User manual SENNHEISER UNIPOLAR 2002

[. . . ] Description This electrostatic headphone system contains two basic parts: the headphone "unipolar 2002" and the supply unit HER 2000. The supply unit delivers the necessary stepped-up audio voltage to operate the transducers in the headphone. Without this supply unit the headphone cannot be used The headphone must never be connected to any other source. [. . . ] Supply unit: The headphone unit HER2000 6 can leed two headphones "unipolar 2002". the headphone plug 15 May be connected to either of the two output sockets 11 or 12 If a headphone is inserted into the socket 12 then its volume only depends upon the setting 01 the volume controlaI the Ieeding amplilier. If the headphone - or a second headphone - is connected to socket 11 the loudness 01 this output may be pushbutton attenuated by means of the three buttons 8 When the button "0 dB" is pressed down both headphones are equally loud. iI you push "-6 dB" "-12 dB" the volume at the output 11 iis reduced by the selected value. This way two listeners may enjoy headphone listening at different output levels. Another feature of the supply unit is the pushbutton 7 which allows to select between loudspeaker and headphone operation. In the down position the headphones are operative and, il the button is released, the connected loudspeakers are in the circuit. The excellent sound quality of this electrostatic headphone system "unipolar 2002" allows to detect the finest sound structures and nuances. In order to maintain this high quality even at high sound pressure levels the supply unit HER 2000 is litted wlth two LEDs to monitor the beginning of an overload condition. the indicator 10 monitors the left and 9 the right channel. These diodes start to light up when the laintest distortlon appears which is still undetectable by ear. This starting point is at approximately 117 dB peak sound pressure level. We would like to point out that volume levels of that magnitude are already considered dangeraus to the ear by hearing specialists when listening over an extended period of time. Therefore we recommend to set your peak volume level always to a value below the point where the LEDs light up. This also eliminates the generation of any undesired additional distortion in the headphones The transducers in the headphones are effectively protected against overload through electrical measures in the supply unit and can thus hardly be destroyed even during langer lasting overload periods. the audible effect of an overload is that the headphones reproduction volume is reduced to a very low value. [. . . ] Sound pressure level Max tolerable voltage applled THDat 1000 Hz/110 dB Sound coupling to the ear Great care has been taken to manulacture a perfectly sale headphone and connection cables. Please observe the following in order to always keep your equipment in this safe condition: 1. Never use any sharp pointed objects to pierce headphone parts or connection cables or any part of the supply unit! [. . . ]