General

The "unipolar 2002" is the world'slirst electrostatic headphone with a 2-way system without diplexer. Through the concentrically arrangement 01 both systems in one plane the distortlonless reproduction 01 an unusual wide Irequency range is achieved.

Another leature 01 the headphone is the exceptional high efficiency, so that a high reproduction volume can be adjusted easily.

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.

Headphone: The headband 1 is fitted with an adjustable headcushion 2 and can be easily set to a comfortable position for the listener by means 01the cushion adjustment 3 . The two headphone shells are colorcoded by cable sleeves 4 and 5 : red = right channel, yellow = left channel. The connector15 is to be inserted into the sockets 11 or 12 on the supply unit.

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. The headphones resume normal operation after a few seconds when the cause for the overload condition has been removed.

For normal operation and maximum volume the "unipolar 2002" must be connected to apower amplifier of at least 15 Watts at 8 Q (30 Watts at4 Q) per channel. HiFi ampliliers up to a power output of 150 Watts may be used without

danger for the headphone systems of the headphones since the protection Clrcuit mentioned above becomes effective at extreme overload conditions.

Caution should be exercised when high powered super ampliliers above 150 Watts per channel are used. The headphone operation with such amplifiers is perfectly safe when during on-off or programs switching the volume control is in a minimum position and the headphone's level is brougt up after such operations. Very high transient

voltages are capable to activate the protection circuit irreversibly. This protective condition can only be corrected by an authorized service technician.

Connection to your HiFi-system

1. Connection to DIN-Ioudspeaker sockets

Plug the connectors 13 into the loudspeaker outlets 01your amplifier or receiver. Red = right channel, yellow = left channel. Your loudspeaker cables are then simply connected to the rear 01the plug 13 . By means of the pushbutton 7 on the supply unit 6 you may now select either loudspeaker or headphone operation (see fig. 1)

2. Connection to loudspeaker screw-on terminals

1The connection cable 14 of the "unipolar 2002 Set X" supply unit is fitted with cable lugs and insulated clip-on connectors If your amplifier is fitted with such terminals connect the supply unit as shown in fig 2 or Iig 3 as lollows:

\a) Amplifiers with several switchable loudspeaker output groups:

This connection scheme (Iig. 2) can be optimally used for the headphone only if the secondary outputs 01the ampli-

lier have no internal series resistors. If resistors are in the amplifier'soutput circuit slight roll-off at the very low and very high end may result, wh ich may not be noticeable by ear. If this is undisered the headphone should be connected as Indlcated in the lollowing scheme b). This means that loudspeaker and headphones should be connected to one of the outputs and the switching facillty of the supply unit is used.

b) Amplifiers with single stereo screw-on terminals:

When the supply unit and the loudspeakers are connected as shown In fig. 3 the mode of operation - loudspeaker or headphone- maybe selectedby the pushbutton7 . II only the "unipolar2002" is connectedto the amplifier the black and the grey leads are not used and remain unconnected. Pushbutton 7 must then, of course, be in the down position.

Important notice:

Electrostatic headphones operate with high drive voltages. 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!

2.

Defective housings, connecting cables and connectors are immediately to be taken out 01service and repaired

 

Transducer

 

 

 

 

Frequency

response

 

 

Matchlng Impedance

 

 

Sound pressure level at 5 V

 

Max. sound

pressure

level

 

Max tolerable

voltage applled

 

THDat

1000 Hz/110

dB

 

Sound coupling to the ear

1

Headband

pressure

 

)

 

Cable

length

headphone

Cable

length

supply

unlt

Dimensions

HER 2000

 

Welght

headphone

 

 

Welght

supply

unlt

 

electrostatlc

16 22000 Hz

4 - 8 Q (Ioudspeaker output)

109 dB

117 dB 8t 1 kHz

~5 VRt;!S ~ 0,1 m

ClrcumaLJra!, via acoLJstically closed leatherette cushlon wlthout ear contact

appx. 4,5 N (460 pi 3m

1,510

75x65x184mm

appx. 345 9 appx. 1600 9

by an authorized service technician!

3. Unauthorized opening of headphone shells or the supply unit voids warranty and may impair the performance

and safety of the equipmentl

We reserve the right to alter specitications, in partlcular with regard 10technicallmprovements.