Can KEF 103/3 be driven with lower watt tube amp?

Discussion in 'Speakers' started by AmbientMan, Feb 10, 2019.

  1. AmbientMan

    AmbientMan New Member

    Messages:
    12
    Location:
    Hyattsville MD USA
    Considering on picking up a nice set of 103/3 that need no servicing, have the stands, and the correct Kube. The stated specs are 4 ohm/92 db efficiency. My 6.5 watt tube amp drives my Tekton speakers, that have exact same specs as the 103/3, with plenty of authority. In fact, I think the speakers probably reach their limits at about 12-1pm on the volume, at 100+ db peaks.

    Can I expect to drive the KEF the same way as the Tektons?

    TIA...
     

     

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  2. DOBIEGUY

    DOBIEGUY AK Subscriber Subscriber

    Messages:
    724
    Location:
    Woodhaven N.Y.
    I’ve owned my 103/3 since new. I use a 100watt Bryston and they have the ability to play extremely loud and clear.
    I don’t see your pair reaching their potential with 6.5 watts.
    Also, you wouldn’t want to jeopardize those difficult to find and expensive tweeters with an amp being overdriven.
     
    slimecity likes this.
  3. SaSi

    SaSi Seriously Illogical Subscriber

    Messages:
    4,205
    Location:
    Athens, Greece
    It totally depends on how loud you want to listen to. I'm currently listening to some background music and the VU meters on the amplifier peak at about 0.1W. Indeed, 6.5W won't get you much loudness, teenager party levels are absolutely out of the question, but chamber music and smooth jazz would be great.
     
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  4. savatage1973

    savatage1973 AK Subscriber Subscriber

    Messages:
    6,831
    Location:
    NW Pennsylvania snow belt
    "The cube" is inherently "parasitic"--just like the EQ's on Bose 901's. It extends the performance range basically beyond the "real" optimal capabilities of the drivers. I would think you would need far more "clean" power to drive them to the same levels.
     
    darkblue94 likes this.
  5. SaSi

    SaSi Seriously Illogical Subscriber

    Messages:
    4,205
    Location:
    Athens, Greece
    The argument that an equalizer before the loudspeaker (and amplifier) is parasitic is a big discussion. Loudspeakers are "systems" and it is widely accepted that a "parasitic" circuit, the crossover, is an integral part of any multi-way loudspeaker.

    In addition to loudspeaker alignments that are passively tuned, like the sealed enclosure or the ported enclosure, each with their "natural" cutoff slopes in the low frequencies that are reached by the interaction of the woofer properties and enclosure / port dimensions, there are "assisted" alignments that utilize active parts.

    My experience is with the KEF 107. The 4th order bandpass design utilizes a sealed rear chamber of relatively small size for a driver. The woofers in the KEF 107 could be optimally used in a sealed enclosure (1st order) of twice or three times the size.

    Because of the small enclosure in this design, the excursion of the woofer is much better controlled and through equalization, the low frequencies can be (carefully) augmented to achieve a much flatter response further lower in the frequency before the cuttoff. It is much better to equalize high the low frequencies you want to enhance rather than passively attenuate the higher low frequencies. A much lower power amplifier will be needed, no power will be lost in passive components and all becomes more feasible.

    I agree that all is highly unusual and not much exploited, but that doesn't mean it's wrong or useless.
     
  6. Hawkeye83

    Hawkeye83 AK Subscriber Subscriber

    Messages:
    1,976
    Location:
    East-Central Iowa
    My only experience with KEF's and tubes is the 103.2 and a small 6bq5 amplifier. Man, it sounded GREAT! BUT...in a nearfield set-up, and lower volumes. Best I've ever heard the 103.2's sound though. Today I'm going to receive some 90 wpc Quicksilver tube amps and try them out on the 103.2's and the 107's...although the amp was purchased mainly for my Tannoy Ardens...I'm going to rotate/experiment. Hoping to hear some more of that KEF/tube magic!
     
    darkblue94 likes this.

     

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