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7

Installation

In your system 

• To ensure normal component life and 

safe operation this unit must be operated 

only in an upright position.  Adequate 

airflow and proper cooling can occur 

only if there is no restriction above and 

behind the unit and on either side. 

• The special non-marring elastomer feet 

provide adequate spacing and stability 

only on a smooth, hard surface, and also 

assist to isolate the preamplifier from 

spurious vibrations. For upright stability 

and best performance, never operate 

the unit while it is sitting on a soft 

surface such as a thick rug or carpet.

• Due to its weight, this preamplifier must 

be supported on a surface specifically 

rated for such a load.  Check with the 

manufacturer of your support system to 

be sure it is rated to handle this weight.

• If the unit is to be operated in an 

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 LS28 to maintain 

proper ambient operating temperature.

• The ‘ambient’ operating temperature 

should never exceed 30° C, 86° F. 

Improper installation will cause premature 

tube failure and will affect your warranty, 

as well as the service life of the unit.

• It is normal for a vacuum tube preamplifier 

to run quite warm, and if used for 

prolonged periods, hot to the touch. All 

components within are operated at safe, 

conservative levels well within tolerances.

A Note about Vacuum Tubes

The vacuum tubes in your LS28 have 

been burned in, tested and electrically 

matched to provide the best performance 

and reliability of your preamplifier. That 

said, vacuum tubes must be replaced 

from time to time. The 6H30 tubes in 

the LS28 should have an expected life 

of approximately 4,000 hours. This 

life expectancy is only approximate. 

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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