background image

5

Warnings

• To prevent fire, or shock hazard, do not 

expose your LS28 to rain or moisture.

• Do not place objects containing 

liquids on top of this unit.

• This unit contains voltages which can cause 

serious injury or death. Do not operate 

with covers removed. Refer servicing 

to your authorized Audio Research 

dealer or other qualified personnel.

• The detachable power cord on your 

LS28 is equipped with a heavy gauge, 

3-conductor cable and a standard three-

prong grounding plug.  For absolute 

protection, do not defeat the ground 

power plug. This provides power line 

grounding of the LS28 chassis to provide 

absolute protection from electrical shock.

• The appliance coupler (a.c. power 

connector) at the rear of this unit must be 

accessible for emergency power disconnect.

• The power button on the front of this 

unit, when off, does 

not

 disconnect 

all power from this unit. This unit is 

in sleep mode when not on. (In sleep 

mode, the tubes and audio circuit are 

powered off; the microprocessor that 

operates the LS28 remains on).

• For continued 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 automatic muting to help 

protect system components in the event 

of low line voltage. When sensing low line 

voltage, the preamp displays ‘Low Line’ 

and automatically goes into ‘Mute’. This 

condition will persist until the line voltage 

returns to a safe operating level; please 

note the unit will remain in ‘Mute’ even 

after ‘Low Line’ no longer appears.

• Note that automatic muting is only 

designed to protect against power line 

interruptions or severe voltage drop. It 

will not mute in the event of subsonic 

transmissions from a faulty input source, 

amplifier failure or speaker malfunction. 

A note about packaging... 

Save all packaging in a dry place away from 

fire hazard. Your LS28 preamplifier is a 

precision electronic instrument and should 

be properly cartoned any time shipment is 

made. You may not have occasion to return 

your unit to the factory for service, but if 

that should prove necessary, or another 

occasion requiring shipment occurs, the 

original packaging will protect your LS28 

from unnecessary damage or delay.

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...

Отзывы: