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#162466 - 04/01/07 05:22 PM
Re: Emotiva MPS-1 shutting down? Amp gurus help
[Re: PorterPlex]
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connoisseur
Registered: 07/23/04
Posts: 3739
Loc: Up yonder
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Why you guys are getting all worked up over decibel levels is baffling to me. That is irrelevant to what’s happening. The amps or part of the assembly is defective. Send them back or get your money back. If the amp is rated for a continuous 4 ohm load, and it shuts down driving a 4 ohm load, something is wrong with the speaker (short to ground), something is wrong with the amp, or the manufacture fudged their numbers. They should not be going into over current protection driving M80’s. Drivers are not some sort of mystical electron vacuum that sucks more current out of an amp that it is designed and rated to supply. They only draw available max current supply of the connected amplifier’s transformer, which your amps are not supplying without shutting down.
The simply fact that your Denon did not shut down should tell you something.
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"......The wisdom of life consists in the elimination of nonessentials." ~ Lin Yutang
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#162467 - 04/01/07 05:51 PM
Re: Emotiva MPS-1 shutting down? Amp gurus help
[Re: michael_d]
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shareholder in the making
Registered: 01/29/04
Posts: 13161
Loc: Iowa
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Not sure why you think we are getting worked up, we are simply using our findings to prove that we are not reaching the limits of the amps. Isn't that what AV people do?
If you read above, the company has already stated they realize there is an issue, that is why they have been working with me by next day shipping other amps to resolve my issue. I've talked to them on numerous occasions and am very impressed with their service.
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M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700 M22-OWM22-VP100-Denon2805 Audio Nirvana
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#162471 - 04/02/07 06:18 PM
Re: Emotiva MPS-1 shutting down? Amp gurus help
[Re: PorterPlex]
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shareholder in the making
Registered: 01/29/04
Posts: 13161
Loc: Iowa
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Update: Well I worked with Emotiva today over the phone. For starters, they went out and purchased a Radio Shack Analog meter like mine. In their labs they use much higher quality test equipment, for example, "Audio Toolbox" meters. This way they could try to recreate what I was seeing on my meter.
Anyway, their initial findings was that the amp was truely meeting the specs of 300 watts into 4 ohms, in fact, it was actually reading 380 watts when the amp protection kicked in.
Another finding, was that the Radio Shack meter is great for calibration of speakers, but not really the best for lab test readings. During the dynamic parts of songs where the RS meter would jump from 110dB to 115 or 116dB, their more accurate Audio Toolbox meters were showing 20+dB jumps.
Now, the conversation moved onto the amps Wave Form Limiter? I really didn't understand what this does, but it sounds like this was the main reason the amps are shutting down. Emotiva mentioned the amps will do 780 watts RMS no problem, from past tests in the lab, however, I believe this Wave Form Limiter protection restricts what gets passed onto the speakers?
I talked to Axiom, and was told the 80's have been run for 2weeks straight at 24hrs a day at 700 watts continuous with peaks reaching 1100 watts, while testing the new amp line. So I know the Axioms can handle the wattage.
Resolution:
Emotiva showed me with very detailed instructions/pictures how to remove one of the resisters which gives the Wave Form Limiter its input signal. I"m not worried about making this modification, as I've worked a little on circuit boards/soldering, etc.. Basically it just involves removing this resister with some small snips, no problem.
The tests Emotiva did today, showed that with the amps being pushed very hard, they will produce just over 1KW. The Resistor being removed is where the Wave Form limiter gets it’s input signal from. Now by removing it, this will disable the limiter whereby making the amplifier like most amps on the market today. The amp is still a dual tracking class H design and the protection circuit is still in place, only the limiter has been disabled.
Without the limiter it is possible to get out peaks in excess of 1KW if pushed hard enough which would easily toast most speakers. I would not recommend this modification if your not having a problem, and would contact Emotiva if you are...
Randy
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M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700 M22-OWM22-VP100-Denon2805 Audio Nirvana
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