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Need some advice...please!


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#1 zorp

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Posted 18 May 2006 - 08:22 AM

We have 12X EAW KF850's and 8XSB850's. We want to switch over to IT's or MA amplifiers to power them up. Can anyone advice me as to how many amps i would need and the best wiring solution?

#2 zorp

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Posted 30 May 2006 - 03:22 AM

sad.gif  42 views and no replies...no one??? We have been using Macrotec amps for over 5 years with a 0 failure rate...the only issue i have against them is they weigh too much. I have heard of some reliabilty issues with the I Tec series under hot and dusty conditions(similar conditions prevail in this country). Has anyone heard of I-Tecs failing under similar conditions.

#3 DGlass

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Posted 30 May 2006 - 03:04 PM

Sorry we don't keep the power specs for every speaker device out there and with out that and your wiring scheme to calculate impedances well...........  smile.gif
However, if you follow the guidelines provided in previous postings of this forum on amplifier selection or the EAW white paper on amplifier power it should be an easy number to figure out.
As for reliability issues you are mentioning I can't say we have any reports of that happening. The I-Techs have dust filters and, as with any amp, if you keep them clean you shouldn't have a problem. If the filters get blocked you will have no air flow, no air flow = no cooling and the amp will thermal at some point no matter what the ambient temperature is.
You don't say how hot or the conditions the amplifiers are being asked to work in but if the ambient temperature is 120 degrees F/49 C (like I hear it can get in Oman on a summer afternoon ohmy.gif ), and the amps are in black racks that are sitting in the sun and the filters are plugged with dirt...than you will have trouble with anything electronic.
With reasonable conditions and expectations the I-Techs should have no problem in any condition a human being can handle. smile.gif

#4 zorp

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Posted 31 May 2006 - 01:33 AM

Hi David,

Thanks for the advice. I just thought there might be users here who own an inventory of EAW KF's and IT's or MA's. You are right about the temperature in Oman, 49C is pretty regular and it shoots up even higher. We currently use MA3600vlz to power up our subs and a combination of different XS amplifiers to power the tops. We have had some problems with the latter. We have noticed that a number of our amps just switch off with only the ac power led lighting up. The only way to get them up and running again is to reset them(using the reset switch at the back). This happens without the amp peaking. It could not be the heat because we have never used these in the extreme temperatures(outdoor in summer). I would appreciate your insight into this.  I understand these amps are not designed for touring, which is why we want to shift to IT's or MZ's. MA's rock! Needed to clarify that the IT's offer the same degree of reliability(being SMPS and Digital).

#5 DGlass

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Posted 31 May 2006 - 02:35 PM

QUOTE(zorp @ May 31 2006, 01:33 AM)
Hi David,

Thanks for the advice. I just thought there might be users here who own an inventory of EAW KF's and IT's or MA's. You are right about the temperature in Oman, 49C is pretty regular and it shoots up even higher. We currently use MA3600vlz to power up our subs and a combination of different XS amplifiers to power the tops. We have had some problems with the latter. We have noticed that a number of our amps just switch off with only the ac power led lighting up. The only way to get them up and running again is to reset them(using the reset switch at the back). This happens without the amp peaking. It could not be the heat because we have never used these in the extreme temperatures(outdoor in summer). I would appreciate your insight into this.  I understand these amps are not designed for touring, which is why we want to shift to IT's or MZ's. MA's rock! Needed to clarify that the IT's offer the same degree of reliability(being SMPS and Digital).
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MA amplifiers have a circuit called ODEP. If under extreme operating conditions, more power is required than the output devices are capable of delivering, because of the thermal state of the output devices, ODEP will limit proportionally the drive output in small increments. ODEP will not shut down the amplifier, although if conditions are extremely severe it can almost completely limit the audio to prevent damage. ODEP will produce a hash limiting sound when working but the show goes on.
The XS series use a thermal sensor circuit that will shut off the amp should the amp exceed its internal thermal operating range. There is also a transformer thermal sensor. Your situation, with these amps, may be that your transformer thermal sensors are a bit to sensitive for some reason (or it may be something completely different). This would have to be verified by our distributor's service center there.
The ITechs have a last resort thermal cut off for the power supply and the outputs. However, we have never seen this be an issue as the Internal Thermal cut off is in the neighborhood of 90 C. ohmy.gif
ITechs also have a TLC circuitry that would have started to kick in long before the thermal cut off happened. TLC unlike ODEP doesn't have that harsh ODEP limiting sound. The TLC protection system will subtly and dynamically reduce gain, only when absolutely required, to reduce heat build-up. So the show will go on until the amp just cannot do anymore.
I am told by our lead ITech engineer that we have done thermal runs, in our environmental chamber, at 40 C and the I-Techs were still going. He also said that he would expect better high temperature performance from the I-Techs than even the MAs. smile.gif

#6 schnakesound

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Posted 01 June 2006 - 02:48 PM

Hi David,

It sounds as if you have a nice EAW rig.  It simalar to mine.  There are two ways you can go that I would suggest.

1) MA Series Amps -  This is amp set up that I have been using.

1 5002vz for every 4 cabinets.  This will run the amps at 2 ohm a side in stereo with 750 watts to each speaker in each cabinet.  This will take care of the SB850 subs and they will sound great.

I also use for every four tops I tri-amp using 1 MA1200 on horns, 1 MA2402 on mids and 1 3600vz on the low.  This is ran with the amps in stereo and a 4 ohm load on each amp. smile.gif   So to run this type of system you would need 3 x MA1200, 3 x MA2402, 3 x
3600vz and 3 x 5002vz.  This rig sounds great.

I am moving to the iTECH myself and plan to run for every 4 KF850 tops and every 4 SB850 subs the following:

1 - XTi 1000 for horns
1 - XTi 4000 for mids
1 - iTECH 4000s for lows
2 - iTech 6000s for subs

You would need the above x 3 in order to meed the specs for the EAW 850s and using the 1.5 x power recomendation from EAW.

Hope this helps.

Bill Schnake
Schnake Sound  smile.gif
Roll it in...Hook it up...Make some magic.

Visit us at: http://www.schnakesound.com

Bill Schnake