Wow - what on earth is your application for that level of power?
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Buckeye Nc502mp Review (6 Channel Amplifer)
- Thread starter amirm
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If you are asking whether the vendor's amp can make the Hypex spec., ask them. Testing a kilowatt of output requires dummy loads that will take the heat. I can do but do not have either vendor's amp on hand and my NC502MP is an older version. It is important to understand Hypex's rating and conditions. Here is the Power vs SINAD graph from the data sheet...
So, with proper heatsinking, expect that a bridged NC502MP will deliver about 900 watts into 4 ohm at clipping . This is peak output at 1 kHz. As shown, the output is lower at 100 Hz. For fairness, is essential to compare to other amps under the same conditions. In more recent tests. Amir measures more comprehensively. For example...
So, can see why it is important to not only cite a power rating, but the conditions as well.
livinon2wheels
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I believe having the power reserves to reproduce 115 db peaks is essential to realistic presentation of either live rock and roll or dynamic movie soundtracks. That said, my normal listening level never approaches needing that level of power but I look at this whole business of sound reproduction at home possibly differently than most. Too much amplifier power for the expected need covers your butt when you accidentally exceed the ability of a lower powered amplifier and are presented with clipping distortion...and when that clipping distortion takes out a tweeter or a pair of them, then your system is down until you can get those tweeters replaced. Reliability is for me an absolute requirement. I don't want any hassle from the system I can avoid by thinking about and resolving potential problems before they happen. Therefore, buy more amplifier than you will need upfront. The amp will last longer due to less thermal stress, the speakers longer from never being exposed to a clipped signal, and I will be happier due to having a better performing system overall with reliability as part of the design goal. I know there are those that will be naysayers about this, but my experience has always been that more power than necessary is a good thing. I have never killed a speaker with too much power but I have done so several times with too little. This hobby is expensive enough without having to replace parts needlessly.
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Bridging is somewhat counterintuitive to this point. You will be putting more thermal stress on a bridged NC502MP then unbridged.
I read this as you aren't as concerned about the sustained long term output or heat, but more of the "driving it hard" with music dynamic output and heat. There is a big difference in the two. I wouldn't want to put any amp in a max continuous output for many hours, it's just not practical.
I have a Buckeye NC502 that is in a recording studio control room. The studio is used almost every day and many days for 8+ hours. Musicians drive amps hard, very hard with playback levels higher than most people would ever do in their homes.
The amp gets hot, but not uncomfortably hot, and has been in use for almost two years now with no ill effects. The only problem we've had with the amp is the "auto sensing" of the input failed. The auto sensing automatically turns the amp on when it sees a signal. That was repaired with no problems and I don't believe that was related to heat and certainly not to output levels.
I know that's not a definitive test and is more of "my experience," but it's all I got.
NOTE: Dylan was extremely responsive and provided parts for the input sensing repair at no cost even though the amp was slightly out of warranty. I can't say enough good things about Dylan and Buckeye amps!
livinon2wheels
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that is pretty rough noise characteristics at higher frequencies...ugh. Part of my thinking is if you want class D to be really clean, double the power rating of the amp that you buy. If 100 watts of clean class AB is what you need then buy 200 watts of class D and you'll get 100 clean watts of clean power with a bit of headroom.
livinon2wheels
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Please explain why this is so...if both channels on the board are active, what practical difference does it make if the module is running in bridged mode or stereo?
livinon2wheels
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I sense that there might be a misunderstanding of my meaning...if you buy an amplifier of a higher rated power than needed, particularly in class D, then you remove mostly the possibility of the amp being overdriven and as a plus you get lower distortion with extra power reserves. This should translate into less stress on the circuitry from not being used near its limits, as well as better performance. If properly designed it I would think it would run cooler than a smaller amp pushed harder. Clearly, the curves I have seen of class D amps show a linear rise in heat generated with increasing output for a given module...and I would think keeping that internal heat on the low end of the tolerable range would be in the best interest of long term reliability. So yeah I am considering both the effects of day to day usage where the equipment gets heat cycled and perhaps runs hot while it is powered up and then cools down repeatedly. The more extreme the difference between operating temperature and temperature at rest, the more thermal stress is applied to the components, solder joints and the like and the shorter the long term life. I appreciate your description of what you have seen personally and that is a good data point and gives me some idea of what I can expect. I look at longevity as an important factor for consideration. My expectation is a minimum of 10 years life for any piece of audio gear I buy with zero issues. Much of what I have owned in my life has lived up to that standard and I see no reason going forward to relax that requirement. I do wonder about the truly long term reliability of class d but consider it to be a reasonable risk or at least worth dipping my toe in the water and trying one out to see how it is to live with before committing wholesale to the technology. If I find them to be as good as many say, I'll be buying several of them over the next year or so.I read this as you aren't as concerned about the sustained long term output or heat, but more of the "driving it hard" with music dynamic output and heat. There is a big difference in the two. I wouldn't want to put any amp in a max continuous output for many hours, it's just not practical.
I have a Buckeye NC502 that is in a recording studio control room. The studio is used almost every day and many days for 8+ hours. Musicians drive amps hard, very hard with playback levels higher than most people would ever do in their homes.
The amp gets hot, but not uncomfortably hot, and has been in use for almost two years now with no ill effects. The only problem we've had with the amp is the "auto sensing" of the input failed. The auto sensing automatically turns the amp on when it sees a signal. That was repaired with no problems and I don't believe that was related to heat and certainly not to output levels.
I know that's not a definitive test and is more of "my experience," but it's all I got.
NOTE: Dylan was extremely responsive and provided parts for the input sensing repair at no cost even though the amp was slightly out of warranty. I can't say enough good things about Dylan and Buckeye amps!
Maybe but you'll spend more for quality Class AB and still may have challenges at some frequencies. Would not trust gross generalizations when I have real measurements to compare. Here is another Class D (note edit per later post) design (almost $10K) that Amir recently tested...
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Bridging cuts the impedance seen by each channel in half, which increases the current for a given voltage. More current = more heat. 8-ohm speakers draw from the bridged amp like 4-ohm speakers from an unbridged channel. The 502 is rated for 4-ohm speakers when bridged and 2 ohms unbridged, but be sure they are really 4-ohm speakers. My Advent NLA from the old days, for example, are rated at 8 ohms but dip to less than four ohms in one spot on the spectrum. They would pose a problem for many amps when wired in parallel (which was a thing in the day with Advents).
Rick "same effect as wiring speakers in parallel" Denney
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Was just replying but Rick said it perfectly.
It's also why Hypex discourages pairing a 4ohm speaker to a BRIDGED 502MP module.
It can be done (and has without issue) but only if you really know the speaker isn't dipping under 4ohm.
livinon2wheels
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@Rick Sykora - Thanks for posting that graph showing all those anomalies Rick, that is truly surprising for what I call a truly high end amplifier. This makes much of what I have seen in class D look better by comparison. Obviously no matter what you choose compromises are part of the package. As my dad used to say, "you pay your money and take your choice" $1500 for the class D vs 10k for the Trinnov makes it pretty easy to choose.
livinon2wheels
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point taken Rick and thanks Buckeye, I suppose there really is no free lunch. If you want more power in the same size case, temperatures will be higher. The question is how high is the temperature inside the devices at the junction at any given case temperature? Thinking in the computer industry, if the cpu gets to 160 C in most computers the fan runs at max and the operating frequency gets throttled back until things cool down. Since amp case sizes are standardized for a given manufacturer, putting a 500 watt amp in the same case a 125 w amp uses will make a huge difference in case temperature I would guess. Buckeye, do you take those kinds of measurements for your amps? I realize heat is relative to the average power the amp is producing at the time of measurement, but is there any measurement standard that exists nowadays? I think back in the 80s they used to test amps at 1/3 power for an hour, which seemed to be reasonable to ensure longevity. Also, is there any possibility of thermal runaway with today's designs?
These amps at full power are about 90% efficient. A bridged 502 feeding 900 watts continuously to a 4-ohm speaker will make about the same heat as a 100-watt incandescent light bulb.
Driving two 4-ohm speakers at full power output will make 450 watts in each channel, so about the heat of two 50-watt incandescent bulbs. So, the same heat production. The output sound will be the same, too, if they are both playing the same input channel.
What makes BTL more powerful is you have two stereo amps for two speakers. But in terms of loudness, it’s only a 3-dB gain.
I ran into this when I was using stacked Advents. I had them paralleled on a 125-watt B&K amp, but those amps didn’t really like impedance that low. So I added a matching amp, and each amp drove two speakers without bridging—like two speakers with a 250-watt amp in terms of loudness. The 502 into two Revel towers nominally has a bit more power (maybe 325) but is probably constrained by the speakers. It’s no louder, but it sounds better in most other ways, particularly as one moves around the room.
Rick “whose speakers probably can’t make 115 dBA SPL with any power input, but the 502 in stereo was enough for the 110dB target” Denney
Driving two 4-ohm speakers at full power output will make 450 watts in each channel, so about the heat of two 50-watt incandescent bulbs. So, the same heat production. The output sound will be the same, too, if they are both playing the same input channel.
What makes BTL more powerful is you have two stereo amps for two speakers. But in terms of loudness, it’s only a 3-dB gain.
I ran into this when I was using stacked Advents. I had them paralleled on a 125-watt B&K amp, but those amps didn’t really like impedance that low. So I added a matching amp, and each amp drove two speakers without bridging—like two speakers with a 250-watt amp in terms of loudness. The 502 into two Revel towers nominally has a bit more power (maybe 325) but is probably constrained by the speakers. It’s no louder, but it sounds better in most other ways, particularly as one moves around the room.
Rick “whose speakers probably can’t make 115 dBA SPL with any power input, but the 502 in stereo was enough for the 110dB target” Denney
Bridging ideally yields twice the voltage swing and thus four times the power or 6 dB gain.
Exactly.
*If the amps are also capable of delivering twice the current.
Thus the word "ideally". This place is pretty pedantic even for me. I was correcting the 3 dB number for an IDEAL amplifier in bridged mode.
cavedriver
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Rick, isn't the Trinnov a Hypex amp? From their product page:
"Like its big brother the Amplitude8, the Amplitude8m is designed to deliver spectacular performance in a luxury home theater but at a fraction of the price. Using the Hypex N-Core Class D output module, each of the eight channels can deliver up to 300 watts RMS at 4Ω."
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