The 215L design is a passive low pass filter with a slope of only 6 dB per octave, and a
passive dual high pass filter with a slope of 12 dB per octave. The filters are isolated from
each other with the same discrete transistor buffer used in the famous 550 series equalizers.
This minimizes interaction between the filters, as well as providing a low impedance source for
the filter following the buffer.
The input section is a balanced circuit using the API 2510 all discrete op-amp, minimizing the
loading effect on any device plugged into it. The output stage is a transformer balanced
output, driven by the all discrete API 2520 op-amp.
The filters are both continuously adjustable, with a range from 20 Hz to 20 kHz in two bands.
The low pass filter has a range from 500 Hz to 20 kHz, and the high pass filter has a range
from 20 Hz to 600 Hz. This covers a broad range of frequencies throughout the entire audio
spectrum.
Because of the subtle nature of the 215L filter, it finds a home with uses like rolling off the
low end of a hi-hat, where a natural sound is desired, not the usual "phase-shifter" sound of a
18 to 24 dB per octave filter found on most consoles. It can also be used to thin out room
mics, without a complete loss of low end, again, resulting from steep filter circuits.
The 215L can be used in the Legacy Series Consoles or in the L200 Rack. The 215L Filter
makes use of the 2520 and 2510 op-amps and therefore exhibits the reliability, long life and
uniformity which are characteristic of API products.
d. 225L Discrete Channel Compressor
The API 225L Compressor is ideal for all studio, live sound and broadcast applications.
Regardless of the threshold or ratio settings, the output level always remains at unity. This
unique feature allows real-time adjustments without changing the output level. Both "feed
forward" (new) and "feed back" (old) gain reduction methods are selectable on the front
panel. There also is a SOFT or HARD selector for either an "over easy" compression resulting
in a very natural, uncompressed sound or a typical sharp knee type that has a much more
severe limiting effect. The 225L is designed for individual channel use or two units can be
combined for Stereo applications via a rear access pin. The 225L also has a side chain input
for the detector amplifier.
Features:
•
Threshold control from -20 to +10 dBu
•
Variable compression ratio from 0 to infinity
•
Adjustable release time from 50ms to 3 sec
•
"Old" or "New" sound
•
HARD or SOFT compression knee
•
Always at unity gain, regardless of settings
•
LED Gain Reduction meter
•
API 2510 and API 2520 op-amps
•
Transformer output to +28 dBu
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Страница 30: ...3 5 1068L Input Module ...
Страница 146: ...The diagram below indicates which 1068L parameters are controlled by the automation or recall system ...
Страница 232: ...The diagram below indicates which 1068L parameters are controlled by the automation and recall systems ...
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