INPUT/OUTPUT GAIN
AND OTHER INTERNAL ADJUSTMENTS
Analog input/output alingment
The 8X192 ADDA analog input/output sensitivity comes as factory default fixed at -15dBFs
corresponding to +4dB (OVU=1.228VRMS measured between hot and cold). This gain is
optimal for most situations and unless another level "is necessary for systemic reasons, we
recommend leaving the gain at the default setting. If the gain has to be changed the
appriopriate jumpers and trimpots have to be accessed by lifting the top cover. Please
review the drawing on following page.
The gain alignment does not affect audio quality, only input/output sensitivity. A small
tweaker or screwdriver is necessary. First you have to arbitrarily decide what will be your
studio "0 VU" analog/digital reference level. It is usually between -20 and -14dB. It defines
how much headroom is left over the normal operating "0 VU" level. You may set it at the
same level as other piece of equipment in your studio.
Step 1 - Analog output alignment
Step 2 - Analog input alingment
1. Play a digital audio source (DAW generator, test CD etc.) set to approx. 1kHz at the peak
operating level you have chosen (let's say you have chosen -18dB).
2. Send the signal from the analog output to the console VU meter. If you don't have a VU
meter you can use an AC voltmeter set to measure AC RMS values. "0 VU"at + 4dB
corresponds to 1.225 Volts RMS measured between pin hot and pin cold of the output
signal.
3.Using a tweaker or a small screwdriver adjust the analog outputs until the VU meter reads
"0 VU".
4. Repeat the same for all outputs.
1.Set the oscillator in your console at 1kHz and "0 VU". Send the oscillator to the
8X192ADDA analog input."0 VU" at + 4dB corresponds to 1.225 Volts RMS measured
between pin 2 and 3 of the output XLRs. If you do not have an analog oscillator, you can
use a calibrated analog out of a DA converter and generate a sinewave inside the DAW.
Alternatively, if you do not have an oscillator you can use the analog outputs you have just
aligned as a source of a sinewave at +4dB (generating sinewave digitally as in step 1).
2.Select the "analog input". Connect a digital meter to a digital output. If you don't have a
dedicated digital meter use the most precise meter available in you existing digital recording
equipment or DAW.
3. Adjust the analog input level to get appropriate reading of the meter
(for example -18dB).
4. Repeat the same for all of the analog inputs.
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Summary of Contents for 8X192 ADDA
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