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MANUAL AND AUTOMATIC TURN ON-OFF OPTIONS

7

YOU SHOULD KNOW
Turn Off Delay in the Audio Mode

When the music (audio signal) stops, the A 21 will remain turned on for about five minutes. 

This delay prevents unwanted turn-off during silent passages in music or pauses between 

1

Switch in up position

Start Sensitivity at 12 o'clock

You can manually turn the A 21 on and off with its front panel On-Off button. It can also be 

triggered  to  turn  on  and  off  automatically  when  your  preamplifier,  surround  controller,  or 

system controller is turned on and off. 

Manual On-Off from the Front Panel

 

 

If you want to manually turn on and off the A 21 at any time, you need to first select  

 

the Manual On-Off option by placing the 

Auto Turn On

 switch (on the rear panel) to 

 

its middle 

Man

 (Manual) position. 

Connecting an Active Audio Source for Automatic On-Off 

 

 

If you want to automatically turn on the A 21 whenever music is playing (an audio 

 

signal is present), choose the audio triggering option by moving the 

Auto Turn On

 

 

switch to its upper 

Audio

 position.

What You’ll Need:

    

    

•   An audio source that's playing

Before Connecting

 

 

Remove power to all the components in your audio system.

 

Make sure the 

Auto Turn On

 switch on the A 21 is in its 

Audio 

(up) position.

 

Set the 

Audio

 triggering 

Sensitivity

 adjustment knob on the rear panel to the desired 

 

level. Start with the 12 o’clock position. 

To Connect

    

    

Connect an active audio source to either the 

Left

 or 

Right Balanced

 or 

Unbalanced   

    

Input

 jacks. (Refer to to pages 2 and 3).

Содержание Halo A 21

Страница 1: ...A 21 Amplifier Owner s Guide...

Страница 2: ...u are unpacking your new amplifier inspect it thoroughly for possible shipping damage If you see any contact your Parasound dealer right away Be sure to save and store both the inner and outer cartons...

Страница 3: ...NAL DC SOURCE FOR A 21 AUTOMATIC TURN ON OFF _________________________________________________________________________________ CONNECTING THE A 21 TO TRIGGER ANOTHER COMPONENT ________________________...

Страница 4: ...rackets provided With its four feet removed the A 21 chassis and front panel height occupies four rack spaces 7 or 176 mm When mounting equipment below the A 21 you will also need to allow about 1 8 b...

Страница 5: ...that you connect them to these inputs Refer to the Balanced and Unbalanced Lines in the Technically Speaking section for additional information about why we recommend using balanced lines What You ll...

Страница 6: ...e Ground switch is in its Normal down position To Connect Plug one end of the cable into the Unbalanced Right Channel Input jack on the A 21 Plug the other end of this cable into the unbalanced right...

Страница 7: ...ed or stretched once they are connected To Connect Plug one end of the cable to the right channel Loop Out jack on the A 21 Plug the other end of this cable to the right channel input jack on the othe...

Страница 8: ...lack Right negative speaker terminal on the A 21 Insert the other end of the wire with the ridge or other marking into the red right positive terminal on the speaker Insert the wire without the ridge...

Страница 9: ...th an impedance of 8 or higher Before Connecting Remove power to all the components in your audio system Set the A 21 Stereo Mono Bridge Switch to its Mono up position To Connect From the Source Plug...

Страница 10: ...ou need to first select the Manual On Off option by placing the Auto Turn On switch on the rear panel to its middle Man Manual position Connecting an Active Audio Source for Automatic On Off If you wa...

Страница 11: ...utomatically turn on and off the A 21 with an external DC voltage choose the DC Triggering option by moving the Auto Turn On switch on the rear panel to its lower 12V position What You ll Need A cable...

Страница 12: ...matically there is 12 Vdc present at its own DC Trigger Out jack so it can trigger additional amplifiers or other components on and off What You ll Need A cable with a 2 5 mm sub mini plug on each end...

Страница 13: ...oblem Please contact Parasound s Technical Service Department Left and Right Channel Status Indicators These are two small round indicators in the center of the recess in the front panel The indicator...

Страница 14: ...oltage for your unit is marked on its carton Changing the A 21 s operating voltage involves rewiring internal connections for both its main power transformer and standby power transformer plus changin...

Страница 15: ...able parts inside To avoid the risk of electric shock do not remove its top cover The amplifier s exterior can easily be cleaned with a soft cloth pre moistened only with a few drops of water or glass...

Страница 16: ...Mono Bridge switch is in the Mono bridged position Damaged speaker Move to the correct position for the jack in use Balanced Unbalanced Input switch is in the incorrect position Not enough ventilation...

Страница 17: ...cept any of the following Units with collect shipping charges Units without a valid RA number Units without a suitable shipping carton Units for which we see or hear evidence of improper packing For a...

Страница 18: ...ive signals For example when a 1 Volt signal arrives at a balanced input stage the differential input sees a positive 1 Volt minus a negative 1 Volt or 2 Volts total External hum and noise that someho...

Страница 19: ...This separates the A 21 s signal input ground from its chassis ground to isolate unwanted voltage in the ground shield of the unbalanced RCA input cable Be sure your system installation is finished b...

Страница 20: ...o drive the MOSFET drivers in the following stage Circuit designed by John Curl Parasound design consultant John Curl has been a legend among audiophiles and electronic engineers for decades He pionee...

Страница 21: ...these fuses halt operation to minimize damage to additional parts The Driver Stage The driver stage provides critical amplification for which we employ a complementary matched pair of MOSFETs selected...

Страница 22: ...ced 66 k Input Sensitivity for 28 28 V Output into 8 Unbalanced 1 V Balanced 1 V per leg Features and specifications subject to change without notice Loop Output Level Same as input level S N Ratio 11...

Страница 23: ...Parasound Products Inc 950 Battery Street San Francisco CA 94111 415 397 7100 Fax 415 397 0144 www parasound com...

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