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Crest CC4000 or CC5500 - Page 3

post #61 of 96
I finally used the block function. I don't have to ignore this thread anymore, woo!
post #62 of 96
@lukeamdman

doesn't he have a point with respect to transformer weight for this class/type of amp though?

maybe crest determined that a smaller transformer was just as good because the system is limited by other dimensions and/or most folks don't want to be moving around 83 pound amps?



if the smaller coil performs just as good as the larger one, why use a larger one? a 2500 va toroidal coil is several hundred dollars, so I suspect that he is right about it being a primary cost contributor.
post #63 of 96
Quote:
Originally Posted by LTD02 View Post

@lukeamdman

doesn't he have a point with respect to transformer weight for this class/type of amp though?

maybe crest determined that a smaller transformer was just as good because the system is limited by other dimensions and/or most folks don't want to be moving around 83 pound amps?



if the smaller coil performs just as good as the larger one, why use a larger one? a 2500 va toroidal coil is several hundred dollars, so I suspect that he is right about it being a primary cost contributor.

The test linked in this thread showing the cc4000 exceeding 3kw in a 4ohm bridge lines up with Crest's specs, so it's obvious to me that the transformer size isn't a limiting factor since the amp tested to specs!

To say that an Emotiva amp, in which the most powerful they have is less than 2kw, is going to outperform the 5500 is ridiculous.

To also say that anything over 1kw isn't important/needed/makes a difference is also insane.
post #64 of 96
Quote:
Originally Posted by lukeamdman View Post

I finally used the block function. I don't have to ignore this thread anymore, woo!

LOL....to funny. Old school amp theory if fine but not useful in a different class amplifier. Maybe if we tested all amps with a max burst at 5 full secs and then see what it can sustain indefinitely then maybe we can talk about PS's. BUT for the most of us needing LARGE amounts of power in a cost effective design (budget concerns) and only needing short bursts of power I don't think anything is going to beat a used CC5500 or new IPR27500.(OEM not a clone)

Peavey/Crest OEM or Clone for those that dont mind a risk. Did anyone ever pop the top/bottom to have a look at the design?

I was still hoping to get a picture of the board and design.
post #65 of 96
http://www.ebay.com/itm/Crown-XLI3500-Stereo-2-Channel-2700-Watt-Power-Amplifier-/370828243033?pt=US_Pro_Audio_Amplifiers&hash=item565715f059

Need I say more. The Crown XLI 3500 over 1000 watts into 8 ohms with hybrid power supply amplification. Now only 649.00 for over 1000 watts into 8 ohms.
post #66 of 96
Quote:
Originally Posted by johnplayerson View Post

http://www.ebay.com/itm/Crown-XLI3500-Stereo-2-Channel-2700-Watt-Power-Amplifier-/370828243033?pt=US_Pro_Audio_Amplifiers&hash=item565715f059

Need I say more. The Crown XLI 3500 over 1000 watts into 8 ohms with hybrid power supply amplification. Now only 649.00 for over 1000 watts into 8 ohms.

Fail.

1kw per channel at 1khz at .5% distortion is a far cry from 1kw per channel from 20hz-20khz at .05% distortion.

It's also not 2ohm stable, and only weighs 4lb's less than the 5500.

For $150 more I'll take more power, less distortion, and a 2ohm stable amp.
post #67 of 96
I thought you had the ignore button selected? biggrin.gif I wasn't going to bother commenting. We all know there are plenty of amps that perform better for budget. BUT some have VERY limited views.
post #68 of 96
Quote:
Originally Posted by chrapladm View Post

I thought you had the ignore button selected? biggrin.gif I wasn't going to bother commenting. We all know there are plenty of amps that perform better for budget. BUT some have VERY limited views.

His dang posts still show on my phone...grrr
post #69 of 96
It should be noted that tests done on the cc 4000 in this case were done in Italy where the line voltage is 220 volt vs american / canadian 110 voltage. As there is twice the voltage at the wall outlet you only need half the current to get the same results vs America / Canada. Where amplifiers are concerned this is definitely one advantage of 220 volt service vs the West. You get twice as much out of the tested 10 amp circuit than you do a 20 amp circuit here which would not be enough here in the west. Still found to be lacking at twice the voltage to the power supply IMO.

Some Audiophiles will actually install 220 volt breakers and run lines to their power amps as the results are much better with twice the voltage! Many car audio nuts would love to double their 12 volt voltage as low voltage is the main struggle with high end car audio, with low ohm loading being the main solution, combined with extra batteries for power supply augmentation. If your power supply is multi voltage you can run a 220 volt line to it on your 110 amp service panel.

I took the time to take a picture of my cerwin vega cv 2800 (Samson SX 3200, HPA A 3200, B52 US 4000 American Audio V 4000) with a measuring tape to show the huge size vs higher name brands of the toroidal transformer you get., and a picture of the CC 4000 for comparison. Both the 2800 and 3200 versions of these amps have the same toroidal. Almost 7 inches in diameter. With a toroid this size on a 2800 and 3200, I would like to see what would be used on a CV 4000 if they made one. Chances are they keep using the same one and just further underrate the toroid. As long as it will register for a few milliseconds these days it seems to be a quantifiable rating for manufacturers these days. It does not seem to matter that eventually your power amp will break down.

You can buy two of these amps and run them in bridge mode for the same price as the crest CC 5500 on mega sale!.




Edited by johnplayerson - 12/8/13 at 12:09pm
post #70 of 96


This CREST CA 9 and a lot of amps are supposedly two ohm stable. The only people that need two ohm stability are those that think they need 2 ohm drivers. All amplifiers are rated
into 8 ohms and all specifications fall soon as you half the load impedance , and fall further soon as you half the load impedance again. You can find broken down crest ca 9 and ca 12 all over the net because they were over driven for too long at a two ohm load. There is no such thing as two ohm stability. All the extra stress will eventually break down your amp,

Output transistors further deteriorate taking all the extra heat, and eventually take less and less power at a faster and faster rate till breakdown. Output transformer protection circuitry will blow and have to be repaired, or if you have none the transformer will melt down. All that metal cannot work without its protective outer layer.

All this low ohm loading causes higher distortion in subwoofers not less, with less subwoofer cone motion control, So you are better off wiriing your LMS 5400 up to higher ohm and giving them a nice 8 ohm resistance, then bridge an amplifier to them so you get lots of extra capacitance.

There is very little benefit to low ohm loading as the diminishing marginal returns after 1000 watts rms are staggering. You need 10000 watts to double the output level of 1000 watts. So if you go into two ohms to get 2000 watts instead of 1000 watts you will get little result, for triple the stress on your amplifier. If i was to use a crown xli 3500 i would use it bridged to one subwoofer at 8 ohms. or power two subs at 4 ohms. Part of the reason i have not tried the Lms 5400 is because of the two ohm coil. I would not run into two ohm even if i could. It makes for great marketing for QSC and CREST, but little benefit to your ear! If you got 4 lms 5400 like you say, I see no reason why wiring each left and right pair in series to 8 ohms and driving each pair with an xli 3500, for only 649.00 each or less, would be a big problem, The 8 ohm scenerio is much better than having 2 ohm load per side, regardless of what amplifier is used.

OBVIOUSLY ONE LINER LAMERS ARE YOUR ONLY SPECIALTY AND YOUR MIND IS NARROW LIKE YOU SAY LUKE SKYWALKER. I suggest you go visit a site like lenard audio to gain some knowledge, that way you will have something constructive to say rather than one liner lamer attack comments. Rockford T2 at 8 ohms each. Two Cerwin Stroker at 8 ohms each Two marathon ma 5050 amplifier paper weights no longer used. 4 alpine swr 10d4 wired to 8 ohm load.
Edited by johnplayerson - 12/8/13 at 4:15pm
post #71 of 96
Another great benefit of low ohm loading is the greater chance of blown speaker due to less restraint on the peaks. These lms 5400 were blown by other stupidity but the same could well happen with an amp wired to low ohm load.

Audio has always been quite simple, but marketers like to invent stuff to make us buy their product over others, and this is where most of the 2 ohm loading comes in. Audio is always better with healthy resistance, your always better off with higher ohm 8 ohm loading than lower. All my amps are two ohm stable but they are never going to see a two ohm load.

Anyway here is some fried lunch, a 2000.00 dollar mistake much like my marathon ma 5050 amps were.

http://www.avforums.com/threads/dual-lms-ultra-5400-sealed-blew-up-melted-coil.1779172/
post #72 of 96
http://qsc.com/products/Power_Amplifiers/Rmxa_Series/RMX_2450a/

Here are the specifications for a qsc rmx 2450a old school amplifier. As you can see they give the 2 ohm specification at 1 percent thd. Yes not .1 or .01 a whole 1 percent THD. 4 ohm bridge mode driving is equal to two channel two ohm driving. So this is what you get when you have a brain fart and want to bridge into a 4 ohm load. Quite the same situation on all amplifiers. Yet we still get self professed audiophiles wanting to bridge into a 4 ohm load for home audio subwoofer duty. Obviously this is idiotic thing to do , especially coming from someone who supposedly has brain farts about distortion.
post #73 of 96
LTD , you are correct in that the OEM toroid is a limiting factor. It is basic math, and the under rating happens worldwide. Very few give a fully rated power supply. Even today with the much lower cost of making toroids, the cost is still the most expensive part they have to deal with. If you go to digikey, you will find thier 1200 watt toroid, is about the same size as the toroid in the CV 2800 , CV 3200. I have never seen them get any bigger, in a two rack space unit., even for the peavey cs 4080Z which is suppose to be 1200 rms. The new millisecond burst maybe is all you will get.

It is quite simple that any two rack space unit, cannot fit a fully rated toroid after around 600 watts RMS. This is where a few of the better manufacturers go to three space units, providing more adequate transformer and capacitance.

My opinion they should just make them all fully rated supplies, and let those who can afford them buy them, rather than rip off the public with strategic reasoning. Lots of Switch mode units around for those concerned about weight.
Edited by johnplayerson - 12/10/13 at 9:19pm
post #74 of 96
Quote:
Originally Posted by johnplayerson View Post

http://qsc.com/products/Power_Amplifiers/Rmxa_Series/RMX_2450a/

Here are the specifications for a qsc rmx 2450a old school amplifier. As you can see they give the 2 ohm specification at 1 percent thd. Yes not .1 or .01 a whole 1 percent THD. 4 ohm bridge mode driving is equal to two channel two ohm driving. So this is what you get when you have a brain fart and want to bridge into a 4 ohm load. Quite the same situation on all amplifiers. Yet we still get self professed audiophiles wanting to bridge into a 4 ohm load for home audio subwoofer duty. Obviously this is idiotic thing to do , especially coming from someone who supposedly has brain farts about distortion.

Considering that you'll never hear 1%, or even more, distortion from the amp in a subwoofer application, it's hardly a big a deal as you insinuate.
post #75 of 96
Both the wear and tear as well as poorer woofer control combined with higher distortion is actually quite a big deal, but if you want to live with it go ahead. You should also note that luke skywalker posts and complains about the .5 percent 1KZ rate of the crown amplifier. For whatever reason I do not see the 20 to 20000 khz rate for the crown listed, which would be much lower. Guess crown wants us to contact them for it, but looking at the Yamaha P7000 , its 1kz rate is a full 1 percent, but falls to .1 20 to 20000 kz, at 4 ohms. so I imagine the crown rate is probably better, given the 1kz rate is better.

Yes not a big deal for people who want to live with unstable low impedance loads which mean zero damping factor, less woofer control and much higher distortion and back emf. Where low impedience is concerned, all rates are lower at lower frequencies and higher at higher frequencies because of the natural slew rate of all amplifiers. However WHOAREU , if you like listening to that kind of crap go ahead, your not the only one that seems to be fooled by the extreme lack of benefit of a low impedance load. According to you, as long as we are pushing subwoofers, it does not matter what the distortion rate is, this is quite foolish, especially seeing as the 4 ohms bridged rate is 20 times over the regular acceptable rate of .02 thd, for audiophiles and that would not even be at full power for most amps. As I have explained its not just distortion that is the issue, back emf combined with erratic woofer control, as well as unwarranted amplifier wear come into play as well.

Looks like you too, got a whole line of valuable information posted there, but it is ok, as it is hardly a big deal, as you insinuate.
Edited by johnplayerson - 12/14/13 at 9:29pm
post #76 of 96
what you say makes sense with respect to increasing the life of the components. what I'm not clear on is what you mean when you say "...poorer woofer control..."

which specs would this show up in?

if a dual 4 driver was wired for 8 ohms and for 2 ohms the damping factor would be different by a factor of four. so if these two combinations (same driver, same amp) were then tested under equal power loads, would 'poorer woofer control' result in more distortion? linear distortion, harmonic, other? would a multiple signal tone that pushes the driver pretty hard reveal significant differences, e.g. the spectral contamination test?

what do you think and/or have you ever measured or seen measured the difference that you are talking about, or can you hear it subjectively?
post #77 of 96
That would be additional distortions in the music that are not included in the THD ratios, as I understand it additional back emf etc(Back emf is generated in the subwoofer via the electrical voltage travelling threw the coil along with magnetic reaction, and travels back up the speaker wire to the amplifier, disturbing the electrical flow. this is greater the lower the load impedance). will result in the woofer moving in opposite directions to the music at times, which means inaccurate reproduction rather than distortion. You should get better bass and better woofer control and better distortion numbers at an 8 ohm load, vs 4 ohm and 2 ohm. Also as stated before there is such a huge drop in gain after achieving 1000 watts, that low ohm loading offers zero benefits vs the cost on the amplifier itself, and only offers further distortions do to low resistance. Resistance is always good not bad. This is why i purchased dual 4 ohm subwoofers as I want the full benefits of a normal resistive 8 ohm load.

Low ohm loading has always been a shortcut to getting more power at a huge cost. It is used a lot in car audio as you are restricted to low voltage so there is a purpose here, as you can not achieve big power without it. Car audio also requires class d, as you cant fit anything else. In home audio you do not need to take this shortcut. Best to bridge an amplifier at 8 ohms on each sub to get high capacitance, and twice the power at half the voltage at 8 ohms than go to low ohm loading. As per the lenard quote below this is the proper way to get more power rather than low impedance load, while lowering distortion, increasing headroom, and therefore dynamic range, for nice deep unrestrained bass.

The main issue is Zero gain for nothing but higher distortions, and amplifier wear. The only reason one would want to bridge into a 4 ohm load or run stereo two ohm load would be the same as the reason for car audio. to get more power out of a small amplifier. Ie, Get 600 watts out of a 200 watt rms amp at 8 ohms to power a 4 ohm 600 watt subwoofer. Not much reason to do this unless you work at Mcdonalds and its the only way to blast your face off. I Always over power and bridge for better results. Not for mains just for subwoofers.

Quote lenard audio

The advantage of bridge is that it delivers the same power as a single ended amplifier with only half the rail Voltage. (40V RMS into 8R = 200 Watt) 40V RMS from a single ended amplifier requires + – 60V rails, whereas 40V RMS from bridged amps only requires + – 30V rails. With bridged amps the speaker is powered from both + – V rail supplies at the same time, instead of alternate between supply rails as with a single ended amp. Therefore Bridge amps make more efficient use of the rail supplies. Also the maximum Voltage across the transistors is half by comparison to single ended amp. Bridge is the most effective method to drive a speaker. The only disadvantage is higher cost.

http://lenardaudio.com/education/12_amps_5.html

See Also Lenard Audio Speaker impedance Z

With a speaker load of 8Ω this amplifier will only be capable of 50 Watt. With a speaker load of 16Ω this amplifier will only be capable of 25 Watt and so on. The higher the load impedance, the cooler and more reliable the amplifier will be, and the lower the internal distortion but less power.

http://lenardaudio.com/education/05_speakers_3.html

As can also be seen the advantage of bridging is actually lost when dealing with 4 ohm loads. See the same first link for more info.

Quote Lenard audio...

By paying close attention we can see that 4 times the power is achieved from bridging 2 amplifiers delivering 40V RMS into a 8Ω speaker (200 Watt) if we are comparing it to a single ended amplifier delivering 20V RMS into the same 8Ω speaker (50 Watts). However when comparing a bridge amplifier delivering 40V RMS into a 8Ω speaker (200 Watt) to a single ended amplifier delivering 20V RMS into a 4Ω speaker (100 Watt) then bridge only appears twice as powerful.
Edited by johnplayerson - 12/15/13 at 12:11am
post #78 of 96
well, perhaps somebody reading is set up to perform this test and could give it a quick go. the question is what to measure to best capture the difference in control, if there is a difference.
post #79 of 96
I am sure many have stopped looking at this thread unfortunately. I am sure things can be tested but having one opinion and clearly ignoring all the other facts about new technology doesn't help.
post #80 of 96
one thing that I'm seeing is reference to higher distortion levels at lower impedances.

i suspect that a large part of that is simply because the lower impedance is producing more power. more power would seem to create more distortion regardless of which impedance is used.
post #81 of 96
Distortion ratings can be as simple as what point you pick on the power curve.

Want to show less distortion? List your power from a slightly lower point on the curve. Want to show more power? Pick a number at a slightly higher point on the curve, albeit at higher distortion.

I like to use the information for my Yamaha M-80 amps to make this point since it gives ratings by a few different methods.

20Hz to 20kHz, 330wpc @ 4 ohms @ 0.02% THD

1kHz, 450wpc @ 4 ohms @ 1% THD

Exact same amp, just how you look at it.
post #82 of 96
Quote:
Originally Posted by johnplayerson View Post

According to you, as long as we are pushing subwoofers, it does not matter what the distortion rate is, this is quite foolish, especially seeing as the 4 ohms bridged rate is 20 times over the regular acceptable rate of .02 thd, for audiophiles and that would not even be at full power for most amps. As I have explained its not just distortion that is the issue, back emf combined with erratic woofer control, as well as unwarranted amplifier wear come into play as well.

Looks like you too, got a whole line of valuable information posted there, but it is ok, as it is hardly a big deal, as you insinuate.

Actually, that's not what I said but, regardless, I suggest you check into the audibility of distortion vs. frequency.

Here's a little tickler for you...
Quote:
Conclusion

Axiom's tests of a wide range of male and female listeners of various ages with normal hearing showed that low-frequency distortion from a subwoofer or wide-range speaker with music signals is undetectable until it reaches gross levels approaching or exceeding the music playback levels. Only in the midrange does our hearing threshold for distortion detection become more acute. For detecting distortion at levels of less than 10%, the test frequencies had to be greater than 500 Hz. At 40 Hz, listeners accepted 100% distortion before they complained. The noise test tones had to reach 8,000 Hz and above before 1% distortion became audible, such is the masking effect of music. Anecdotal reports of listeners' ability to hear low frequency distortion with music programming are unsupported by the Axiom tests, at least until the distortion meets or exceeds the actual music playback level. These results indicate that the “where” of distortion—at what frequency it occurs—is at least as important as the “how much” or overall level of distortion. For the designer, this presents an interesting paradox to beware of: Audible distortion may increase if distortion is lowered at the price of raising its occurrence frequency.
post #83 of 96
LIke is, and should be well known, may as well throw out the manaufacturers specs when you go to low impedance load. Learn something and accept what is naturally better.

Quote from SEK, diyaudio.

It seems that pro amplifiers are much better at playing low impedances
That's not true in general. But in particular there are more amps that are designed (and testet) to be used with lower load impedances. I assume we are speaking of class AB amplifiers here.

The problem is this: the power that an amplifier has to deliver is determined by the (complex) load impedance of the speaker and the output voltage of the amp only.

If the amp can deliver enough current into a connected load at it's nominal output voltage in order not to violate Ohm's law I=U/R and thus P=U*U*I, it is capable of powering a speaker with this impedance. And if it's not capable of delivering enough current, well, then it's just not. Actually it all depends on the power supply and the current capability of the used output transistors.

There are two well known "cheats" in (so called) professional amplifiers:

1. Exaggerating the output stage for much more current than is needed under normal load conditions (so that temperature rises not too much under heavy overcurrent).

2. Compensating the amplifier for high frequency stability in case the damping factor gets too low (e.g. so that the amp does not start to oscillate even when negative feedback is greatly reduced).

Both these steps will leave the whole issue to the power supply. As standard BJT or MOSFET transistors are relatively cheap, it's not very difficult to build many of them into the amp (e.g. twice as much as needed for just a couple of bucks).

The "cheat" is in the fact that a power supply will drop it's voltage under load. Just calculate for yourself: A significant drop of the maximum output voltage under heavy load will lead to an inherent reduction of the maximum output power.

This phenomenon is marketed by many (so called) pro manufacturers under the term "2 Ohm Stability" and does only mean that the amplifier won't break under a 2Ohm load. But it does not mean that the amp is usable with a 2Ohm load, as this power compression does sound absolutely awful and is what lets you recognise an amp as "overdriven" or "underpowered"...

End quote.

You can usually see the result of low impedance load in Car audio utube videos, where half the cone comes out first followed by the other half, (uneven cone excursion). Like i said , you want to listen the that kind of crap go ahead, Some like SPL over SQ. why I will never really understand,
Edited by johnplayerson - 12/15/13 at 11:08pm
post #84 of 96
The emotiva xpr 2. Now if they would only make that transformer 1/3rd the size, and give it at least 12 less capacitors, then we would have a two ohm stable amplifier.


LOL. Got to love sarcasm yes!. I just put a quote form in for two, boy am I going to be sorry.
post #85 of 96
Buy the way WHOARU, I recently noticed your a big QSC PLX lightweight switchmode power supply user, so obviously you are on the far side of the fence from me, to begin with. as I will not be adding to the landfills like most will down the road.

Quote lenard audio


However switch mode power supplies are extremely complex. The high switching frequency technology is in the Rf radio frequency band. This causes major headaches to technically manage containing Rf radiation from the printed circuit tracks and connecting wires within the circuit getting to the outside world and causing Rf noise contamination in radio and TV. Also the circuit operation is extremely fragile, and if any fault occurs (no matter how small) it contaminates almost every sector of the circuit.

Switch mode power supplies are non user serviceable, failures are simply dealt with by trashing the power supply and purchasing a new one. Attempting to service a switch mode power supply is virtually out of the question, except for fanatics who have infinite time. The technology is so complex and fragile that reliable operation after 7 years is not always expected but considered a blessing. As the world converts to using switch mode power supplies and PWM Class D audio amplifiers, they will eventually end up as the dominant mass of rubbish land fills

Fairly standard specifications. I iike the 8 ohm specs, but don't care for Switch mode power supply units.

• Exclusive PowerWave power supply for superior bass and
lighter weight
• Ultra-low distortion (0.03% THD at 8 ohms) and studio-quality
noise floor (-107 dB)
• LED indicators include bridge mono and parallel input modes
• Compact 2 RU, 21 lbs. and 13" deep chassis fits into any rack
• Class H output reduces AC power draw and heat by 40%
(2402, 3002, and 3402)
• Selectable clip limiters and subsonic filters reduce distortion
and protect speakers
• Variable-speed fan for low noise and solid 2 ohm performance
• Both 1/4" TRS and XLR inputs, Speakon™ and shock-proof
binding post outputs
• 3-year warranty plus optional 3-year extension available

Same with these, very little benefit vs the cost going below 8 ohms bridged or into a two ohm load scene.
Edited by johnplayerson - 12/16/13 at 2:57am
post #86 of 96
I'm glad you like the PLX amps. They're great, have performed flawlessly for many years now and I expect them to for a long time yet to come. QSC has been doing it for a long time now, as are most amps from the midline levels and.up. Other then consumer audio, for the most part, only entry level pro audio amps are still "big iron" although even that's starting to change too.
post #87 of 96
Quote:
Originally Posted by johnplayerson View Post

Buy the way WHOARU, I recently noticed your a big QSC PLX lightweight switchmode power supply user

Yes I am. They're great amps.

By the way, I noticed you (I'm sure inadvertently) left out points from Lenard Audio that don't necessary support your agenda, such as this one -
Quote:
Quote from Lenard Audio -

The high switching frequency gives the switch mode power supply a unique advantage of providing a near perfect ripple free smooth and regulated DC supply Voltage that does not decrease in Voltage as extra current is required.

Also what are your comments on that info posted regarding distortion audibility? Pretty interesting, wouldn't you say?
Edited by whoaru99 - 12/16/13 at 5:09am
post #88 of 96
I dont have a problem with the performance of the QSC plx amplifiers. I am just not a fan of them for value. based on the fact they produce the switch mode power supply for pennies on the dollar vs the cost of an Oem toroid, and they keep most of the gain as profit, this combined with the fact they are not likely to last as long as the conventional supply.

Some people will go overboard defending stuff, like the completely garbage marathon ma 5050 amps. These pieces of crap are designed poorly and do not reproduce low end properly, yet when i try to save some people grief, a few owners want to defend their amp. Im sure your QSC PLX will beat the marathon no problem, Its not even an amplifier it really is crap for subwoofers. If people want to argue the marathon ma 5050 is good then they should go buy one. Lucky if they sold 2 of them in the past two years on ebay, but the cerwin amps are selling like hotcakes, no thanks to the people at speakerplansforum who were misrepresenting the amplifier and trashing it with BS reasoning, before I gave them not only an updated picture of the internals,but my take on the amplifier. Someone else is then embarrassed at being corrected and must harrass me lol. Anyway i could easily see the sales were way up after i posted the internals picture.

Again i get a lot of resistance from people that like to low ohm load, I say go ahead if you like it so much, all im saying is benefit is mute vs the amplifier wear and increased
distortion. I got 4 alpine swr 10d4 hooked up to an 8 ohm bridged load which equates to 3600 watts for the 4 1000 watt nominal 3000 peak subs. Now I could have bought 4 dual two ohm of the exact same sub, and wire them to 4 ohm total load. I would then be in a 5000 watt into 4 ohm load situation. The law of diminishing returns here says that extra 1400 watts is very unlikely to make any difference at all over the 3600 i would have had going the other way. All I would be doing is making the job 4 times as hard or more for Zero gain. One of many reasons i say stay away from 4 ohm bridged or 2 ohm load as it is just ridiculous to use it, especially when you do not need it these days. You can buy the subwoofer in almost any impedance, to make things easy.

I was curious to try the lms 5400 at one point but steered away due to the dual 2 ohm coil only available. if I am to bridge I would have to buy 4 and series wire each pair for my liking and this was out of the question to give them a try. Another best way to increase output is just to use more drivers for more displacement and obviously i do this.

People want to talk amplifiers , hey im all game but if you have to go around using poor language and demeanor expect to get the same in return. If everyone waited for a test report these days, before buying an amplifier, very few would have one. Most of the tests these days are done by back yard electricians.

I initially had the yamaha m80 also. I loved the zero distortion rule marketing lol. Darn good amp and it got stolen and replaced by the new yamaha mx 1000u which is actually a nice improvement over the m80 if you accept its quasi class a circuitry vs the m80 30 watts class A vs switching to Ab. I really love yamaha, but i know i got to replace these amps eventually. I bought my first one at 18 yrs old. I made 4 dollars an hour at a gas station and saved up $1100 to buy the M80

On the bad news side so far emotiva says they will not ship me the XPR 2s. They said they are not shipping those international at this time. I did tell them im only 150 miles from Grand forks north dakota, and asked if they could solve for this huge logistics problem lol.
Edited by johnplayerson - 12/16/13 at 3:10pm
post #89 of 96
FWIW, I use Crown CE4000s for my subs. I run them bridged into 4 ohm cabinets.

I get a kick out of this statement from the CE4000 specs sheet...
Quote:
The CE4000 not only handles but excels at 2-ohm loads. In repeated stress tests, the CE4000 continued to perform at levels 12 dB into clip, long after the competition had shut down.

They are SMPS with PFC and in this case the output stages are switching as well. These will maintain full rated output down to roughly 95V on the AC mains.

I've seen some rumors these were the basis for the Crown I-Tech amps.
post #90 of 96
Quote:
Originally Posted by whoaru99 View Post

FWIW, I use Crown CE4000s for my subs. I run them bridged into 4 ohm cabinets.

I get a kick out of this statement from the CE4000 specs sheet...
They are SMPS with PFC and in this case the output stages are switching as well. These will maintain full rated output down to roughly 95V on the AC mains.

I've seen some rumors these were the basis for the Crown I-Tech amps.

I'm telling you man, click that magic button like i did and this thread looks a lot better!
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