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here I go..CE 2000 trouble


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#1 Karel

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Posted 24 April 2006 - 09:33 PM

Just a few days ago I was said here, that none of my Crowns never let me down..well..here I go. I noticed last weekend that one sub (JBL Mpro 255S) is not working right. Sound was weak and "weird".I use one CE 2000 bridged for each sub. I just tested both amps the same way at home. Well the one with weird sound did not work at all. There was only not too loud buzz in a speaker. When I turn off and back on the amp, there was sound in the speaker (I used CD for the test) but no matter if the knob on the amp was all the way up, or down-the amp was putting out the same level of power...but very weak sound,distorted. I got the amp a year ago-new. I still have the orig box. Should I send it for repair? Looks like a serious trouble to me unsure.gif . If anybody is familiar with these "symptoms" please let me know. I would appreciate it very much. The number on the label is CE 2000-C409961. What is the best way to get fast service? There was a guy on musiciansfriends.com complaining, that he sent his Crown 3 weeks ago for service and nobody touch that amp yet. I found hard to believe that. Last question for CE 4000 owners. I would have to use now CE 4000 for two pairs of JBL Mpro 225.Speakers rated 500w and 2000W peak. They are 4 ohms. How the amp would "feel" to run 2 of these cabinets on each side parallel? It would be  load 1000W in 2ohms each side for the amp. I really don't want to damage another amp! Thank you for reading this! Karel

#2 Bud Bolf

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Posted 25 April 2006 - 09:14 AM

Hi Karel,
Sorry to hear about the amp.
Are you sure that it is the Amp?
When checking out the Amp did you put the good CE2000 on both speaker cabs and they both worked ok?
I just want to make sure that the Speaker cab does not have a blown speaker.
If both cabs work properly with the good CE2000 but not with the other one then it is probably the Amp.
Also the Inputs to both amps, is it the same as in a Y connection, using the in's and out's that the good CE2000 works with, remove the Amp and use the same in's and out"s with the questionable CE2000 and it is still bad.

Crown does have Authorized Repair facilities around the country, go to the main website and check under Service and Support.
It will still be no charge and under warranty but if there is a place near you that you can actually drop it off and pick it up when they are done, will save you time.

As far as the CE4000, at 2 ohms it puts out 1400 watts, which would be 700 watts per cab.
CE4000 specs here: CE4000 Specs.

Good luck,
    Bud

#3 Karel

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Posted 25 April 2006 - 03:33 PM

QUOTE(Bud Bolf @ Apr 26 2006, 02:14 AM)
Hi Karel,
Sorry to hear about the amp.
Are you sure that it is the Amp?
When checking out the Amp did you put the good CE2000 on both speaker cabs and they both worked ok?
I just want to make sure that the Speaker cab does not have a blown speaker.
If both cabs work properly with the good CE2000 but not with the other one then it is probably the Amp.
Also the Inputs to both amps, is it the same as in a Y connection, using the in's and out's that the good CE2000 works with, remove the Amp and use the same in's and out"s with the questionable CE2000 and it is still bad.

Crown does have Authorized Repair facilities around the country, go to the main website and check under Service and Support.
It will still be no charge and under warranty but if there is a place near you that you can actually drop it off and pick it up when they are done, will save you time.

As far as the CE4000, at 2 ohms it puts out 1400 watts, which would be 700 watts per cab.
CE4000 specs here: CE4000 Specs.

Good luck,
    Bud
View Post

Thanx!!! Yes...I did already everything to make sure, that it is the amp. I will send it for repair. What is interesting...the input signal light is working, there is no fault light on. Everything seems to be fine "optically". I switched the amp to both channel driven as well...same result. I'm happy I have spare amp! Thank you one more time Bud! Karel

#4 Karel

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Posted 25 April 2006 - 05:03 PM

QUOTE(Karel @ Apr 26 2006, 08:33 AM)
QUOTE(Bud Bolf @ Apr 26 2006, 02:14 AM)
Hi Karel,
Sorry to hear about the amp.
Are you sure that it is the Amp?
When checking out the Amp did you put the good CE2000 on both speaker cabs and they both worked ok?
I just want to make sure that the Speaker cab does not have a blown speaker.
If both cabs work properly with the good CE2000 but not with the other one then it is probably the Amp.
Also the Inputs to both amps, is it the same as in a Y connection, using the in's and out's that the good CE2000 works with, remove the Amp and use the same in's and out"s with the questionable CE2000 and it is still bad.

Crown does have Authorized Repair facilities around the country, go to the main website and check under Service and Support.
It will still be no charge and under warranty but if there is a place near you that you can actually drop it off and pick it up when they are done, will save you time.

As far as the CE4000, at 2 ohms it puts out 1400 watts, which would be 700 watts per cab.
CE4000 specs here: CE4000 Specs.

Good luck,
    Bud
View Post

Thanx!!! Yes...I did already everything to make sure, that it is the amp. I will send it for repair. What is interesting...the input signal light is working, there is no fault light on. Everything seems to be fine "optically". I switched the amp to both channel driven as well...same result. I'm happy I have spare amp! Thank you one more time Bud! Karel
View Post

Bud! Thanx again for the advice! I had no clue, that I might get service right here in town!!! I would pack it and send it to the factory..oh well..I just spoke over the phone with a guy who will look at the amp tomorrow-the service is just around the corner!!!! That is great! If I'm lucky enough I will have the amp back on Thursday..so I would not have to change anything for this week gigs(three of them) And looks like its gonna by free service(the amp is one year old).FANTASTIC! Karel

#5 Bud Bolf

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Posted 26 April 2006 - 07:43 PM

Hi Karel,
In checking your Speakers specs and this from JBL,
JBL Power Amp needed

Indicates that to drive these Speakers to Peak levels is not advisable.
When Bridging a CE2000 at 4 ohms that comes to 1950 watts per Cab.
Your JBL Mpro 255S cabs are: 500 watts / 2000 watts Peak.
JBL mentions to drive your speakers at twice the watts rating and not the peak rating.
Double the 500 watts would be 1000 watts, but your double that!

I am wondering if this had anything to do with your Amplifier failure.
You are using a driverack with the JBL 255S tunings correct.

Later,
   Bud

#6 NWCA

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Posted 11 June 2006 - 01:50 AM

As a custom audio designer, i say this.

NEVER... EVER go by the peak power rating of a speaker. ALWAYS by RMS to 40-50% above RMS, anymore and you risk thermal damage to the speakers and in some rare cases short circuit the amplifier from having a crossed circuit after the speaker's VC *voice coil* has blown.

also remember, any and all speaker drivers can blow WAY before they reach RMS aswell when not crossed or highpassed right. all speakers have something that is called Xmax. this is the linear output area that a speaker has to move and recreate sound without any distortion or damage to the VC. going over the Xmax a little is ok, too much can cause a big dent in you'r savings...

my suggestion, find out exactly what the model of JBL drivers those are and gather up the T/S specs on the drivers *woofers*. if you have the time you can download and toy around with WinISD Pro. it's a free program used to model and help design speaker cabenits. you can use it to design the most basic speaker cabenits to some of the more difficult cabenits like fine tuned 4th order bandpasses, 6th order bandpasses and Iso-Barik *Compound* speaker cabenits. this program will show you what the speaker should be capable of with the desired speaker cabenit measures at what ever power and will show you just how much power you should throw at it without going past Xmax.

WinISD Pro is found here - Linear Team

*for some points with the program that are asked frequently at www.speakerplans.com/forums*

All model results are specified under half space readings, meaning, any and all models shown to you is what you should get out of you'r design at 1 meter distance with the speaker cabinet playing outside sitting on the ground without any other walls around it. you can specify what wattage of power to the box you will be throwing and it will give you a full modeled SPL/RTA read out. if you want to have the speaker sitting near a wall during you'r play and want to know what you'r getting out of that *which is known as 4th space*. just add a 12db EQ gain at 60hz with a Q of .25-.5. this models what happens when natural amplification is in effect. for a corner *8th space* add 24db at the same point and Q instead of 12. if in a corner on the floor with a ceiling no higher then 12 foot, add in 32db gain in the same point and Q. this will show you an "about" effect of what happens to bass output when the spacing is changed, generally a massive effect too 25hz-120/150hz.

-hope i've supplied enough help for you, cheers!-
NeverWinter

#7 Lou

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Posted 24 June 2006 - 02:07 PM

First thing in troubleshooting an amp is checking the speaker system. This should be done with a DVM and it should not measure 0.0 ohms.
High power speakers will usually 5.9 ohms or somewhere around there.
If they read really low say 2.9 ohms or so, it probably has some shorted turns in the voice coil. The speaker may or may not sound bad with just just a few turns shorted. But the amp will have to work harder to make the same sound.
This can cause output transistor failure if its cranked up.
So always check the speaker system before connecting an amp.