Operation, Controls Volume Control, Gain Selector

4.0 OPERATION

4.1 Precautions

Only connect the VORTEX amplifier to a appropriate AC circuit and outlet, according to the requirements indicated on the rating plate label.

NOTE: Even under normal conditions the mains current can reach levels (up to 60 A / 230 V and 120 A / 115 V); this could cause lamps to flicker if connected to the same mains as the amp. The impedance of the AC circuit should be less than 0,157 Ohms to avoid flicker according to EN61000-3-11. Ask / inform your local power provider. Don’t even think about measureing this with your ohmmeter. This may damage your meter, caution - high voltage hazards!

4.2 Controls

4.2.1 Volume Control

A microprocessor-controlled DCA (Digital Controlled Attenuator) with a control resolution of 12 bits per channel is integrated into the signal path. This means that the signal is not subject to an A/D followed by a D/A conversion with associated losses. Each channel is governed by a linear potentiometer with 41 notched settings. These settings have been selected to correspond to human hearing characteristics (logarithmically) and therefore guarantee an optimal range of settings for practical applications. Each channel can be set individually except when operating in mono mode whereby only ChA is active.

Using an intelligent DCA control (Digital Controlled Attenuator) instead of the “conventional”VCA results in considerably reduced distortion as well as

improved noise characteristics. The implementation is comparatively simple: the volume potentiometers pass the relevant control information (quieter or louder depending on the adjustment made to the potentiometers) to the microprocessor. The microprocessor then adjusts the power amp output using various strategies implemented in software. In addition to improved technical parameters, this approach allows a significant reduction in the number of components and circuits required.

The volume pots are also used to set the CAI-address. (See 5.2.3, CAI Address Settings)

4.2.2 Gain Selector

A switch on the rear of the VORTEX allows the maximum amplification attainable to be set directly in the input stage.

GAIN			The VORTEX amplifier has a 26 dB and 32 dB
GAIN			voltage gain setting along with a 1.4 V
26dB		1.4V	sensitivity setting.
26dB		1.4V	sensitivity setting.
	32dB

4.2.3 Limiter Switch

This switch is located at the rear of VORTEX. It allows you to set the mode of the limiter. There are three modes:

LIMITER		Right position:
LIMITER		Clip Limiter: ON & Speaker Protect: ON
OFF		SpP Clip
	SpP
LIMITER		Middle position:
		Middle position:
		Clip Limiter: OFF & Speaker Protect: ON
OFF		SpP Clip
	SpP

P.16	CAMCO USER MANUAL
	VORTEX POWER AMP SERIES