A guy I know has a Parasound HCA-2200 11 amplifier driving a pair of Polk speakers. This guy has taken out several pair of tweeters in short time.
I believe the guy is clipping the amp and this is why the tweeters are being taken out. Other people are telling me there is a problem with the amplifier.
Anyone have any ideas/ suggestions?
I believe the guy is clipping the amp and this is why the tweeters are being taken out. Other people are telling me there is a problem with the amplifier.
Anyone have any ideas/ suggestions?
Hi Joe,
I'm with you, clipping would be my guess. We did warranty service for Polk and also found their tweeters didn't take that much abuse to go open.
It is possible for amplifiers to oscillate, also the signal source. It's always wise to check everything. Let me know what you find out.
Just curious, what makes the other people so sure it's the amp? To finish that argument, just hang a 'scope on the output.
-Chris
I'm with you, clipping would be my guess. We did warranty service for Polk and also found their tweeters didn't take that much abuse to go open.
It is possible for amplifiers to oscillate, also the signal source. It's always wise to check everything. Let me know what you find out.
Just curious, what makes the other people so sure it's the amp? To finish that argument, just hang a 'scope on the output.
-Chris
Hi Joe,
I'm guessing the light bulb fix was not a factory authorized modification.
A fool and his tweeters are soon parted. Anyway, both tweeters would normally point to clipping. I'd still hang a 'scope on the output. Everything else is pure conjecture. Well, maybe a theory, or educated guess in this case. Best to rule out system issues before you end up with egg on your face.
-Chris
I'm guessing the light bulb fix was not a factory authorized modification.
A fool and his tweeters are soon parted. Anyway, both tweeters would normally point to clipping. I'd still hang a 'scope on the output. Everything else is pure conjecture. Well, maybe a theory, or educated guess in this case. Best to rule out system issues before you end up with egg on your face.
-Chris
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Hi jleaman,
No, as the average current rises, the resistance of the bulb goes up. Mind that the bulb also has an inductive characteristic. These bulbs are great for the warranty program. Good for tweeters, but not exactly hi fi. This will also change the crossover frequency (load resistance is changing).
The speakers appear to become more bass heavy as the tunes get cranked.
-Chris
No, as the average current rises, the resistance of the bulb goes up. Mind that the bulb also has an inductive characteristic. These bulbs are great for the warranty program. Good for tweeters, but not exactly hi fi. This will also change the crossover frequency (load resistance is changing).
The speakers appear to become more bass heavy as the tunes get cranked.
-Chris
Chris,
I have always used the bulbs in series with the hot leg. Mainly in commercial applications I use a tail light bulb. It turns on at 60 watts so no more power goes to the driver. I have done frequency sweeps both with and without the bulb and the response is the same.
From the standpoint that no more high frequency material is passed when the bulb turns on I will have to agree with you.
There are other manufacturers that use bulbs as standard equipment in their speakers.
Not a bad fix when your going to beat the sh*t out of things.
I have always used the bulbs in series with the hot leg. Mainly in commercial applications I use a tail light bulb. It turns on at 60 watts so no more power goes to the driver. I have done frequency sweeps both with and without the bulb and the response is the same.
From the standpoint that no more high frequency material is passed when the bulb turns on I will have to agree with you.
There are other manufacturers that use bulbs as standard equipment in their speakers.
Not a bad fix when your going to beat the sh*t out of things.
Hi Joe,
I agree in a non-home enviroment. When the job is not professional and the tunes are cranked, a light bulb keeps the crowd dancing.
There are times when you can't win with a customer at home. Light bulbs installed for those individuals. What else can you do?
Still, you normally only bake tweeters when you clip the amp.
-Chris
I agree in a non-home enviroment. When the job is not professional and the tunes are cranked, a light bulb keeps the crowd dancing.
There are times when you can't win with a customer at home. Light bulbs installed for those individuals. What else can you do?
Still, you normally only bake tweeters when you clip the amp.
-Chris
We use limiters in professional applications and they work quite well. In addition to limiters there are occasions where extra measures need to be taken and that is where the light bulbs come into play.
It is unfortunate that the average home user cannot use logic to govern their judgement. The outcome of course is broken devices.
Many tweeters, midranges and woofers will suffer as a result.
It is unfortunate that the average home user cannot use logic to govern their judgement. The outcome of course is broken devices.
Many tweeters, midranges and woofers will suffer as a result.
Hi Joe,
So are you going to have a look at his system? Take the scope to the amp if you can to watch things in their natural enviroment. I want to hear you tell him "I told you so".
-Chris
Exactly! But your friend's system is not actively crossed over.
Home users are always confused between warranty and insurance programs. We all pay more because of this.
So are you going to have a look at his system? Take the scope to the amp if you can to watch things in their natural enviroment. I want to hear you tell him "I told you so".
-Chris
burnedfingers said:
I would measure output by oscilloscope, with speakers connected and some signal at the input of the amp. The situation looks like ultrasound or HF oscillations, probably the amp is unstable with some kind of load. Ultrasound/HF oscillations can destroy tweeters very quickly. They can appear only at some volume level, most likely at the point of classA to B transition with class AB amp.
Hi Joe,
What sound did the pie make as it landed? You may need to stand by the preamp with a bat to correct this behaviour.
Hi John,
I am thinking strongly of user error here. If Joe hung a 'scope on the outputs and didn't see any fuzz, it's not an HF oscillation problem. Of course there is no real harm in contacting the factory either, unless high toll charges occur.
-Chris
What sound did the pie make as it landed?
You may need to stand by the preamp with a bat to correct this behaviour.Hi John,
I am thinking strongly of user error here. If Joe hung a 'scope on the outputs and didn't see any fuzz, it's not an HF oscillation problem. Of course there is no real harm in contacting the factory either, unless high toll charges occur.
-Chris
Chris,
Logic seems to have gone to the way side when it comes to operation of audio equipment. The common idea seems to be that if you purchase a high dollar preamp it certainly will not clip nor will it provide too much signal to the amplifier.
John,
I certainly didn't mean to sound like I was slinging mud at the amplifier.
Quote:
HCA-2200II ULTRA HIGH CURRENT AMPLIFIER. Our premiere amplifier created by legendary designer John Curl has been called by "Stereophile," a benchmark product against which other amplifiers can be measured."
Thats one hell of a write up.
I am however dissapointed with your response pointing me to Tony even after I mentioned that there isn't a problem with the amplifier. I certainly hope I don't have to assume that you are in the same class as the great J. B of the noted SAE fame.
Logic seems to have gone to the way side when it comes to operation of audio equipment. The common idea seems to be that if you purchase a high dollar preamp it certainly will not clip nor will it provide too much signal to the amplifier.
John,
I certainly didn't mean to sound like I was slinging mud at the amplifier.
Quote:
HCA-2200II ULTRA HIGH CURRENT AMPLIFIER. Our premiere amplifier created by legendary designer John Curl has been called by "Stereophile," a benchmark product against which other amplifiers can be measured."
Thats one hell of a write up.
I am however dissapointed with your response pointing me to Tony even after I mentioned that there isn't a problem with the amplifier. I certainly hope I don't have to assume that you are in the same class as the great J. B of the noted SAE fame.
Hi Pavel,
Why would you expect that to be true in general?
I have never seen high quality inexpensive things, but I have seen some really well made, well designed expensive things. One thing for sure, if you don't pay the price you do not get quality. Of course, there is no guarantee of getting quality just because something is expensive.
Ever price art?
-Chris
Why would you expect that to be true in general?
I have never seen high quality inexpensive things, but I have seen some really well made, well designed expensive things. One thing for sure, if you don't pay the price you do not get quality. Of course, there is no guarantee of getting quality just because something is expensive.
Ever price art?
-Chris
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