Cooked my cabinet

  • Hi, I've been running my powered Kemper thru my Matchless 4x10 cab and it shattered the voice coil of the first in line.. From what Christoph has said, 600watts digital equates to approx 100watts valve? My cab has 4 10 inch 30watt Greenbacks in it. So I've 120watts to play with.!! Would be great to know if I'm overpowering my cab. Been a very expensive venture. The couple of concerts I did prior to it blowing sounded amazing though. Cheers

  • First, as Lokasenna said, a Watt is a Watt. 600W into a 120W cab will fry it very quickly.
    What you're talking about is apparent loudness - and the ratio is roughly 1:4 and not 1:6.


    It might work if you don't crank it up and have good ventilation, but it's far from ideal.

    "But dignity is difficult to maintain
    stamina requires constant upkeep
    repetition is boring
    and you pay for grace."

  • From my reading on this website, you let the profile be the distortion. If you power amp kpa to a cab that is less that 600w, you need to make sure you aren't overdriving the speakers to distortion.


    Since the profile has the distortion, that wouldn't even sound good, I should think.


    That said, I've never had the privilege of killing a cab, unless it was wine.

  • There are two things a speaker does not like.


    a) a clipping (transistor) amp
    b) to much power for a longer time


    a) sounds very bad - and I hope there is protection to reduce power before dc comes out of the amp - which can kill a speaker very fast.
    Most home stereo system speakers get toasted by a amp with to little power - turned up to much until it clips - and then destroys the tweeter and if done for an extended time even more.


    b) If the amp is to powerful for your speakers (eg 600Watt is much to much for 100Watt speakers) - then should the amp not be cranked to much - or your speakers die because of to much heat.
    There is no protection for this possible (on the amp side) - just don't play this loud.


    And yes 1 Watt = 1 Watt regardless of tubes, classic transistor amps or modern class d.

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  • Hi, I've been running my powered Kemper thru my Matchless 4x10 cab and it shattered the voice coil of the first in line.. From what Christoph has said, 600watts digital equates to approx 100watts valve? My cab has 4 10 inch 30watt Greenbacks in it. So I've 120watts to play with.!! Would be great to know if I'm overpowering my cab. Been a very expensive venture. The couple of concerts I did prior to it blowing sounded amazing though. Cheers


    That is sad to hear.
    The others are right, Watt is Watt. The equation that it equates to 100 Watt is about the loudness that you can achieve. You need more potential Watt to achieve the same sound with a SS amp as you need to amplify it distortion-free, which is not the case on a tube amp, where soft distortion is even appreciated for compression and saturation.


    Let me ask some questions:


    -What is the Ohm of your 4x12 ?
    - What was the setting of your master volume or better: monitor volume and power amp boost?
    - Did you play clean or distorted sounds when your speaker blew?


    CK

  • sorry to hear this....either your speakers are weak, your volume is monstrous or I am just plain lucky. I blast through my Mesa 2x12 at insane levels at band practice with no issue....I should chill out on that I suppose


    If you're using highly distorted sounds, they are so compressed that you can achieve insane loudness without blasting speakers. If you go into less distorted territory though...watch out 8)

  • so far i just managed to blow something clean... well, you get the message. if i'm not mistaken, the poweramp-boost - if applied generously - is supposed to 'compress' your signal just a bit and therefore keep those cleanish speakerkillers down for just a bit longer...

  • yeah, sounds pretty counter-intuitive... maybe mothership could confirm, but as far as i unterstood, it boosts the perceived loudness, therefore reduces headroom
    -> reduced 'spikes'...


    good luck and please report back about the 2x12 option. if they come out with a vertical design, i'd buy it in a heartbeat...

  • Power Amp Booster
    As mentioned, the power amp is connected to the Monitor Output, which provides enough headroom to
    support even loud attacks and transients of clean guitars. However, this comfortable headroom will naturally
    lower the signal volume for the power amp, so you might not achieve the desired loudness. Turning
    up the Power Amp Booster will increase the loudness by up to 12 dB. Although this will shrink the headroom,
    this is no bad thing, as this happens in tube amps as well. Very loud signals and transients will then
    be compressed by a nice, organic-sounding soft-clipping circuit.


    When the power amp is switched off, the Power Amp Booster is deactivated, thus returning the full signal
    headroom to the monitor output.