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CREST Pro 9001 - 4 ohm performance

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Category: General
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=97822
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Topic: CREST Pro 9001 - 4 ohm performance
Posted By: ReubGold
Subject: CREST Pro 9001 - 4 ohm performance
Date Posted: 16 February 2017 at 11:11am
Friend been using one of these for years, to power 4x Scoops.

Depending on building power, sometimes great, sometimes OK.

Recently borrowed Crown 5000VZ, and couple of other lightweights to compare.

They all achieved better SPL on average, than the 9001. Confused

Recently read amp has 10KVA transformer, so that means you only really get full performance at 2 ohms stereo?


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If he turns me into a zombie, first person I'm coming after is you.



Replies:
Posted By: Aurora
Date Posted: 16 February 2017 at 11:15am
The 9001 likes a stiff 32amp supply for full performance, you can get away with using it on 4ohm on a 13amp plug but won't full reach full potential, the Crown is a bit more forgiving if you have to use 13amp sockets.


Posted By: levyte357-
Date Posted: 16 February 2017 at 11:21am
I've seen Crest 9001 on stiff 32A supply, powering 4x cabs many times,  and amp was always clipping before drivers were fully powered.

Spec says 2kwpc @ 4 ohm, which lines up, with what I've seen.

Inf8MK2 on 32A, at 4 ohm stereo, could easily have sent the voice coils into the upper stratosphere.
In fact, it is like that on decent 13A supply.




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Global Depopulation - Alive and Killing.


Posted By: Dub Specialist Sound
Date Posted: 16 February 2017 at 11:51am
Disagree man

9001 been benched way exceed the stated specs, i know diff when acually driverinf drivers,

but Crest has allways been conserative with spec power, heard it excells on 64a , 

dont know never tryed it


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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...


Posted By: Dub Specialist Sound
Date Posted: 16 February 2017 at 11:53am
Load them Crest up man, thats what tha built for, 

no mickey mouse




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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...


Posted By: levyte357-
Date Posted: 16 February 2017 at 12:08pm
Originally posted by Dub Specialist Sound Dub Specialist Sound wrote:

Disagree man

9001 been benched way exceed the stated specs, i know diff when acually driverinf drivers,

but Crest has allways been conserative with spec power, heard it excells on 64a , 

dont know never tryed it


Would agree, at 2 ohm it must be mad on big power.

But time after time, seen sounds playing 9001, 1850s, 4 ohm stereo, on 32A at GP, and amp was clipping, long before 1850s were in trouble.

Inf8mk2, even on 13A supply, can have 2x 1850s per channel in trouble.


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Global Depopulation - Alive and Killing.


Posted By: logsquared1
Date Posted: 16 February 2017 at 2:44pm
Originally posted by ReubGold ReubGold wrote:


Recently borrowed Crown 5000VZ, and couple of other lightweights to compare.

They all achieved better SPL on average, than the 9001. Confused

Something is wrong with the 9001.  Possible the high side of the class H circuitry is not working.  The amp will still work it will just clip at half the rail voltage.

The 5000vz and the 9001 have very similar max rail voltages.  IIRC, the 5000 is about 144V peak and the 9001 = 150Vp.  Therefore they should put out very close SPL with the crown a little lower (probably unnoticeable).

I have owned over 8 MA5000's and 10 9001's.   I still use the 900'1's weekly in three different club installs. 

The crown does have a more aggressive sound (distortion).

My personal experience is the crowns are pieces of shit.   Almost all of the ones in my inventory failed multiple times.  Luckly, crown was only 20 min from my shop.  After the 3 year warranty was up they all got sold.

The OPEP circuitry was crown marketing hoopla meaning we are going to put in less transistors than needed and put a protection circuit in to keep them from blowing up.   

The MA2400 and lower were great amps.  The MA3600 = utter garbage.  Once a crown engineer told me they tried to get the company to not release the 3600.  They did anyway.

The 9001 is a real workhorse.  I have run at 2 ohms in a pinch many times no problem.  In 15 years I have only had two failures out of 10 amps.  What you get in performance you pay for in weight. 


Posted By: B_Bender
Date Posted: 16 February 2017 at 2:48pm
how does the plug its got on the end make a difference to the amps performance? surely just the supply voltage on these older amps?


Posted By: Sinai Sound
Date Posted: 16 February 2017 at 3:01pm
Consider that the average impedance of 2 scoops per side isn't really 4ohm

Those with a Powersoft K series DSP will know what I mean

With 4 x PD1852 in polar scoops, that's about 3.5 ohm average 

I'd personally try all 4 on one side of the 9001 to see what it sounds like




Posted By: MarjanM
Date Posted: 16 February 2017 at 3:10pm
Lev, pushing 100-200W per box more will gain you like 0.3db at a risk of burning coils.
Need more sub? Bring more boxes.



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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: levyte357-
Date Posted: 16 February 2017 at 3:13pm
Yes, "on average", 8 ohm can be realistically 10-12 ohms.

However, I've personally witnessed a number of times, Void Infinite 8Mk2, with 2x 1850 cabs per channel, outplay 9001 doing the same thing.

Would agree, on real stiff 32A supply, 9001 with 4x cabs per channel, would probably outplay same on Inf8MK2, but 2x cabs per channel, the Void is definitely exceeding it's 2400wpc spec.

Think the problem is, 9001 PSU efficiency, and really, really stiff mains supply needed, even if only driving 2x cabs per channel.


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Global Depopulation - Alive and Killing.


Posted By: levyte357-
Date Posted: 16 February 2017 at 3:15pm
Originally posted by MarjanM MarjanM wrote:

Lev, pushing 100-200W per box more will gain you like 0.3db at a risk of burning coils.
Need more sub? Bring more boxes.



We're comparing  2x cab per channel performance of 9001, and other amps.

Please leave out the irrelevances.


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Global Depopulation - Alive and Killing.


Posted By: MarjanM
Date Posted: 16 February 2017 at 3:30pm
How is that irrelevant?

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: bass*en*mass
Date Posted: 16 February 2017 at 3:49pm
hmm, in my simple mind its logical, an amp thats designed to provide max. power at say 4ohm will beat an amp designed for max. power at 2ohm on same supply and impedance, on stronger supply the latter will most likely exceed the other amps output on low impedance as its designed to draw more current/work safely at low impedances? (psu, fets quality/amount, "design/layout")





Posted By: MarjanM
Date Posted: 16 February 2017 at 3:55pm
It would be like that if all things are equal. But let the amp limiter release a little bit more power and you gain like 2-3% more THD and presto, you have way louder sounding amp.

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: bass*en*mass
Date Posted: 16 February 2017 at 4:23pm
yep, i agree..
i must say i quite like the "dry" controlled sound of the K10s for example..

after all it is and will always be horses for courses lol, gladly "sound" is very subjective :)
would be boring if we all had the same opinion..





Posted By: MarjanM
Date Posted: 16 February 2017 at 4:33pm
All true, i just want people to know the facts. That amp with just a little more distortion will sound louder, dough it actually isnt.

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Earplug
Date Posted: 16 February 2017 at 7:44pm
Originally posted by MarjanM MarjanM wrote:

All true, i just want people to know the facts. That amp with just a little more distortion will sound louder, dough it actually isnt.


Yup. Crest soft-clip is very good - cuts out the distortion.




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Earplugs Are For Wimps!


Posted By: kedwardsleisure
Date Posted: 16 February 2017 at 8:03pm
Quote how does the plug its got on the end make a difference to the amps performance


It doesn't. The mains will always give as much as the amp needs until the fuse or breaker goes.



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Kevin

North Staffordshire



Posted By: toastyghost
Date Posted: 16 February 2017 at 8:25pm
Originally posted by kedwardsleisure kedwardsleisure wrote:

Quote how does the plug its got on the end make a difference to the amps performance


It doesn't. The mains will always give as much as the amp needs until the fuse or breaker goes.



Yep. Whether the voltage remains constant is a different matter but if you're on a 13 amp plug and you're not tripping a breaker or blowing a fuse, you aren't pulling more than the breakers trip point. It doesn't matter if the connection hung from say a 32 amp B curve breaker is a bank of 13a sockets or a 32a ceeform - the former you just have an extra fuse to consider and if that doesn't blow then you're not pulling more.

But we'll get into this distortion argument again without people understanding that certain order harmonics are often desirable for certain sounds, including perceived loudness.


Posted By: nickyburnell
Date Posted: 16 February 2017 at 11:36pm
Quote

But we'll get into this distortion argument again without people understanding that certain order harmonics are often desirable for certain sounds, including perceived loudness.[/QUOTE]


Yep, 100%.  But to add to that, the holy grail of flat response really isn't what any form of EDM is about, that's for hi-fi or nerds, or people that only listen to classical.......IMHO


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It's everything, not everythink!


Posted By: ceharden
Date Posted: 17 February 2017 at 12:08am
If you like your sound clean and accurate, go Crest.  If you prefer something more like an arc welder, go Crown.  Simples!


Posted By: B_Bender
Date Posted: 17 February 2017 at 9:04am
Originally posted by toastyghost toastyghost wrote:

Originally posted by kedwardsleisure kedwardsleisure wrote:

Quote how does the plug its got on the end make a difference to the amps performance


It doesn't. The mains will always give as much as the amp needs until the fuse or breaker goes.



Yep. Whether the voltage remains constant is a different matter but if you're on a 13 amp plug and you're not tripping a breaker or blowing a fuse, you aren't pulling more than the breakers trip point. It doesn't matter if the connection hung from say a 32 amp B curve breaker is a bank of 13a sockets or a 32a ceeform - the former you just have an extra fuse to consider and if that doesn't blow then you're not pulling more.

But we'll get into this distortion argument again without people understanding that certain order harmonics are often desirable for certain sounds, including perceived loudness.

Originally posted by levyte357- levyte357- wrote:

I've seen Crest 9001 on stiff 32A supply, powering 4x cabs many times,  and amp was always clipping before drivers were fully powered.

Spec says 2kwpc @ 4 ohm, which lines up, with what I've seen.

Inf8MK2 on 32A, at 4 ohm stereo, could easily have sent the voice coils into the upper stratosphere.
In fact, it is like that on decent 13A supply.



 

but I don't get how being on a 32a supply seems to be better for the amps performance?


Posted By: m0gsi
Date Posted: 17 February 2017 at 10:40am
A 32a socket is likely to be wired to the building incoming electricity supply with a larger lower resistance cable therefore less voltage drop when the amplifier is drawing high peak current. 




Posted By: B_Bender
Date Posted: 17 February 2017 at 11:13am
Originally posted by m0gsi m0gsi wrote:

A 32a socket is likely to be wired to the building incoming electricity supply with a larger lower resistance cable therefore less voltage drop when the amplifier is drawing high peak current. 

I see.....! But wouldnt a ring main be wired with cable to supply 30+ amps, that's only two double sockets worth of power


Posted By: toastyghost
Date Posted: 17 February 2017 at 11:24am
Originally posted by B_Bender B_Bender wrote:

Originally posted by m0gsi m0gsi wrote:

A 32a socket is likely to be wired to the building incoming electricity supply with a larger lower resistance cable therefore less voltage drop when the amplifier is drawing high peak current. 


I see.....! But wouldnt a ring main be wired with cable to supply 30+ amps, that's only two double sockets worth of power


Yes. Often on the same DB. Side by side with your magic 32a feed using the same breaker.

Also I can't remember the last event I went to of ANY kind where the show ran with a flat response. Maybe from 1KHz up at most.


Posted By: kedwardsleisure
Date Posted: 17 February 2017 at 1:18pm
If your 13A outlet is dropping enough voltage to be audible on the output of an amplifier then something must be getting very hot somewhere.

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Kevin

North Staffordshire



Posted By: B_Bender
Date Posted: 17 February 2017 at 1:21pm
Originally posted by Dub Specialist Sound Dub Specialist Sound wrote:

but Crest has allways been conserative with spec power, heard it excells on 64a
Originally posted by levyte357- levyte357- wrote:

Inf8mk2, even on 13A supply, can have 2x 1850s per channel in trouble.
Originally posted by Aurora Aurora wrote:

The 9001 likes a stiff 32amp supply for full performance

So is this all bollox then?!


Posted By: toastyghost
Date Posted: 17 February 2017 at 1:51pm
In a nutshell, yes. Unless the people using them on 13A sockets are tripping breakers or blowing fuses.


Posted By: luton_soundman
Date Posted: 17 February 2017 at 4:07pm
Just dont use a fuse on your bass amp/s ...

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Sound Hire/Sales new/used equipment.


Posted By: B_Bender
Date Posted: 17 February 2017 at 4:29pm
Originally posted by luton_soundman luton_soundman wrote:

Just dont use a fuse on your bass amp/s ...

LOL dear oh dear


Posted By: toastyghost
Date Posted: 17 February 2017 at 4:45pm
Originally posted by B_Bender B_Bender wrote:

Originally posted by luton_soundman luton_soundman wrote:

Just dont use a fuse on your bass amp/s ...


LOL dear oh dear


Yeah but NO. Just use the right fuse type. If you're popping slow curve 13a fuses you're in danger of melting the socket already. Don't be an idiot.


Posted By: luton_soundman
Date Posted: 17 February 2017 at 5:06pm
Nice bit of copper

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Sound Hire/Sales new/used equipment.


Posted By: toastyghost
Date Posted: 17 February 2017 at 5:21pm
Originally posted by luton_soundman luton_soundman wrote:

Nice bit of copper




You can pull 25 amp current for a full non-stop 30 minute period on a proper a 13 amp fuse before it blows. If you need more than that, you need to reconsider your rig setup. Bring more amplifiers, or less rig.


Posted By: nickyburnell
Date Posted: 17 February 2017 at 5:28pm
Originally posted by toastyghost toastyghost wrote:

In a nutshell, yes. Unless the people using them on 13A sockets are tripping breakers or blowing fuses.





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It's everything, not everythink!


Posted By: luton_soundman
Date Posted: 17 February 2017 at 5:41pm
Jheeze just abit of banter.

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Sound Hire/Sales new/used equipment.


Posted By: mini-mad
Date Posted: 17 February 2017 at 6:45pm
Originally posted by luton_soundman luton_soundman wrote:

Jheeze just abit of banter.


...so the foil in a fag packet is out the question then...?





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If it sounds like a gorilla is trying to escape, turn it down.


Posted By: ceharden
Date Posted: 17 February 2017 at 11:35pm
I installed a 9001 in a venue many years ago.  It was wired onto a 32A supply, with something like only 3m of cable, mostly 10mmsq back to the main incomer for the building.

You can get noticable Voltage drops on on supplies in some venues.  In another one I used to work in a long time ago, the bass amp would trip out when the fridges turned on and the desk lamp on the mixer used to flash in time to the beat....

In an ideal world, the supply you're connected to wouldn't matter but sometimes on an older installation or one that's not quite been designed/spec'd properly, it can make a difference.

Running outdoors, potentially on long feeders (under-sized for the length) I've often watched the Voltmeter on the distro bouncing to the beat, sometimes by an alarming amount.




Posted By: sajti
Date Posted: 18 February 2017 at 6:08am
We did a relatively big show in the middle of nothing, at a little village. The village has a beautiful 300 years old church, and the major wants to collect some money, to renovate it.
We get the powerdirectly from the central transformer house, which was feed the whole village, 3 phase, 3x63A was the rated power. We used Crest amplification many 8001s for bass, 7001s, and 4601s.
Everything was OK during the soundcheck, but when we started the concert we faced with the problem, that all lights in the village was dimming with the beat of the bass. Even the public lights on the street too. Shocked All amps are clipped heavily, so I have to turn down the whole system with about 4dB.

Sajti



Posted By: B_Bender
Date Posted: 18 February 2017 at 10:01am
just because the plug is blue or red and says 63a, doesn't mean the supply's up to it.


Posted By: Earplug
Date Posted: 18 February 2017 at 5:18pm
Also, it's not just the ring main capacity, but the contact area and resistance of the plug. A 13A plug has a certain surface area, calculated to safely supply 13A and not 32A. I don't have any UK plugs here, so maybe some volunteer can measuring the contact area for us?  LOL 

Ceeforms obviously give more contact surface, so safer. I´ve seen a fire destroy a building because the local sparky was a bit lazy and didn't fully tighten up the terminals on the feed he gave us for a gig. The contacts overheated and bang. End of the place. I've also seen a 16A Schuko after a few evenings powering 4 x 1k PAR 64's. Not pretty.




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Earplugs Are For Wimps!


Posted By: MarjanM
Date Posted: 18 February 2017 at 5:25pm
We have blown 100A fuses more then once ;-)

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Marjan Milosevic
MM-Acoustics
www.mm-acoustics.com
https://www.facebook.com/pages/MM-Acoustics/608901282527713


Posted By: Earplug
Date Posted: 19 February 2017 at 9:34am
Originally posted by MarjanM MarjanM wrote:

We have blown 100A fuses more then once ;-)


You've put M4 bolts in the fuse of a 13A UK plug?!?    LOL  Shocked  LOL




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Earplugs Are For Wimps!


Posted By: Father-Francis
Date Posted: 19 February 2017 at 10:18am
Originally posted by MarjanM MarjanM wrote:

We have blown 100A fuses more then once ;-)

Is this a brag about who blows the biggest fuse ,

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Music is the strongest form of magic.(+45 31879997)blakmanpro@gmail.com, foa@sweetboxaudio.dk


Posted By: jammin75
Date Posted: 19 February 2017 at 10:06pm


blow sum of these LOL

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feel the vibes !!!   "Who Feels it Knows it"            Strong like Lion              



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