Sound Performance Lab 9320, 9319 owner manual Power supply, Surround Processor Stereo Width

filter intervenes at low frequencies. If the MID-HITUNE filter is at 1 kHz, the HARMONICS filter affects higher frequencies. The characteristics of the two filters therefore complement each other in an ideal fashion.

The IN switch switches the SURROUND PROCESSOR on or off. The status-LED indicates, that the SURROUND PROCESSOR is activ. The IN switch works only when the VITALIZER ACTIVE switch is activated.

In case you want to monitor the SURROUND PROCESSOR in isolation, switch VITALIZER ACTIVE on and set the PROCESS and HARMONICS control fully counter

clockwise.

The STEREO WIDTH potentiometer controls the stereo image.

Working on estabilshed inter-channel phase principles, the STEREO WIDTH control is be used to increase the subjective soundstage width of any stereo source. The off-centre signals of the stereo source are detected and fed back to the opposite channel phase inverted.

This effect can be applied to overall mixes as well as to single instru- ments. Very interesting is the spreading of the stereo image of overhead mics of drum-sets or choruses or horn sections.

7Surround Processor

In

8Stereo Width

Based around a toroidal transformer, the integral power supply is designed to minimize induced hum and noise due to the non existence of an air-gap.

On the XLR/jack-version (9320) the primary voltage may be selected between 230V/50Hz and 115V/60Hz by means of a recessed slide switch on the rear panel. The jack-version is set according to local requirements.

The XLR/jack-version (9320) features a rear-panel ground-lift switch which may be used where ground loops are causing hum problems. When the GND LIFT switch is set to off, the circuit ground is no longer connected to the chassis ground. The power cord connector is a 3-wire, U-ground, stan- dard IEC mains connector for a detachable power cord (enclosed).

The unbalanced jack version (9319) has a two wire power cord obviating the need of the ground lift switch.

Transformer, power cord and mains connector have VDE, UL and CSA approvals. The fuse has a value of 200mA.

On the secondary side of the power supply, an RC combination is used to filter out noise and hum voltages from the mains side. Both half-waves are smoothed with 2200 μF capacitors in the positive and negative voltage path. Both pathes are calibrated separately via trimmers, as deviations of only a few millivolts can result in audible changes such as a diffuse sound pattern. After the calibration stage, the current is again smoothed.

Power supply

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