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Headphones, Personal Listening Gear Personal Listening at its Best

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  #11  
Old 12-02-2017, 03:21 PM
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THE VOLUME CONTROL The desired volumes for left and right channel are set simultaneously by means of the “VOLUME“ control. Volume can also be set via remote control. For this purpose, the volume control is actuated by a servo motor. Manual operation of the knob at the same time is possible without the risk of damage (although not useful…). Press the rocker button “Volume Up/Down” in order to increase or decrease volume. Pressing “left/right” on the directional pad will have the same effect.
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Old 12-02-2017, 03:22 PM
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BALANCE CONTROL is provided to compensate moderate level differences between left and right channel. These may root in the recorded material itself, noticeable differences between left and right headphone system, or differences in the user’s individual hearing. All of the above can be carefully compensated. The balance control offers a precise center detent in case no adjustment is necessary. In order not to impair the V281’s perfect crosstalk specs, it takes effect on the right channel only.
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Old 12-02-2017, 03:22 PM
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THE AMPLIFIER The input signals are fed to an amplifier stage especially designed for this application, with eight transistors per channel. The V281 houses no less than four of those ! Channels are physically separated from each other to ensure optimum crosstalk rejection. The frequency range covers 5 Hz ... 70 kHz (-0.5 dB) or 3 Hz…200 kHz respectively (-3 dB), in order to ensure fully linear performance within the entire audible range. Overall gain is set to +8 dB (unbalanced) or +14 dB resp. (balanced) to ensure sufficient volume reserve also for high-impedance headphones.
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Old 12-02-2017, 03:23 PM
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Too loud ? Too soft ? The PRE-GAIN method The V281 is specially designed to drive headphones. Headphones however can present load impedances from 8 to 2000 ohms and efficiency ratios from 85 to 115dB per milliwatt. Thus it can be quite tricky to fulfil all demands, since... … owners of high-efficiency headphones will rarely set the volume control higher than 9 o'clock in order to exclude hearing damage, while ... the maximum setting may still be too soft for low-efficiency headphones, but … all users expect highest quality at lowest noise and distortion. Thus, the circuitry must adapt itself as the headphone won't !
WE CALL THE SOLUTION TO THIS PROBLEM PRE-GAIN
The alignment between amplifier and headphone is provided by the preamp stage, which can boost or attenuate the input signal in four steps of 6dB each. For this purpose, two switching devices are located on the rear panel for left and right channel individually.
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Old 12-02-2017, 03:25 PM
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PRE-GAIN
The alignment between amplifier and headphone is provided by the preamp stage, which can boost or attenuate the input signal in four steps of 6dB each. For this purpose, two switching devices are located on the rear panel for left and right channel individually.
CAUTION !! The switch settings should be altered under the following conditions only: - The unit must be switched OFF - the "VOLUME" control must be set to minimum - left and right channel settings should ALWAYS be set the same - never increase the setting by more than ONE switch per channel
If you find your HPA V281's volume could be somewhat softer (in order to improve volume control range e.g.), push the switch labelled "-6 dB" (half gain) or "-12 dB" (quarter gain) in upward direction. If you find your HPA V281 should provide more gain, do so with the switch labelled "+6 dB" (double gain) or "+12 dB" (quadruple gain).

Ex-factory, all switches are set to their lowest position - i.e. 0 dB or unity gain - which should be sufficient for most applications.
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Old 12-02-2017, 03:29 PM
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DE- / ACTIVATING THE HEADPHONE OUTPUTS The headphone outputs can be activated or deactivated by pressing the “HEAD“ button on the front panel. The green LED displays the activated status. This function can also be switched via remote control. Press „RED“ ( the red button).
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  #17  
Old 12-02-2017, 03:30 PM
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THE BALANCED HEADPHONE OUTPUT The HPA V281 offers a balanced headphone output. This is equipped with a gold plated female 4-pin XLR connector.

UNBALANCED HEADPHONE OUTPUTS The HPA V281 offers two stereophonic headphone outputs, each equipped with a 1/4" (6.3mm) jack socket. Because HPA V281 offers 4 channel amplifier (2 x stereo), each socket is driven by a dedicated stereo amplifier Please note: the RIGHT phone jack is connected to the in-phase stereo signal, whereas the left phone jack is connected to the 180 phase shifted signal.
Balanced
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Old 12-02-2017, 03:31 PM
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ACTIVATING / DEACTIVATING THE LINE OUTPUTS The line outputs can be activated and deactivated by means of the “LINE“ pushbuttons on the front panel. The green LED indicates the activated status. This function can also be switched via remote control: Press “GREEN“ (the green button)
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Old 12-02-2017, 03:31 PM
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PRE-POST FADER or FIXED-VARIABLE The line-out signal can be tapped at two different points within the V281’s signal path. If you wish to make use of the input signal without any level change – for a device with its own level controls or recording purposes e.g. – the Fixed-Out or Pre-Fader path (prior to level control) is the right choice: In this case, the unaltered INPUT signal (prior to level control) is forwarded to the line output. If you want to feed a power amplifier or active loudspeakers, VariableOut or Post-Fader (including level control) should be used. In this case, the line output provides the signal at the level set by the volume control. The V281’s line output offers further possibilities: - balanced-in to balanced-out - unbalanced-in to balanced-out - balanced-in to unbalanced-out - unbalanced-in to unbalanced-out
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  #20  
Old 12-02-2017, 03:34 PM
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Switching between “Pre“ and “Post“ is effected via software: Press and hold the “LINE“ pushbutton for about two seconds until the green LED starts flashing. The present status is displayed by the “XLR” LED (pre fader) or the “DIG” LED (post fader). The setting can be altered now by pressing the corresponding button. To complete the setting procedure, just press and hold the “LINE” button again until the green LED stops flashing.

LINE-OUTPUT LEVEL can be set by means of internal DIP switches located on the line-out circuit board. See page 33 for further details. Generally, the level at the unbalanced output will equal the input level in pre-fader mode, or with the level control set fully clockwise in post-fader mode. By means of the DIP switches however, relative attenuation/gain can be set to –12, -6, 0, +6 or +12 dB. Please note that output level at the balanced output is generally +6 dB higher than at the unbalanced output.

THE “MUTE“ FUNCTION serves to mute ALL outputs. On the V281, it can only be activated via remote control.
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