User manual ASL INTERCOM ROXX 301

[. . . ] Boosting a headphone output Whenever the headphone output power of any equipment is not sufficient, the Personal Headphone Amplifier can be connected to that headphone output. The output power of the PHA will be high enough for most circumstances/purposes. Checking microphone signals Very usefull to, for instance, boom operators. Trouble shooting A sound engineer can check lines, microphones or outputs, to locate signals or to solve problems. [. . . ] * When the Personal Headphone Amplifier is prepared for charging Ni-MH batteries within the unit, the external DC voltage can range from 12 V to 18 V. The adaptor must be capable of delivering a current of at least 700 mA. 17 Internal battery compartment Accepts 4 AA-type 1. 5 volt batteries or 1. 2 volt rechargeable cells. The Personal Headphone Amplifier can be modified so that Ni-MH cells can be charged in the unit. Consult your distributor for more information 18 Beltclip Open the battery compartment on the side of the unit A S L C O M M U N I C A T I O N S Y S T E M S RoXX-Series 301 Manual by turning the knurled screw anti-clockwise. Put the holder back into the unit, with the holders connection terminals pointing to the side where the beltclip is mounted. Close the battery compartment by putting back the little coverplate and turning the screw clockwise. The Personal Headphone Amplifier is now ready to operate on batteries. The ASL RoXX -Series 301 can be switched on by pushing the power button (1). The unit will start whenever the total battery voltage is higher then 4. 0V. When the unit switches off because the battery voltage is lower than 2. 5V, the batteries will start to recover a bit. The battery voltage rises, and when it exceeds 4. 0V, the unit will switch on again. By then, the battery voltage will again go down, resulting in switching off the unit at 2. 5V. This frequently and automatically switching on and off means that the batteries are empty and that they should be replaced. The ASL RoXX -Series 301 Personal Headphone Amplifier can be modified for charging four Ni-MH cells in the unit. Whenever a RoXX 301 is prepared for charging Ni-MH cells, normal batteries should not been used anymore and reverse voltage protection for the cells does not work anymore!Mains Operation The ASL RoXX -Series 301 Personal Headphone Amplifier can be powered by mains by using a mains adaptor (not supplied with the RoXX 301). Choose an adaptor with an input voltage that matches the local mains voltage. The output of the adaptor needs to supply a DC-voltage between 9 and 24V at a current of 500mA (12 to 18V DC at a current of 1A when the RoXX 301 is prepared for charging Ni-MH cells). Connect the adaptor via an appropriate plug to the DC-in socket (16) at the side of the RoXX 301. Always turn the unit on and off without the headphone on your head. Connecting and Monitoring Balanced Signals The ASL RoXX -Series 301 Personal Headphone Amplifier has an independent section for balanced signals and one for unbalanced signals. Speaker signals should not be connected to the balanced input (they are mostly unbalanced and can be monitored with the unbalanced section of the ASL RoXX -Series 301). Before connecting any balanced signal to the XLR connectors, turn the Balanced input Volume control (10) down. Connect the balanced signal to one of the XLR connectors (the other one is for loop thru, the male and female connectors are paralleled). [. . . ] Please check the specifications of your headphones if they can handle the output power of the Personal Headphone Amplifier. The Built-In Limiter The ASL RoXX -Series 301 Personal Headphone Amplifier has a built-in stereo limiter to prevent the output amplifiers from clipping. The limiter range is 30 dB for the balanced input and 25 dB for the unbalanced inputs. So when the output level of the RoXX 301 reaches the threshold level of the limiter, the input signals can become 25 or even 30 dB higher before the output amps will actually clip. If clipping occurs in one of the input stages of the ASL RoXX -Series 301, the limiter can't do anything against it. [. . . ]