Cloud CX335 Spécifications télécharger pdf (Page 20)

CX335 Technical Manual Page 19

9.08

Re-check the 0dB level as per test number 9.04 for both channels. If there is a large

discrepancy, then the calibrations described in 9.07 will need to be re-run.

Dynamic Observation - where the oscilloscope displays are subjective.

9.09

For the dynamic observations listed in section 9.09 and onwards, you will need test signal

bursts or 'sequences' set to three different levels, and available at two different

frequencies. For factory calibration the two signal sequences are as follows:-

Tone sequence one:

A signal of 0dB at 1KHz for a period of 300ms; immediately followed by a signal of -15dB

at 1KHz for a period of 300mS; then a synchronisation period of silence again for 300mS.

Tone sequence two:

A signal of 0dB at 80Hz for a period of 500ms; immediately followed by a signal of -15dB

for a period of 500mS; then a synchronisation period of silence again for 500mS.

The silence period in each sequence should hopefully provide enough of a level change

for the oscilloscope to trigger reliably, providing enough signal level offered to the

oscilloscope.

9.10

Due to the CX335 front panel control ranges having an important effect on the audio

signal, it is important that the test equipment and controls are set very similarly to the

following descriptions. It is possible that any discrepancy will produce a vastly different

oscilloscope display, which might mislead or confuse the final tests and observations.

The front panel of the unit must be initially adjusted as follows:-

Slow switch released. (Out).

Hard switch depressed. (In).

Compressor Threshold rotated fully Counter Clockwise to about '-8dB'. (This being

midway between the two test sequence levels of 0dB and -15dB)

Compressor Ratio rotated fully Clockwise to infinity to 1.

Peak Level setting rotated fully Clockwise to '+26dB'.

Output Gain set so that the test sequence displays full scale during the 0dB level section

of the sequence, taking care that if any rotation away from the detent is required, then this

Gain make up amount should be a positive value, otherwise the later Peak observations

will be incorrect, as Peak will be ineffective.

Bypass / Normal released. (Out).

Set the oscilloscope as follows :-

Input gain to display 0.5 Volts / div (D.C. coupled)

Timebase to 20mS / div (or slower if more screen persistence is available). The

representations of the oscilloscope displays (fig 9.01 / 9.04) have being shortened in time

during the linear part of the wave so that the envelope seems to appear on one timebase

'pass' of the display. In reality the test sequences necessitate that two 'passes' of the

display are required to view the whole envelope.

9.11

Apply the 1KHz test sequence as described above. The waveform in fig 9.01 can be seen

at the output, verifying the correct operation of the timing circuits in the HF section of the

side chain. The attack portion of the waveform should respond somewhere in between

25mS and 30mS. The release section taking upwards of 150mS.

9.12

Press the Slow switch, note the changes to the output in fig 9.02. The attack and release

times will be greatly extended. (Attack 200mS or more , Release greater than 600mS) ,

as shown in the diagram fig 9.03.

1 2 ... 15 16 17 18 19 20 21 22

Commentaires sur ces manuels

Pas de commentaire

Cloud CX335 Spécifications Page 20

Commentaires sur ces manuels

Produits connexes et manuels pour Compresseurs d'air Cloud CX335