[Dan Banquer]

The analysis is fine Kevin, but I am not convinced that all voice coils meet your criteria.
So I will err on the side of caution here. The faster the protection works, the better.

[Kevin Haskins]

The analysis is fine Kevin, but I am not convinced that all voice coils meet your criteria.
So I will err on the side of caution here. The faster the protection works, the better.

I'm a pragmatic guy... I test it on actual woofers.      I don't use 80V rails but it works on 1" dome tweeters.   I have a 4" full range driver with a 0.75" coil and you can have a full rail voltage on it for about one thousand one, one thousand two... POOF!    Twenty milliseconds is plenty quick for any midrange or midwoofer.   

[Dan Banquer]

I'm a pragmatic guy... I test it on actual woofers.      I don't use 80V rails but it works on 1" dome tweeters.   I have a 4" full range driver with a 0.75" coil and you can have a full rail voltage on it for about one thousand one, one thousand two... POOF!    Twenty milliseconds is plenty quick for any midrange or midwoofer.

Well Kevin I am certainly impressed with your example, but I wouldn't want to bet the farm that many consumer audio woofers would do as well.
Like I said, I will err on the side of caution.
Regards;
    Dan Banquer

[Kevin Haskins]

Well Kevin I am certainly impressed with your example, but I wouldn't want to bet the farm that many consumer audio woofers would do as well.
Like I said, I will err on the side of caution.
Regards;
    Dan Banquer

I've not measured a time constant so I don't know actually how quick they are operating.  It may be that they are much quicker than 20mS.    All I really care about with my particular amplifier is that it is quick enough not to damage a tweeter.    Since all tweeters will have a cap on them you really have to concern yourself with the midwoofers and their power handling is magnitudes higher than a 4-ohm nominal tweeter.   I'm quite sure it could blow a ribbon tweeter.   I've popped a ribbon tweeter with a test signal getting a FR measurement.    You have to measure the things with a cap on them otherwise they become X-mas tree tinsel.    In loudspeaker designs though it is safe to assume that all ribbon tweeters will have a cap on them.   

[Dan Banquer]

I've not measured a time constant so I don't know actually how quick they are operating.  It may be that they are much quicker than 20mS.    All I really care about with my particular amplifier is that it is quick enough not to damage a tweeter.    Since all tweeters will have a cap on them you really have to concern yourself with the midwoofers and their power handling is magnitudes higher than a 4-ohm nominal tweeter.   I'm quite sure it could blow a ribbon tweeter.   I've popped a ribbon tweeter with a test signal getting a FR measurement.    You have to measure the things with a cap on them otherwise they become X-mas tree tinsel.    In loudspeaker designs though it is safe to assume that all ribbon tweeters will have a cap on them.   

I have found that relay time constants have a good amount of variation.
I used an Omron 12 volt PC mount in the SCPA 1 and found that some latched at 8 volts, some at 9 volts and some at 11 volts.
Are we having fun yet?
Regards;
   Dan Banquer

[FullRangeMan]

Hi,
Thinking about the equips failures I have in the past, I see they was four, three in the power amp and one in a preamp, and the fuses and other protections do dot save me at all !!
Here are the events:
1 - When turn on the power amp I do not heard the usual click and the amp dead, the power-on 15ampere swith broke.
2 - In early 1990years, when listen the fateful Klaus Schulze Dig It CD in hi SPL in the power amp stop. An output transistor blows.  http://www.amazon.com/Dig-Klaus-Schulze/dp/B0007ZBG2Y/ref=sr_1_1?ie=UTF8&s=music&qid=1266424703&sr=1-1
3 - In 2005 again in this same KS Dig It CD in hi SPL a Diode in the amp dead.
4 - Late 1980years a bad Diode in a preamp under warranty was alterated.
I think these NVA amps have smell of real Hi-End music at a affordable price, IF they had Class A output surely they would be a real competitor to the stratospheric FM Acoustics amps, that are ugly looking amps, and the NVA amps have a very discreet and beautiful looking.

[turkey]

Hi,
Thinking about the equips failures I have in the past, I see they was four, three in the power amp and one in a preamp, and the fuses and other protections do dot save me at all !!
Here are the events:
1 - When turn on the power amp I do not heard the usual click and the amp dead, the power-on 15ampere swith broke.
2 - In early 1990years, when listen the fateful Klaus Schulze Dig It CD in hi SPL in the power amp stop. An output transistor blows.  http://www.amazon.com/Dig-Klaus-Schulze/dp/B0007ZBG2Y/ref=sr_1_1?ie=UTF8&s=music&qid=1266424703&sr=1-1
3 - In 2005 again in this same KS Dig It CD in hi SPL a Diode in the amp dead.
4 - Late 1980years a bad Diode in a preamp under warranty was alterated.
I think these NVA amps have smell of real Hi-End music at a affordable price, IF they had Class A output surely they would be a real competitor to the stratospheric FM Acoustics amps, that are ugly looking amps, and the NVA amps have a very discreet and beautiful looking.

You don't say that you had a fire or blown speakers, so I guess the protection circuitry worked. (I don't know what amp and preamp you were using in the past, but I bet you will lose speakers or have a fire in the future if you buy an NVA amp.)

[FullRangeMan]

You don't say that you had a fire or blown speakers, so I guess the protection circuitry worked. (I don't know what amp and preamp you were using in the past, but I bet you will lose speakers or have a fire in the future if you buy an NVA amp.)

Hi,
I have no fire, blow VC speaker or blow amp fuse in this four problems. I never see a fire in a amp, even when I work in pro audio.
Iam surprised folks have a amp on fire.