A mongo sized amplifier is no insurance that your not going to push the amplifier to the point that you clip the darn thing. As we learned earlier the proper load is essential for any amplifier to work correctly. Never ask any amplifier to work a lower impedance load than what it was designed for. Ask your self if its really worth it to bridge an amplifier just to gain another 3db of output.
Meters and clipping circuits cannot respond fast enought. Meters especially cannot even hope to keep up. Circuits with Led's are certainly faster responding but unfortunately we the operators are not capable of seeing the response sometimes. I have been told that the led has to be on for a small period of time before our eyes can see and our brain respond and I believe this could very well be true.
While I refuse to depend on any meter or led in a circuit no matter how fast responding it may be I am a believer in adding a small light in series with the tweeter. I use this trick that I learned from Mr. DJK on this forum to help me make the professional sound systems that I work on nearly blow up proof. So far it has worked on everything I have adapted it to. I have installed a properly sized light bulb in a variety of different sized drivers and it works.
Unfortunately you cannot make everything idiot proof but it does seem to help.
Meters and clipping circuits cannot respond fast enought. Meters especially cannot even hope to keep up. Circuits with Led's are certainly faster responding but unfortunately we the operators are not capable of seeing the response sometimes. I have been told that the led has to be on for a small period of time before our eyes can see and our brain respond and I believe this could very well be true.
While I refuse to depend on any meter or led in a circuit no matter how fast responding it may be I am a believer in adding a small light in series with the tweeter. I use this trick that I learned from Mr. DJK on this forum to help me make the professional sound systems that I work on nearly blow up proof. So far it has worked on everything I have adapted it to. I have installed a properly sized light bulb in a variety of different sized drivers and it works.
Unfortunately you cannot make everything idiot proof but it does seem to help.
Little help is set up clipping indicator " below " real clipping ( 1-3 dB ), only for indication, that we are near " danderous " area....Indication must be extended,'cos eye have relative long reactive time.
also, one thing i see often here in the pro-audio business is UNDERPOWERED amplifiers taking out tweeters, because they are run constantly clipped, for several hours at a time......
also, one thing i see often here in the pro-audio business is UNDERPOWERED amplifiers taking out tweeters, because they are run constantly clipped, for several hours at a time......
Very good point...
What I fix and or put together is tri- amped. When I speak of pro-audio I'm talking the 50,000 watts of power on up for stadium systems.
Re: Re: Nad 2200 falling into protection, burning my tweeters.
I hope I am not too late here. It seems really weird to me that everyone is suggesting really ufo stuff like speaker cables to be at fault. C'mon!
First of all it seems really unlikely that you would have any problem in your amps since they both act the same and the odds are very small they both have the unique problem of frying the tweeters. And the same goes for the speakers, if one was broken how come all of them are frying. Not very likely is it.
Have you always used the same preamp, eq, and the music source when this frying happened?
So my point it that the amps and the speakers could be perfectly allright!
You see the real problem might be the equalizer, preamp or the music source (for example a cd player) that
is faulty and making(emitting) constant, very loud and very high frequency (like 22khz) that you cannot hear and it is killing the tweeters!
So if I were you I would take all of those devices off the system and loan your friends cd player and preamp for testing. And don't use any eq. Let us know how it works out!
Hemiguy said:
I hope I am not too late here. It seems really weird to me that everyone is suggesting really ufo stuff like speaker cables to be at fault. C'mon!
First of all it seems really unlikely that you would have any problem in your amps since they both act the same and the odds are very small they both have the unique problem of frying the tweeters. And the same goes for the speakers, if one was broken how come all of them are frying. Not very likely is it.
Have you always used the same preamp, eq, and the music source when this frying happened?
So my point it that the amps and the speakers could be perfectly allright!
You see the real problem might be the equalizer, preamp or the music source (for example a cd player) that
is faulty and making(emitting) constant, very loud and very high frequency (like 22khz) that you cannot hear and it is killing the tweeters!
So if I were you I would take all of those devices off the system and loan your friends cd player and preamp for testing. And don't use any eq. Let us know how it works out!
Re: Re: Re: Nad 2200 falling into protection, burning my tweeters.
Or did you forget to look at the thread before posting.
Dual said:
I hope I'm not included in "everyone".
Or did you forget to look at the thread before posting.
I hope I'm excluded as well...
However I hope and think that it was not Dual's intension to include everyone.
ultrasonic component?
I do recall that the amp has two sets of inputs, marked "normal" and "lab". Normal has bandpass filtering, but I can't remember where the hf rolloff occurs. It is intended to keep rf out of the input, more than ultrasonic audio, I suppose.
Do dogs howl before the tweeters smoke? (sorry)
I do recall that the amp has two sets of inputs, marked "normal" and "lab". Normal has bandpass filtering, but I can't remember where the hf rolloff occurs. It is intended to keep rf out of the input, more than ultrasonic audio, I suppose.
Do dogs howl before the tweeters smoke? (sorry)
Over Thinking the Issues
The amp is clipping! Clipping destroys tweeters!
Bridging hurts not helps the problem! Reduced load tolerance! More clipping!
KEF cubes add about 9DB of gain at 20HZ! Bringing the effective efficiency to 83DB! Adding to the clipping problem.
Add in a smiley face EQ! Adding to the clipping problem.
Just about any home amp will clip at very low apparent SPL's under these conditions.
The amp and speakers are both good products. However not for Mr. Hemi's needs. His needs just create the perfect storm as outlined above. I am surprised he didn't destroy the amps or more tweeters than he has.
Thanks, DonS
The amp is clipping! Clipping destroys tweeters!
Bridging hurts not helps the problem! Reduced load tolerance! More clipping!
KEF cubes add about 9DB of gain at 20HZ! Bringing the effective efficiency to 83DB! Adding to the clipping problem.
Add in a smiley face EQ! Adding to the clipping problem.
Just about any home amp will clip at very low apparent SPL's under these conditions.
The amp and speakers are both good products. However not for Mr. Hemi's needs. His needs just create the perfect storm as outlined above. I am surprised he didn't destroy the amps or more tweeters than he has.
Thanks, DonS
Just a thought, perhaps the input voltage (line input) is causing the preamp stages in the NAD to preclip before hitting the power amp stage. So the power amp is at volume 3 but it's being fed a square wave from the internal preamp.
Like for instance if the input stage has +3v, -3v rails and you're actual feeding it +-4v, (just an example). If you had the soft clipping circuit on the preamp portion then you'd see the clipping indicator at "volume 3" and while your not feeding huge amount of power the signal is more square wave causing harmonics to kill the tweeter.
Mind you, i don't have a lot of experience in amps, it's just a thought.
Like for instance if the input stage has +3v, -3v rails and you're actual feeding it +-4v, (just an example). If you had the soft clipping circuit on the preamp portion then you'd see the clipping indicator at "volume 3" and while your not feeding huge amount of power the signal is more square wave causing harmonics to kill the tweeter.
Mind you, i don't have a lot of experience in amps, it's just a thought.
Hemiguy said:
You may have checked this a long time ago but ..
See if the amp is putting out D/C voltage , a little is ok but if it makes like 1 volt dc you got a problem .
"You may have checked this a long time ago but ..
See if the amp is putting out D/C voltage , a little is ok but if it makes like 1 volt dc you got a problem ."
And how, pray tell, would that get past the crossover into the tweeter?
See if the amp is putting out D/C voltage , a little is ok but if it makes like 1 volt dc you got a problem ."
And how, pray tell, would that get past the crossover into the tweeter?
"the cap takes time to charge and that charge has to flow through the tweeter."
Meaningless.
Keele in Audio magazine tested routinely ran multi-KW tone bursts through 1" dome tweeters with no damage.
I did see some damage to Audax tweeters from 100V transients, but these were failures from lead-out wire metal fatigue (on tweeters having self-terminated leads). Tweeters with braided lead-outs did not fail.
Clipping (and large amplifiers) cause tweeter failures from too much long term average power. Mechanical damage from inexpensive lead-outs, 6dB crossovers, or too low of a crossover point, are the other cause of tweeter failure.
Meaningless.
Keele in Audio magazine tested routinely ran multi-KW tone bursts through 1" dome tweeters with no damage.
I did see some damage to Audax tweeters from 100V transients, but these were failures from lead-out wire metal fatigue (on tweeters having self-terminated leads). Tweeters with braided lead-outs did not fail.
Clipping (and large amplifiers) cause tweeter failures from too much long term average power. Mechanical damage from inexpensive lead-outs, 6dB crossovers, or too low of a crossover point, are the other cause of tweeter failure.
"meaningless"?
Why should you compare an AC signal to a DC step from 0Vdc to XXVdc.
When this happens the capacitor is charged from 0Vdc across it's plates to XXVdc across it's plates.
What is the route for that charge to get onto the cap?
Why should you compare an AC signal to a DC step from 0Vdc to XXVdc.
When this happens the capacitor is charged from 0Vdc across it's plates to XXVdc across it's plates.
What is the route for that charge to get onto the cap?
If you can play a squarewave of the same amplitude at low frequency (say 50Hz) into the (crossed over) speaker and the tweeter survives the transition from -(X/2)V to +(X/2)V just once it has passed the test.
KEF tweeters fragile? I have never heard such a weird statement. I had 104/2s for years and drove them very hard with a Quad 405-2 and that is an amp NAD could only dream of matching for quality.
I suggest you throw the NAD in the bin and get a decent amplifier mate!
I suggest you throw the NAD in the bin and get a decent amplifier mate!
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