plug-in connectors. The unit shall
contain a relay circuit which bypasses all internal
electronics in the event of power failure. An output muting
function shall be provided to suppress turn-on and turn-off

transients. Barrier strip connectors and unbalanced 1/4"

phone jacks shall be provided for input and output signal

wiring. The unit shall be provided with a front panel power

switch with an LED indicator showing Power On status. The
input amplifier shall include a gain control with a ±12dB
range. An LED indicator shall be supplied to monitor both
input and output levels and shall illuminate when either
comes within 3dB of clipping. The unit shall measure

483(W) x 44(H) x 311 (D)mm (19.0" x 1.7" x 12.2”) with rack

mount ears attached, and shall occupy one standard EIA
rack space. A smoked plastic security cover shall be
provided. The equalizer shall be the TOA E-232 2/3-octave

graphic equalizer.