AVS › AVS Forum › Audio › DIY Speakers and Subs › Measuring Amplifiers
New Posts  All Forums:Forum Nav:

Measuring Amplifiers - Page 23

post #661 of 1913
4/26/08 at 1:33pm
Quote:
Originally Posted by Looneybomber View Post

However, if an amp (like the Dayton that's creating all the fuss) does an excellent job at 32ohms, but wont keep increasing power below 8ohms, will fail to power 4 ohm subs with authority until their resistance values increase to a more friendly level. Those frequencies will then either be played at a reduced output and/or the distortion is going to sore. So maybe, that amp shouldn't be rated to 4ohm, but instead, 6ohms?

An amplifier doesn't have to increase power as impedance drops, it's not a
mandatory requirement to be a good design. All you need to know is what
the lowest load it can drive and still become a stable amplifier. In car audio
there is one brand that has the same power rating [even tested] from
1.5 ohm - 4 ohm, it was designed like this on purpose.

If the Dayton does 500W @ 8 ohm and 4 ohms and is stable, then it is
what it is and you accept it as it's performance envelope. Knowing this
helps your speaker design. If your design assumed 1000w @ 4 ohms, then
the desgn will not perform as predicted.
Reply
Reply

AVS Top Picks

post #662 of 1913
4/26/08 at 2:07pm
Quote:
Originally Posted by thylantyr View Post

It's been discussed. Chuck has his testing goals defined at the beginning
of this thread.

And the specific questions were asked as some subwoofer amplifiers can have some surprises that are un-expected, if not illogical, speaking from experience here.

In fact some such amplifiers have longer time constant limiters that will cut power to about 1/2 after a few seconds. Sometimes it's there to protect components that can't deliver the power continously for whatever reason.

Quote:


Because audio forums are generally not electronics engineering forums,
people tend to speaker 'consumer' so everyone knows what is going on.
I try to use the term 'rms test method' to describe what you said.
Watts RMS is fine too, ie 1000W RMS. Continuous is another animal that has
time as the missing variable in product specs, ie 1000W RMS continuous is
pretty vague. 1000W RMS continous for 1 hour before going thermal is more specific. .. even that has missing variables as what is ambient temperature.

A million ways to test amplifiers.

Point missed. The RMS descriptor after a power value is incorrect and imprecise terminology.

1000W continuous power is a pretty clear definition if the load is also defined.

Of course much of the confusion in the subwoofer amplifier realm is the simple reality that we drive subwoofers/speakers with Voltage, not power.
Reply
Reply
post #663 of 1913
4/26/08 at 2:36pm
Sometimes shorthand communications is easier to understand, this is one of those
rare situation where it works fine and people understand it better.

Saying 1000W RMS is clear. It's assumed the test was an RMS test methodology.

You can say 1000W continuous but it's just as vague.

Nice article here;
http://www.hifi-writer.com/he/misc/rmspower.htm

Who is going to say 1000 long term almost undistorted sine wave average power into a resistive load. ????? nobody is.....

You can take this topic very deep, but the fact remains that people understand the shorthand best because consumers may not be engineers.

Quote:


Of course much of the confusion in the subwoofer amplifier realm is the simple reality that we drive subwoofers/speakers with Voltage, not power.

If all consumers were engineers, then amplifiers might be rated like this.

Hypothetical {simplified}
PLX3402 - 100v rms @ 8 ohms/ch
PLX3402 - 80v rms @ 4 ohm/ch
PLX3402 - 60v rms @ 2 ohm/ch

Of course consumers understand this rating method
Reply
Reply
post #664 of 1913
4/26/08 at 3:09pm
Quote:
Originally Posted by NEO Dan View Post

Alex,
smaller less efficient speakers would need more power to get loud. The next time you are looking at speakers check out the the 2.83v sensitivity. If you had speakers that were 3dB more efficient that would be like having double the amp power.

A pair of 15" 3-way cerwins that I just sold was 102db @ 1w/m

I know you get more from some than others. With that same AVR those CVs would make your ears bleed. The Paradigms are 89 dB iirc. If I can find an efficient speaker that sounds good to me I'll do it, but so far the CVs and all horn types I've heard are just "too something" - too piercing in the case of klipsch, and too damn loud without good definition in the case of the other.

Have you got a good suggestion?
Reply
Reply
post #665 of 1913
4/26/08 at 3:49pm
Quote:


Dayton Test:
In fairness to the other amps tested (all in the same manner) at least they did not fall on their a** at 4 ohm loads this badly and most pro's good to 2 ohm...

Let's face it, if I am a consumer and I need an amp to drive a 4 ohm subwoofer load and I have a choice of products - this $400 Dayton amp barely matches the performance of a $220 O-audio 500W plate amp, and would be a huge disappointment versus a Behringer EP2500. With the Behringer, I can get two channels at 650W (4 ohm) for less than the Dayton.

For $300, I can have the Behringer EP2500 that can compete with a Crown K2at more than double the price - now that's value.

So at the end of the day to me the consumer, what is the better deal?


It depends, I kept the Dayton driving my 2 Q18s (4 Ohms) (eDs LT/1300 driving the other 2 Q18s) instead of my EP2500 driving all 4 because it just works better with my setup.

No noise, auto on/off, RCA connections, Voltage match (no problems with unbalanced to balance) were all huge benefits for me. The other benefits is that it can be a plate amp and some people want subs with an amp right in them then some huge rack mount fan blow pro amp.

I couldnt even tell that there was missing power either, only this test showed me so. I would say I seldom drive my subs hard considering the fact that I can literally shake my house with them using the Dayton amp I would say it covers my needs still. I guess its true that IB arrays really dont need that much power period.

Also remember Dayton has posted and said that their testing methods show better power @ 4 ohms. The way chuck tests may work for some amps and may not work for other amps. Its not an absolute test on how the amp performs in our homes though and that is something we should remember.

Yes, the Dayton amp falls on its butt during Chuck's 4 Ohm test but does that really mean much if other real world tests show that it performs pretty well??
Reply
Reply
post #666 of 1913
4/26/08 at 4:24pm
Quote:
Originally Posted by penngray View Post

Yes, the Dayton amp falls on its butt during Chuck's 4 Ohm test but does that really mean much if other real world tests show that it performs pretty well??

Sure it does - if they are advertising it as comparable to pro-audio equipment and charging a premium for it.
I would question the test if all the other amps perform poorly as well - strange that only the Dayton falls flat on its face at 4 ohm load.
I'm sure the amps that stand up to the more demanding test would perform just as well or better than the Dayton in these other "real world" tests you refer to.

In this case how would you justify it's performance driving a 4 ohm load at $400 compared to a $220 O-audio 500W plate amp with roughly the same features?

I think buyers would be OK if it delivered 850W or better and not feel cheated in paying for a 500W amp.
Reply
Reply
post #667 of 1913
4/26/08 at 4:57pm
Quote:


Sure it does - if they are advertising it as comparable to pro-audio equipment and charging a premium for it.
I would question the test if all the other amps perform poorly as well - strange that only the Dayton falls flat on its face at 4 ohm load.
I'm sure the amps that stand up to the more demanding test would perform just as well or better than the Dayton in these other "real world" tests you refer to.

In this case how would you justify it's performance driving a 4 ohm load at $400 compared to a $220 O-audio 500W plate amp with roughly the same features?

I think buyers would be OK if it delivered 850W or better and not feel cheated in paying for a 500W amp.

You dont know that?? This test is just one type of test, you can not conclude that the Dayton amp only performs as well as the O-audio amp.

You can conlude that under Chuck's testing conditions the O-audio amp is the better amp but its already posted that real world conditions and this testing method dont not match each other. That simply means that the Dayton amp can still beat the O-audio amp in real world conditions.

Im not debating if the o-audio plate amp is good enough Im just saying you can not conclude what you did based just on this ONE testing method. I have not concluding anything yet and that is WHY we emailed Dayton on this. Lets wait and see before you make such conclusions.

Lets see other tests confirm this, In the real world of science never do they simple do one test, then say "YEP, Here are the results". Show me other tests then I will start concluding something.

I have nothing to gain or lose either, I own too many amps to care too I just think something shouldnt be given a bad rap if the testing is really applicable to real world applications.

What if other test show good performance? Then what do you start posting?
Reply
Reply
post #668 of 1913
4/26/08 at 5:00pm
Quote:


strange that only the Dayton falls flat on its face at 4 ohm load.

The EP2500 failed to stay running at 4 ohms bridged so dont get too excited about what this stuff really means!!!
Reply
Reply
post #669 of 1913
4/26/08 at 7:15pm
Quote:


That simply means that the Dayton amp can still beat the O-audio amp in real world conditions.

I fail to see where you can draw such a conclusion...perhaps it MAY beat the O-Audio, but has the O-audio even been tested? Too my knowlege this is the first plate style amp Chuck has tested......I eagerly await more.
Quote:


Also remember Dayton has posted and said that their testing methods show better power @ 4 ohms.

Go figure.....Lets see, they also said it produced 1000 watts at 4 ohms.....they were quick to question the test bed, but have yet to state thier testing methods....or show us said results......How Come? Helloooooooooo Dayton......Where at you now?

Quote:


The way chuck tests may work for some amps and may not work for other amps.

Would be nice to see some tests that show definativly that this method does not in fact correlate to "real world conditions" What would it take, several burst tests?
Quote:


Its not an absolute test on how the amp performs in our homes though and that is something we should remember.

Actually the test is quite absolute, however how we use the amps is the variable. Just what are "real world" conditions anyways?
Reply
Reply
post #670 of 1913
4/26/08 at 7:40pm
Fact of the matter is at 4 ohms this amp faired the worse of all the amps tested so far. Granted the testing method involved maybe brutal and not entirely indicative of how the user would utilize the amp. But, this being said, these other amps that faired much better would also gain an increase from these different test conditions as well. Are we to believe that this simple plate amp in a box is so sophisticated that under different test conditions it would increase at a level of performance higher than the other amps Chuck has tested to date? I guess its possible, but I highly doubt it.
Reply
Reply
post #671 of 1913
4/26/08 at 8:32pm
Chuck's tests are evil. Sourrounded by secrecy...yeah right. Scream wolf because some MONSTAH AMP known for UBBER power failed to meet spec...
Reply
Reply
post #672 of 1913
4/26/08 at 8:50pm
Quote:


Chuck's tests are evil. Sourrounded by secrecy...yeah right. Scream wolf because some MONSTAH AMP known for UBBER power failed to meet spec...

exactly
Reply
Reply
post #673 of 1913
4/26/08 at 11:12pm
I dont discredit the tests and I never said they are EVIL either.

Its a simple fact that ONE test does not create an absolute answer no matter how much you guys want to paint it that way. Im not supporting the amp neither Im just saying one type of testing never sets the measurement for 100% garuntee.

You can make whatever decision you want too since you have competely control over your opinion. Im not just a single blind mouse following a single pied piper
Reply
Reply
post #674 of 1913
4/26/08 at 11:16pm
Quote:


I fail to see where you can draw such a conclusion...perhaps it MAY beat the O-Audio, but has the O-audio even been tested? Too my knowlege this is the first plate style amp Chuck has tested......I eagerly await more.

Geesh, Did I conclude anything? Nope....I just replied to someone that thought comparing the O-audio amp was better...he concluded something. I simply suggested that we really dont know.
Reply
Reply
post #675 of 1913
4/26/08 at 11:16pm
Quote:


these other amps that faired much better would also gain an increase from these different test conditions as well.


LET ME REPEAT THE EP2500 FAILED THE 4 OHMS BRIDGE TEST.....or did I miss something?
Reply
Reply
post #676 of 1913
4/26/08 at 11:21pm
Quote:


Go figure.....Lets see, they also said it produced 1000 watts at 4 ohms.....they were quick to question the test bed, but have yet to state thier testing methods....or show us said results......How Come? Helloooooooooo Dayton......Where at you now?

Ok, You have 60 posts... you state you are clueless...who are you to ask for squat?....get some experience, get some knowledge then post something. Personally I think Dayton owes us nothing...they have their tests and if we dont like it dont buy the amp. They already posted which I think takes some guts so ATLEAST give them time to get something together. Sorry, Im just cranky tonight but you I just dont get your opinion.

What have you done in the audio world to have such a conclusive opinion? You dont see the OP of this thread ARGUING or TRASHING them? HE has class and just posts the results, he doesnt post trashing comments and he lets everyone just decide. I respect that.

Sorry but I dont understand the preceived attack....if its not an attack it just seems like it too me. If they can not produce results then its cool, their amp doesnt make the grade but I will wait for confirmation instead of being someone who takes one thing as gospel.
Reply
Reply
post #677 of 1913
4/27/08 at 5:21am
Quote:
Sorry but I dont understand the preceived attack....if its not an attack it just seems like it too me.

Never intended to attack you personally.....sorry you took it that way. As for who I am......call me Joe Consumer who wants a little truth in advertising. This just smells a little too much like what we used to have in car audio (maybe still do) with claims of output power way above what the unit can actually produce.

Quote:
I think Dayton owes us nothing..they have their tests and if we dont like it dont buy the amp. They already posted which I think takes some guts so ATLEAST give them time to get something together.

This is the part I don't get. If they already have their test, took the time to come here and post and call into question the OP test methods, which is fine, why not clarify and post their test methods.....as you stated they already have their tests. I don't think it took any guts personally.....posting their test methods would have. Look, I highy doubt Dayton makes this amp in house, more likely they just have some third party design it, build it and stamp their name on it.

Quote:
Sorry but I dont understand the preceived attack....

Well let me state I apologize for that perception. First of all I in no way intented to attact you personally. If my words came across that way I do apologize. Unfortunatly in a forum such as this you can't insert a tone of voice, so often times words come off alot more harsh then they were intended to sound. It is however my perception that the OP has been in a bit of an attack, albeit not direct but implied.
With all this banter about how his test methods don't represent real world conditions, despite being wrapped in nice sugar coated posts, and how these amps he tests might actually perform much better under some mystery test in which no one can seem to agree on continue, doesn't it give him less incentive to keep up with this great service he is doing all of us? Now that I feel would be a great shame. I am quite frankly amazed that the OP would spend so much of his time and money on an endeavor such as this. And as for the fact you state his tests are inconclusive, for the time being I would certainly take his independant third party test results over that of some sales PR guy anyday. It's great Dayton came here and posted.... I will give them credit for that, but what did they actually say? And no, I don't think Dayton is the only culprit bye far, But today they have the dubious honor of being the Wesley Snipes of the audio amp world. For the record, it is my opinion that just because everyone else is doing it (embelishing ratings) makes it no more right. Isn't this just basic logic that we instill in our kids? Yet we give manufactorers a pass on the most basic of principles? Color me confused.
Reply
Reply
post #678 of 1913
4/27/08 at 5:40am
Ok, in an attempt to get this thread heading in a more constructive direction, what is it that we expect out of these amps to give it a pass/fail grade? Would something like the ability to output 75% of its rated RMS output continuos and the ability to reach its rated output for a 30-50 ms burst be a fair standard to expect to get a pass rating? I am curious as to what others think in this regards.
Reply
Reply
post #679 of 1913
4/27/08 at 6:15am
Thread Starter 
Quote:
Originally Posted by Mark Seaton View Post

Hey Chuck,

I have used and worked with these and very similar amps. Long term power delivered probably won't meet the spec, but that could even be intentional by way of limiting or other related methods. I'm in not intending to defend the amp, as most amplifiers are rated in rather rosy conditions. The marketeers dis-information puts the honest guys at a gross disadvantage in the general market, and they have to usually find a point of compromise.

Mark:
I agree with you concerning long term power on this amplifier. In this case, I don't believe it is even the marketeers who have done a disservice but the manufacturer and engineering team that have stated the specs on this particular amplifier. Obviously not knowing the internal workings of the company and the processes involved it is all speculation, but, you can read between the lines when you have the 'owners manual' in your hand. It is a single sheet of paper (double sided) and devotes the same amount of space as the ad on the web to specifications.

AS PUBLISHED:
Measured power output: 512 watts RMS into 8 ohms @ 0.09% THD, 1,024 watts RMS into 4 ohms @ 0.15% THD Signal to noise ratio: 98 dB (A-weighted) Parametric EQ: Frequency: 18-80 Hz, Level: -14.5 to +6 dB, Bandwidth: .1-1 Low pass crossover: 30-200 Hz Phase: 0-180°, continuously adjustable Dimensions: 17-1/2" W x 4" H (2RU without feet) x 14" D Power requirements: 110/220 VAC, 60/50 Hz Dimensions (with feet, without rack ears): 17-1/2" W x 3-7/8" H x 14" D Dimensions (without feet, with rack ears): 19" W x 3-1/2" H x 14" D.

These specifications would lead someone to believe that the amplifier is capable of producing 1,024 watts 'continuous' into 4 ohms. The definition of continuous as it applies here may mean 20 ms on and 10 ms off. Not very continuous. But in some eyes, this may be the 'real world' they are looking for. Which brings this whole discussion back to the question:"How do you measure the output of an amplifier meaningfully?". And that is why the FTC is going back to having hearings and try and come up with a consumer protection definition for amplifier ratings that is meaningful in this current technological era.

Quote:
Originally Posted by Mark Seaton View Post

A few quick questions on the Dayton testing as I haven't kept up with the methods and what you are able to test. What sort of duration was the test you ran on the Dayton? Where did you have the input level on the amp? Did you try to further increase the drive signal into 4 Ohms? I'd be curious at what point the amp hits 1% and 10% THD.

Duration: As long as possible. 8 ohms would run just fine at full power for over 15 minutes. At 4 ohms, less than 60 seconds before shutdown.

Input level: I tried it with the amp gain wide open and I tried it with the generator wide open using the amp level control. No difference.

Distortion: The power topped out at what was stated for 8 ohms and would not significantly raise any higher although distortion and severe clipping would rise. At 4 ohms the amp would shut down before ever getting there.


Quote:
Originally Posted by Mark Seaton View Post

Of course all amplifiers design types clip a little differently. It's ironic that we are still looking for the most zeros to the right of the decimal point rather than focusing on audible distortion.

I generally listen to the output with a very high impedance speaker connected to correlate at what point the numbers really become audible.

Finally, I believe it was Bob Lee or someone else I knew in the pro audio community who had on a few occasions made the clarification that most engineers won't use the term "RMS Power." You can measure RMS Voltage, and you can measure RMS Current. The product of the two result in average power. There is no continuous power waveform from which to take the Root Mean Square. If that was measured over a sufficiently long period of time, it make sense to call it continuous average power.

I know it's a bit of a nitpick, but it is also something that should be clarified when anyone starts trying to pin anyone down for specifications. "RMS Power" is a coloquial term that has been largely created by the audio marketing departments where the engineers didn't have the opportunity to catch it.

I agree, but as was stated, '100 watts RMS' says something to the average non technical consumer. There are no RMS watts!

Quote:
Originally Posted by Mark Seaton View Post

Point missed. The RMS descriptor after a power value is incorrect and imprecise terminology.

1000W continuous power is a pretty clear definition if the load is also defined.

Of course much of the confusion in the subwoofer amplifier realm is the simple reality that we drive subwoofers/speakers with Voltage, not power

Actually Mark, you have just fallen prey to the same misleading quotation that the Dayton amplifier did. In todays world with Class D, H, and T type amplifiers '1000W continuous power at 4 ohms' can be meaningless if the continuous is not defined. Is continuous 500 ms or 60 minutes? Is continuous X time on, X time off? When no definition is stated or exists, then you cannot accurately measure the performance of an amplifier using any method.

As an aside, I was talking with the owner of another 'big' audio website and was told that almost all companies will not specify any distortion number when stating the watts for a multichannel amplifier or reciever when all channels are driven simultaneously. It is because the rated watts can only happen for such a short duration that distortion is considered meaningless and therefore not stated.

BTW, according to the current (and very old) FTC amplifer rating method, only 2 channel amplifiers meant for home/consumer use fall under the umbrella of its method. Which means that all the multichannel amplifiers and receivers, professional amplifiers, mono subwoofer amplifiers, and special purpose amplifers are not subject to the FTC rating method.
Reply
Reply
post #680 of 1913
4/27/08 at 6:15am
Dayton said
Quote:
This amp is driven by sophisticated circuitry designed by Bob Carver.

Is that to mean Bob Carver had a hand in designing this amp or that they merely based part of their design off of a Bab Carver patent? If memory serves me correctly weren't the Carver amps a bit controversial in their own respect? I vaguely remember the term sonic holographic. It is the tracking power supply of Carvers that they are refering to correct? I do have a lowly associates degree in EE, but admittably I have forgotten more than I have retained (don't work in the field) I do remember that bad booze wrecks our young guts, but vodka goes well..... after that I get a bit foggy.
Reply
Reply
post #681 of 1913
4/27/08 at 6:44am
Chuck

How might an inductive load other than a resistive load change the results and what might we expect? In your opininion under your test methods, what should we expect to see in regards to measured vs advertised ratings? Did you have a chance to look at the other features of the Dayton amp? And lastly, could this amp produce its rated power in short bursts?
Reply
Reply
post #682 of 1913
4/27/08 at 6:47am
Quote:
Originally Posted by cluelessngr View Post

perhaps it MAY beat the O-Audio, but has the O-audio even been tested? Too my knowlege this is the first plate style amp Chuck has tested......I eagerly await more.

Yes it has been tested. Start at page one. You'll find it. No, seriously.

Quote:
Originally Posted by penngray View Post

Ok, You have 60 posts... you state you are clueless...who are you to ask for squat?....get some experience, get some knowledge then post something.

Post count doesn't matter. For all we know he could have 10,000 posts in another forum. But they could still be 10,000 posts of crap. Which again, just proves post counts don't matter.
*Insert Fight Club picture about post counts here*
Reply
Reply
post #683 of 1913
4/27/08 at 7:53am
Going on and on about one little sub amp that did not deliver in a test is very nauseating.

Chuck's testing is valid and other amps performed ,a few missed and the owners go up in arms.

The man that could provide worthy info is Bob Carver as he designed the amp,not some one with little clue as how this amp works,and exactly why it would "miss" the spec in this test @ 4 Ohms.
Reply
Reply
post #684 of 1913
4/27/08 at 8:29am
Thread Starter 
Quote:
Originally Posted by cluelessngr View Post

Chuck

How might an inductive load other than a resistive load change the results and what might we expect? In your opininion under your test methods, what should we expect to see in regards to measured vs advertised ratings? Did you have a chance to look at the other features of the Dayton amp? And lastly, could this amp produce its rated power in short bursts?

http://sound.westhost.com/patd.htm

See number 2.0 - The Loudspeaker Load

This is a simplifed but very good explanation about some of the factors that go into driving a loudspeaker. They are quite unpredictable unlike driving a motor or contactor in industry.

In regards to measured versus advertised ratings? With this amp there is no mention that it won't do 1,024 watts at 4 ohms at .15% THD. But it doesn't do it into a resistive load with a sine wave for more than 500 ms. Now if they want to say it will do it while I scratch my head and rub my belly, why didn't they specifiy the conditions?

Other features, yes, I observed the action of the crossover in the unit and it is generally good. It worked and was accurate at the frequencies listed on the faceplate. But I did not test it.

Yes, this amp can produce its rated power in short bursts. How short? Only Dayton could tell you because it is not listed in the specs.
Reply
Reply
post #685 of 1913
4/27/08 at 8:32am
Just a bit of a curiousity,

Did Bob Carver design this amp or it is merely a design roughly based off of his patent?

http://patft.uspto.gov/netacgi/nph-P...S=PN/4,484,150

My knowledge of patent law is vague at best but I believe they are generally good for 20years. Again not trying to start a flame war, just curious. I quickly read thru the documentation at PE on the Dayton and find no reference to Bab Carver.
Reply
Reply
post #686 of 1913
4/27/08 at 9:23am
Quote:
Originally Posted by TheEAR View Post

Going on and on about one little sub amp that did not deliver in a test is very nauseating.

Yeah, I mean relax. Its just approx 3dB headroom at the top of the SPL range, and I believe its just 300 over dollars?

There are much more expensive and high-profile amps that did not deliver.
Reply
Reply
post #687 of 1913
4/27/08 at 10:02am
Quote:


They are quite unpredictable unlike driving a motor or contactor in industry.

Great link thank you!

As I understand it inductance and capacitance contribute to the equation to give us a continuously variable Resistance. Yet it is this resistance that ultimately determines the output at any one given time (output being referred to as gain, actually output will depend on whether or not the amp can deliver). So what you have is a load who's resistance in constantly changing. The amount of change and at what frequency will be different between speakers and even the same speaker in different settings/enclosures. So then, how do you measure? It at least on the surface (to Joe Blow consumer) appears that manufacturers rate the amps at a nominal impedance, typically 4 and 8 ohms. So when a rating states 1000 watts @ 4 ohms shouldn't it deliver that under a resistive load? At the very least for a specified duration of time? And if they don't specify the duration shouldn’t the average person assume that it can do it constantly? Or is the more of the case let the buyer beware? One can argue that under "real world conditions" an amp will never be asked to produce a certain frequency continuously, and true as that may be what does that really change when the advertiser claims X amp can do X amount of watts into 4 ohms?

Quote:


In regards to measured versus advertised ratings? With this amp there is no mention that it won't do 1,024 watts at 4 ohms at .15% THD. But it doesn't do it into a resistive load with a sine wave for more than 500 ms. Now if they want to say it will do it while I scratch my head and rub my belly, why didn't they specifiy the conditions?

Exactly, this has been my whole gripe from the get go. Be it Dayton, Behringer, or whoever.

Quote:


Going on and on about one little sub amp that did not deliver in a test is very nauseating.

Agreed, but it’s not just about this amp, however they (Dayton) are just merely serving as example of what appears to be the industry as a whole, some of which are better and some worse, but yet all if not most appear to be guilty. Is it wrong to step back and say "hey this is messed up!"? If left unabated at what point will we see 2000 watt amps that only deliver 100 watts?
Reply
Reply
post #688 of 1913
4/27/08 at 11:26am
Quote:
Originally Posted by penngray View Post

LET ME REPEAT THE EP2500 FAILED THE 4 OHMS BRIDGE TEST.....or did I miss something?



just the boat

It failed?
How? What was the standard it needed to pass?

Everyone else seemed impressed that the EP2500 stood it's ground well. I think you are by yourself if you believe it performed poorly.

...maybe go back and read posts #65 through 70 for what you missed.

Quote from the man himself chasw98 (post #67):
Considering the money to be spent on them, for home use, they are fantastic.

That sums it up pretty much.

As for the Dayton, Nobody is saying that the Dayton is a bad amp - at least not for a 500W amp.
Reply
Reply
post #689 of 1913
4/27/08 at 11:44am
Why all the pitchforks crying foul ? lol

A true story. Some guy in cyber decided to get into the amplifier business
but he's clueless on the technicial side. He introduced a few amplifiers on the market
and grossly underrated the power ratings because he doesn't know what they do.

An amplifier costing $400 was rated for 5 watts x 4.

As you can imagine, a few people took the risk and reported back how great it performed
and people were just confused as hell. This particular brand generated publicity and
flame wars on the forums for about 1 years.

Someone finally took amplifier gut pictures and said the guts appear to have
a similar character of brand 'A' and also brand 'B'.

I took those pictures and spent a week digging deep, just good ole' detective work.
I determined the design was good, and probably found out how designed or if it
wasn't already cloned from one of those other brands.

Last, someone has the amplifier tested and it did well, lets say it's a 500 watt amplifier,
much higher than 20 watts as advertised.

The question is.

1. Is the amplifier junk because at first glance it's a 20 watt amplifier?
nah... It's really a 500 watt amplifier.

2. Is the marketing controversial ? Of course, he grossly underrated the product
and it's hurting his sales. He could have send out the amp for testing and rated it
properly or in the vicinity.

3. If he overrated the amplifier as a 250w x 4 amplifier [1000w] , later tested
at 500w, does that make the amplfier junk?
nah... It's really a 500 watt amplifier.
Reply
Reply
post #690 of 1913
4/27/08 at 12:05pm
Quote:
Originally Posted by cluelessngr View Post

Just a bit of a curiousity,

Did Bob Carver design this amp or it is merely a design roughly based off of his patent?

http://patft.uspto.gov/netacgi/nph-P...S=PN/4,484,150

My knowledge of patent law is vague at best but I believe they are generally good for 20years. Again not trying to start a flame war, just curious. I quickly read thru the documentation at PE on the Dayton and find no reference to Bab Carver.


Random thoughts.

1. There are tons of amplifier and power supply patents. The patent office
seems to grant patents for the same patent with just a twist of the theme.

2. Someone clever in audio told me the tracking powersupply idea existed,
then Carver took the concept, did a twist, and got his own patent, I think
in the late 90's. This methodology is what Sunfire is all about.

3. Lab Gruppen also uses that idea that they call class TD. It could be
their own twist on the idea, maybe they pay royalties, who knows, who cares.

4. The idea is great, execution may be poor, even that pro audio company
who can do no wrong in the public eye, failed pretty badly as the design
was analyzed. Since then, they introduced FP+ series, perhaps improved,
but no verified yet.

5. Because it says it has a tracking power supply I wouldn't assume Carver
had his hand in the design. If it says tracking downconverter, that seems
to be a term *maybe* coined by Carver, but I don't know if he owns rights
to it. He uses that word in his Sunfire amplifier white paper.

6. Dayton amplifier says 'Made in China'. In the car audio world, there is
tons of amplifiers either designed and/or cloned offshore, not to mention
there is proamps and home amps. The offshore amplifier is like a weed,
grows everywhere uncontrolled. Doesn't surprise me if the Dayton amp
is just an 'off the shelf' design from offshore and rebadged. Doesn't matter
as long as you know what it really does.

7. Dayton said they will do their own tests. Don't you find this amusing?
If you were sourcing product from offshore, logic says to evaluate the product before you rebadge.
But this takes time and money and most of the
time people probably take their word for it, later they are surprised it didn't
do well because they assumed. Look at the eD LT/1300 amp. 1300w claimed,
but no distortion reference. eD has a history of rebaging and they don't have
in house skill to design electronics .. It's easy for them to get Keiga to
offer them their 1kw amp and rebadge it. Done. Keiga rates their amp at
1kw @ low distortion, 1.2kw @ 10%. If eD says 1300w, are they lying? nope.
People just haven't raised the question on the distortion figure and how the
amplifier gets it's 1300w rating? burst? continuous? etc.

8. There is audio comedy everywhere when you dig deep
Reply
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: DIY Speakers and Subs

AVS Top Picks

AVS › AVS Forum › Audio › DIY Speakers and Subs › Measuring Amplifiers