PT-Chris

iTrader: (1)

Now I really did not want to have a pissing match here and would have left alone had it not been for the " everyone wants to be an expert" comment. I did take that personally because never once did I say that I was an expert, or an Electrical engineer. What I was getting at is in my experiences in real life not theoretically speaking, I am yet to see an amplifier put out the rated power at the rated impedance. I dont know what experience you have in the industry and am not trying to knock you in any way, but in my life time I have probably tested over 200 amplifiers that are in the same realm as this one( that realm is the too damn big for street beating so pretty much only to be used for SPL)
Anyone that knows Lauf(Paul) and I know that when we do test things we always try our best to keep the variables as close as possible(ie. voltage etc.) and we also have probably blown up more equipment in the one season that we had the Multi then 50% of this board combined, ( not trying to sound like an *** but we did smoke like 14 woofers in 5 days, if anyone takes offence to that statement I am sorry) not because we dont know what we are doing but because we always push our equipment to the absolute limit so we know how far we can go with it. What I am trying to say is I am not an expert by any means but I think it is fair to say that I can make a statement like I did because of the real world experience I have and not what theory would have us believe. The Ultra class "D" is mostly a statement to make people believe that it is a new technology and I think it is a great idea from an advertising point of view but really has no merrit other then that. If they have really made changes to the class D amplifier topology it really would not be called class D anymore, what they probably have done is to put better grade parts such as fets, ICs, heavier tracers, and have tighter tollerances on these amps then most manufacturers. If that is the case which I believe it is the topology of the amp has not changed but the amplifier will make more power with the better grade parts then if it did not have them, but it is still a standard class D amp design.

Okay as for the 10k RMS with 900 amps and 14.4 volts would mean that this amp would be 77.5% efficent at .45 ohm and that is on a resistive load not a reactive one. In all of the testing that I have done I have never seen an amplifier be almost 80% at any load other then 4 ohm, and in my experiences as the load drops the efficency goes right out the window. I am not saying that it is impossible to maintain high effiency at loads of that nature but is highly improbable.
Here is an example of a manufacturers rating and real life results. We attained these results from a Visonik V4000XD amp two years ago.

resting impedance was 0.75 using a TREO CSX 18 dual 1.5. Once placed in our vehicle there was no rise in resting impedance, and the reactive load is unknown but is irrelavent in this example because the more it rises the more efficent the amp should become. It was the only thing that was connected to our 26 8 volt batts and the resting voltage after sitting for 1 hour was appx.17.6 volts which was taken with a fluke true RMS DMM. we also measured the amount of amps pulled using a Fluke true RMS clamp meter so we know the test was accurate but I cant remember how much current was pulled. We measured the AC output at the amplifier with the Fluke and we found that the amp produced 5292 wrms which was more than the manufacturer rated it for yes but we had load it down to 0.75 to get that power were the rating was 4000wrms at 4 ohm 17.9 volts, do the math on that and if that were true the amp would have to be 90% efficent to make the power they say it does, that is impossible with a standard OE class D board like that amp is. Like I said I am by no means an expert and have never claimed to be one, all I am stating is that the numbers that they claim are not impossible but with the technology we have now in the 12 volt industry which I have been in for almost 10 years now ( since I was 14) I have tested, read about, and grenaded ALOT of amps and I say that the numbers claimed are very IMPROBABLE with todays amplifiers. So once again I have gone on a huge rant like I always do but in this case I feel that it was justified because I needed to prove my point. alos here are the formulas that I used to get the numbers I got above.
The first is done by measuring what the amp is pulling in DC volts and DC amps.
VxA/E=appx. WRMS output
V= voltage
A= amperage drawn
E= efficency
here is the same equation with numbers I found it would take to get 10K RMS using the values that were stated in the above post:
14.4x900/77= 9979.2 WRMS, 900 amps of current draw through 2 awg wire!!!! it must be a 4 inch run to the amp...
I also checked my numbers using the formula to get WRMS from the output numbers of the amp.
P=VxV/I
same equation but with the numbers it would take to make appx. 10K RMS.
9940.5WRMS=141x141/0.5
P= Wattage output
V= AC voltage produced on speaker output
I= resistive load
I chose 0.5 ohm because it was a round number and is very commonly used but is also going to become reactive and rise during testing so the voltage produced will go up when the ipedance starts rising.
I also have a hard time believing that at half ohm this amp will output 141 Volts AC which is enough voltage ( not sure how many amps would be needed) to possibly run the microwave in my kitchen!!!
I am not hating on you or anyone else for that matter I am merely stating my opinion and backing it up with theoretical proof, and we all know theory means nothing in real life 80% of the time.

[ January 30, 2005, 09:39 PM: Message edited by: orion ]

Sassmaster

iTrader: (2)

10,000 RMS is a great numbe for advertising department...

loudsubz

Now I really did not want to have a pissing match here and would have left alone had it not been for the " everyone wants to be an expert" comment. I did take that personally because never once did I say that I was an expert, or an Electrical engineer. What I was getting at is in my experiences in real life not theoretically speaking, I am yet to see an amplifier put out the rated power at the rated impedance. I dont know what experience you have in the industry and am not trying to knock you in any way, but in my life time I have probably tested over 200 amplifiers that are in the same realm as this one( that realm is the too damn big for street beating so pretty much only to be used for SPL)
Anyone that knows Lauf(Paul) and I know that when we do test things we always try our best to keep the variables as close as possible(ie. voltage etc.) and we also have probably blown up more equipment in the one season that we had the Multi then 50% of this board combined, ( not trying to sound like an *** but we did smoke like 14 woofers in 5 days, if anyone takes offence to that statement I am sorry) not because we dont know what we are doing but because we always push our equipment to the absolute limit so we know how far we can go with it. What I am trying to say is I am not an expert by any means but I think it is fair to say that I can make a statement like I did because of the real world experience I have and not what theory would have us believe. The Ultra class "D" is mostly a statement to make people believe that it is a new technology and I think it is a great idea from an advertising point of view but really has no merrit other then that. If they have really made changes to the class D amplifier topology it really would not be called class D anymore, what they probably have done is to put better grade parts such as fets, ICs, heavier tracers, and have tighter tollerances on these amps then most manufacturers. If that is the case which I believe it is the topology of the amp has not changed but the amplifier will make more power with the better grade parts then if it did not have them, but it is still a standard class D amp design.

Okay as for the 10k RMS with 900 amps and 14.4 volts would mean that this amp would be 77.5% efficent at .45 ohm and that is on a resistive load not a reactive one. In all of the testing that I have done I have never seen an amplifier be almost 80% at any load other then 4 ohm, and in my experiences as the load drops the efficency goes right out the window. I am not saying that it is impossible to maintain high effiency at loads of that nature but is highly improbable.
Here is an example of a manufacturers rating and real life results. We attained these results from a Visonik V4000XD amp two years ago.

resting impedance was 0.75 using a TREO CSX 18 dual 1.5. Once placed in our vehicle there was no rise in resting impedance, and the reactive load is unknown but is irrelavent in this example because the more it rises the more efficent the amp should become. It was the only thing that was connected to our 26 8 volt batts and the resting voltage after sitting for 1 hour was appx.17.6 volts which was taken with a fluke true RMS DMM. we also measured the amount of amps pulled using a Fluke true RMS clamp meter so we know the test was accurate but I cant remember how much current was pulled. We measured the AC output at the amplifier with the Fluke and we found that the amp produced 5292 wrms which was more than the manufacturer rated it for yes but we had load it down to 0.75 to get that power were the rating was 4000wrms at 4 ohm 17.9 volts, do the math on that and if that were true the amp would have to be 90% efficent to make the power they say it does, that is impossible with a standard OE class D board like that amp is. Like I said I am by no means an expert and have never claimed to be one, all I am stating is that the numbers that they claim are not impossible but with the technology we have now in the 12 volt industry which I have been in for almost 10 years now ( since I was 14) I have tested, read about, and grenaded ALOT of amps and I say that the numbers claimed are very IMPROBABLE with todays amplifiers. So once again I have gone on a huge rant like I always do but in this case I feel that it was justified because I needed to prove my point. alos here are the formulas that I used to get the numbers I got above.
The first is done by measuring what the amp is pulling in DC volts and DC amps.
VxA/E=appx. WRMS output
V= voltage
A= amperage drawn
E= efficency
here is the same equation with numbers I found it would take to get 10K RMS using the values that were stated in the above post:
14.4x900/77= 9979.2 WRMS, 900 amps of current draw through 2 awg wire!!!! it must be a 4 inch run to the amp...
I also checked my numbers using the formula to get WRMS from the output numbers of the amp.
P=VxV/I
same equation but with the numbers it would take to make appx. 10K RMS.
9940.5WRMS=141x141/0.5
P= Wattage output
V= AC voltage produced on speaker output
I= resistive load
I chose 0.5 ohm because it was a round number and is very commonly used but is also going to become reactive and rise during testing so the voltage produced will go up when the ipedance starts rising.
I also have a hard time believing that at half ohm this amp will output 141 Volts AC which is enough voltage ( not sure how many amps would be needed) to possibly run the microwave in my kitchen!!!
I am not hating on you or anyone else for that matter I am merely stating my opinion and backing it up with theoretical proof, and we all know theory means nothing in real life 80% of the time. </font>[/QUOTE]like you keep saying

"your no expert"

loudtdi

iTrader: (1)

Orion,

I find it hard to believe that you have never tested an amplifier that makes its rated power.

Have you ever tested an amp that has one of those sheets that come with the amp stating how much power the individual amp made when tested after production?

Haunz

iTrader: (3)

I think Id probably agree that 10kw is probably not contiunous RMS... especially with a pair of 2awg power terminals... a pair of 1/0 probably wouldnt even cut it...

But FYI achieving 90% effeciency at full bore isnt a major feat for a good class D design... and BTW effeciency isnt effected by load, only duty cycle...

Anyway, Iam still sure they (hiphonics) probably tested on the verge of both current and voltage clipping for 5ms with 18V input..


I think Id rather own a JBL/Crown beast... [img]graemlins/headbang.gif[/img]

PT-Chris

iTrader: (1)

It is the truth that I have never found an amp that makes rated power at the rated impedance, now the majority of the amps that I have tested are generally used for SPL so the ratings are 2000+ wrms and none have done the power the manufacturer claims at the impedance they claim.
I have not tested an amp that has a birth sheet, as far as I know and there could be lots that do but MTX is the only company that "I" have seen a birth sheet included with amplifiers that are generally used for SPL like the MTX 1501.
I know ARC Audio does include them with there XXK line and the exceed the manufacturer ratings but the ratings supplied by the manufacturer is low right off the bat and who uses a 2150 XXK in SPL..... All I am saying is that I have not nor do I know anyone that has tested an amp that is used in SPL that has made rated power at the voltage and the impedance that the manufacturer has supplied. The efficency dropping with impedance drop is not a fact but just what I have found happens in the testing that I have done and may not always be true. Now if the Hifonics does make 10K RMS how much of that power is usable??? Is it 10K at 10% T.H.D?

Haunz

iTrader: (3)

^ If you look at most power vs THD graphs you will see that THD will generally skyrocket with little gain in power.... so rating at %10 vs 1% means little IMO...

MB

I know of an amp that is rated at 6KW but does 9800+Wrms [img]tongue.gif[/img] There is no way that this amp can do it with only 2 guage inputs ... try 3/0

Prolifik

iTrader: (7)

nice amp

PT-Chris

iTrader: (1)

That is very true no dispute here but..... (c'mon you knew it was coming) 2000 WRMS @ 1% THD is still IMO 2000 WRMS of usable power, where if the same amp is capable of 2500WRMS @ 10% THD really to me you still have 2000WRMS of usable wattage even if it is only being used for 3 seconds there is so much signal that is outside of that AC wave that the output to the woofer would be so clipped that you would be better off using the 2000WRMS with only 1% THD instead. Just my opinion but Haunz is right in what he said I would rather have a little less power but have it cleaner as I believe there would be very little if any gain in SPL.