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Can a AU-719 Drive KG-4 Speakers?

Discussion in 'Exclusively Sansui' started by 71R/T, Jan 2, 2018.

  1. 71R/T

    71R/T Member

    Messages:
    64
    Location:
    Triangle Area, NC
    I know this has been beat to death and I have read every post I can find including how 4 ohm loads stress an amp but I have yet to see the basic question answered and that is on the back of the amp it specifically states that when driving two pairs of speakers they must be 8 ohms or higher. So that would mean a 4 ohm load with two pairs of 8 ohm speakers in parallel. So why not a single pair of 4 ohm speakers? The KG-4 speakers are very efficient so they should not present a difficult load?
     

     

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  2. jameswei

    jameswei Super Member

    Messages:
    2,045
    Location:
    Taipei. Taiwan
    I have a pair of KEF 105/3 speakers that are rated @ 4 ohms and it's around 91DB sensitivity, all my Sansui amps drive it without any problem at all, from the lowly MOS607 Premium(45 watts) to the 200 watts B-2102, all without any issue. I am sure its fine with the KG-4.
     
    smurfer77 likes this.
  3. UncleBingo

    UncleBingo AK Subscriber Subscriber

    Messages:
    1,309
    An AU-719 in good repair should have no problem driving KG-4's. Just monitor the temperature every now and then. if it gets hot, shut it down.
     
  4. JOMARK911

    JOMARK911 Super Member

    Messages:
    2,538
    Location:
    Athens Greece
    If it gets hot put a pair of pc fans to suck the heat out of it. You're done.
     
  5. rasenthiran

    rasenthiran Well-Known Member

    Messages:
    759
    Location:
    Malaysia
    Hi Jomark,

    Is it safe to place a fan or blower at top of the amplifier for cooling purpose? I have come across few people saying it is not a good practice.
     
    Last edited: Jan 4, 2018
  6. ManyMoonsAudio

    ManyMoonsAudio AKA paul79 Sponsor Subscriber

    Messages:
    3,064
    Location:
    Tulsa Ok (C-Ville)
    I wouldn't put fans on any amplifier. They are typically made to regulate themselves with regards to temperature change. Putting fans on them is not a good idea.

    The only place to use a fan is if you have the amp in a cabinet where it cannot get good natural airflow. In this case, I would put a quiet fan in the back of the cabinet, pulling air out of the cabinet space. Better yet, let the amp be its own entity, display it proudly out in the open where it can breath, and it will take care of itself.
     
    Hipocrates likes this.

     

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  7. gregmcm

    gregmcm AK Subscriber Subscriber

    Messages:
    198
    Location:
    Toronto, Canada
    rasen, you might want to have a look at this thread I was part of with regards to ventilation for a Pioneer unit I have in a stack. Once on the thread the discussion regarding ventilation starts about half way down the first page. http://audiokarma.org/forums/index.php?threads/sx980-stereo-decoder-chip-advice.798266/
     
    rasenthiran likes this.
  8. Blue Shadow

    Blue Shadow I gotta get me a new title

    Messages:
    21,477
    Location:
    SE PA
    If folks are going to fall for that line of hyperbole, then just turning on the amp will stress it. Almost everything from the golden years, 72-83 was able to drive a 4 ohm load unless it is mentioned in the documents or the back of the unit that it is not. The use of any speaker with an amplifier will stress it, causing actual electricity to move through its circuits. Something it was designed to do but over time it takes its toll and some parts might wear out. Sure a 4 ohm load will cause the amp to send more current to the speakers which means that current is also flowing through the amp but stressing the amp, not at normal listening levels. Amps are designed to get warm/hot, many having thermal cutoffs built in. Used that feature many times. Amps just fine following this. They were designed for this. Not all amps have this so see how hot it gets when you are really cranking tunes and if it is hot fine, if it is very hot, find out what temp that is and post it. I have an amp that runs at 130°F at idle and it is not class a which runs hot at idle. I hope folks would not be concerned about that crap about 4Ω stresses amps, hell 100 mph stresses cars but they can still go significantly faster and they were designed to do it. Unfortunately the drivers were not designed or trained to do it.
     
    Last edited: Jan 4, 2018
    gregmcm likes this.
  9. rasenthiran

    rasenthiran Well-Known Member

    Messages:
    759
    Location:
    Malaysia
    Thanks Greg,will have a look on the thread.
     
  10. JOMARK911

    JOMARK911 Super Member

    Messages:
    2,538
    Location:
    Athens Greece
    Well you should be here in Greece last summer. 30-35c indoor , and feel B2301 B2302 AUX911DG's ,getting real HOT, while idling. Only the top cover was about 55c , just imagine what kind of temps where running in heat sink and the output devices. I don't want my amps, pcb's and their components getting that hot.
    A set of some fan's regulated to gently suck some of the extra heat increasing the natural circulation of air is not a bad thing.
    As far Rasenthiran's 717 driving 4ohms speakers , this is the same story. Suck some heat out of the box. Help natural circulation. No big deal. I'm not talking some fans pushing full cold air into the amp. Just a gentle suck of hot air . That's all.
     
    Hyperion likes this.

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