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12

Front Panel Controls

The LS28 has two microprocessor-driven 

rotary controls and six buttons (Power, 

Menu, Enter, Mono, Invert, and Mute).

Left Rotary control (Input Select)

Select input by rotating the control to the 

left or right. The screen displays the current 

input on the left side of the display.

Right Rotary control (Volume)

Adjust volume (output level) up or down 

for both L and R channels. Volume control 

is also selectable via VOL UP and VOL DN 

buttons on the remote control. Volume 

adjustment is indicated in the display 

window by numeric digits on 0–103 scale.

Do not turn volume up beyond normal 

listening levels when ‘mute’ is engaged to 

avoid unexpected or possibly damaging 

sound levels.  Reduce volume level 

whenever changing input sources, even 

when muted.

The right rotary control also functions to 

change settings when in menu mode.

Power On/Off

Supplies power from A.C. wall outlet 

to preamp; indicated by active display 

window. The LS28 requires approximately 

45 seconds to warm up; this time is 

required to stabilize the vacuum tubes. See 

‘Start-Up Procedure’ on page 11 for details.

Menu

The menu button enters the setup menu 

of the LS28 to allow customizing certain 

settings of the preamplifier. See page 15 for 

further details about using the setup menu.

Enter

The enter button is used in conjunction with 

the Menu button to make changes to the 

systems settings of the LS28.

Mono

Toggle between Stereo and Mono output.

Invert

The invert button allows the absolute phase 

of the recording to be switched between 

‘normal’ (in-phase) and ‘invert’ (180° 

inversion).

Mute

When activated, Mute electrically disables 

all outputs of the preamplifier; indicated 

by ‘MUTE’ in display window, beneath the 

volume number.  This control should be 

activated before switching inputs, changing 

connections or shutting down your audio 

system to help protect your amplifier and 

speakers from unexpected signal pulses. 

When deactivated, ‘MUTE’ is cleared 

from the display window allowing normal 

operation.

Operation

Содержание LS28

Страница 1: ...LS28...

Страница 2: ......

Страница 3: ...gin listening however please take a few minutes to read through this guide for useful information concerning the operation of your new preamplifier Once installed please allow an appropriate break in...

Страница 4: ...er 5 6 7 7 8 9 9 9 9 9 Operation Front Panel Controls and Display Start Up Shut Down Break in Front Panel Controls Remote Only Functions Settings Menu System Settings Menu Tree Settings Menu Auto Shut...

Страница 5: ...ontinued protection against fire hazard replace the fuse only with the same type and rating as specified at the fuse holder see page 19 for fuse information This unit is RoHS compliant The LS28 has au...

Страница 6: ...ns Installation Remove all screws fastening the top cover Carefully remove each vacuum tube from its protective foam and match its location V number written on the base of the tube to the V number pri...

Страница 7: ...enclosure such as an equipment rack make certain that adequate airflow above and to each side of the unit is provided Audio Research recommends a minimum of 6 8 inches 15 20 cm of clearance above the...

Страница 8: ...8 Connections Back Panel Connections Record Outputs Main Outputs RS 232 connector Control connections Fuse Holder A C Mains connector Single ended Inputs Balanced Inputs...

Страница 9: ...amplifier s and could cause serious serious damage to the amplifier s or loudspeakers A C Power Connection It is important that the LS28 be connected via its supplied 15 amp IEC 14 gauge power cord to...

Страница 10: ...10 Operation Front Panel Controls and Display Input Select Vacuum Fluorescent Display Volume Power On Off Menu Enter used with Menu Mono Stereo Invert Phase Mute...

Страница 11: ...OFF will flash on the display until the warm up cycle is complete Select input source and adjust the volume as necessary Shut Down Activate MUTE function Turn off power amplifier s Press Power switch...

Страница 12: ...preamp indicated by active display window The LS28 requires approximately 45 seconds to warm up this time is required to stabilize the vacuum tubes See Start Up Procedure on page 11 for details Menu...

Страница 13: ...f the eight inputs available on the LS28 Display Brightness Adjustment The front panel display has six brightness settings as well as the ability to dim the display completely To change the brightness...

Страница 14: ...14 Operation System Settings Menu Tree...

Страница 15: ...the front panel display Both the MENU and ENTER buttons found on the front panel and remote as well as the volume knob or the up down volume buttons on the remote are used to make changes to the menu...

Страница 16: ...the bottom line When using the input selected for processor mode note that in place of the volume number on the operation screen a pass through symbol will be shown Warning When processor mode is ass...

Страница 17: ...eset them to zero after a power off cycle When volume reset is set to OFF the LS28 will also remember settings after a power cycle To change the status of the volume reset press the MENU button until...

Страница 18: ...t Even with the power turned off a charge remains in the energy storage capacitors for hours or even days Cleaning To maintain the new appearance of this preamplifier occasionally wipe the front panel...

Страница 19: ...19...

Страница 20: ...the United States the authorized importing retailer or distributor has accepted the responsibility for warranty of Audio Research products sold by them The specific terms and remedies for fulfillment...

Страница 21: ...16V RMS BAL 8V RMS SE Rated Outputs 2V RMS 1V RMS SE into 200K ohm balanced load maximum balanced output capability is 17V RMS at less than 0 5 THD at 1kHz Crosstalk 105dB or better at 1kHz Controls R...

Страница 22: ...notice 2016 Audio Research Corporation Reproduction of this document in part or whole is expressly forbidden without written consent from Audio Research Corporation 3900 Annapolis Lane North Plymouth...

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