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the threshold by watching the LED gain-reduction meter, and voilà ,
you have an automatic level control for the entire system. I found
this especially useful for jazz, fusion, and classical music, or very
dynamic music with percussion or slap bass that seems to come out
of nowhere. By setting a reasonable threshold, I could keep the
power amps and speakers running at an extremely high level and
let the L-1102 keep the sudden transients and loud passages from
either (1) sending me dashing for the mixers output sliders, or (2)
listening to the entire system go blaaaaaaaapfrom clipping dis-
tortion. Just like its leveler mode, the L-1102s limiter mode does
the job silently, quickly, and reliably.
I like having two independent processing units in one rack
enclosure. Being able to apply one channel as a limiter and one as a
leveler is great for mono PA systems; you can use the limiter to
preserve your house speakers while setting the leveler to guard the
monitors. Its also good for biamplification setups, where you might
want to keep tighter reins on, say, your expensive high-frequency
drivers.
Like the front panel, the L-1102s rear panel is clearly laid out,
with both channels busses completely identical. I like the ground-
screw terminal, designed so that you can remove its metal shorting
piece if ground loops are a problem. Similarly, I like the plastic
covers that screw on over the sensing terminals. Im not ex-
traordinarily clumsy, but its nice to know that if I were to slip with
a screwdriver, I wouldnt be able to short out my power ampsspeaker leads by bumping the sensing screws. Its a small point, but
it shows good design on TOAs part.
Overall, how does the L-1102 stack up? Very well, not only in
terms of how it functions, but in how easy it is to operate. In an age
when signal processors are often buried in knobs and switches, its
refreshing to use a leveler/limiter thats so straightforward. Its
clean, quiet, and well-made. I highly recommend TOAs L-1102
Dual Leveler/Limiter for onstage, studio, and broadcast ap-
plications.
TOA L-
1102 Dual Leveler/ Limiter
Type of unit:Leveler/limiter
Features:Two channels that can operate inde-
pendently in leveler or limiter modes, stereo
linkability, sensing inputs, extremely low noise,
single-rack-space configuration
Power requirements: AC mains, 50 Hz/60 Hz
Power consumption: 14W (120VAC version),
or 15W (220/240VAC version)
Frequency response:20 Hz to 20kHz (±1dB)
Total harmonic distortion:Under 0.1%, 1kHz, rated output; under 0.2% 1kHz, 30dB compression
Input:+4dB for 10k-„¦balanced load
Output:+4dB for 600-„¦balanced load
Maximum input level:+20dB
Maximum output level:+20dB
Sense input: 100k-„¦(electronically balanced)
Noise level: Under -92dB (IHF-A)
Threshold level range: Leveler, -40dB to 0dB (with
respect to input); limiter, 1V to 100V RMS
(with respect to sense input)Noise gate threshold range:-80dB to -40dB
Attack and release times:Dependent on input (or
sense input) signal
Finish:Black
Dimensions: 19" x 1.73" x 12.47" (482.6mm x
44.0mm x 316.8mm)
Weight:8.8 lbs (4.4kg)
Manufacturers address:TOA Electronics, Inc.,
601 Gateway Blvd., Ste. 300, South San
Francisco, CA 94080
INSIDE TOA S L-
1102 D UAL L EVELER /L IMITER
CH 1 ECHOUTPUT INPUT SENSE+ -“ ECH
+ -“
OUTPUT
INPUT
From Mixer, Preamp, Etc.
Power
AmplifierL-1102
Leveler/Limiter
To Speaker
(THRESH) (10V)
(THRESH) (-20dB)
POWER AMP OUTPUT
OUTPUT
OUTPUT: (10) (+20dB)
OUTPUT: (0) (0dB)
INPUT
INPUT -20
-40 0 dB1 10 100 Vrms
-20 -400dB
A
10:1
Connections for limiter operation (one channel). The wires
between the power amps output and the L-1102s sense input are
unnecessary when the unit is used as a leveler.
The top diagram shows the compression curve of the L-1102 in
limiter (speaker protection) mode. Output amplitude is linear
with respect to input, up to the threshold (A), and gentle and
constant thereafter for compression in the ratio of 10:1. The
bottom diagram (leveler) shows compression of an output signal
when the input level exceeds a predetermined threshold. The
effects of 0dB and +20dB output-level settings are also shown.
