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Author Topic: adavantage?  (Read 17797 times)

Berti Jacobs

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adavantage?
« on: December 28, 2009, 12:37:53 pm »

Hello everybody,

I'm in the process of building 8 LAB's (4 per side)
I'm wondering whats the better way to power them:
1 Itech 8000 per 4 LAB's  or  2 Itech4000 per 4 LAB's ??

thanks for any advice

Berti
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Art Welter

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Re: adavantage?
« Reply #1 on: December 28, 2009, 04:52:26 pm »

Berti,

The Lab Sub with the speakers in parallel is roughly a 4 ohm load.

I-T 8000 can deliver 3500 watts/4 =875, so it is adequate in that it has more than double the RMS rating of a Lab 12 speaker.

However, the I-T amps are current limited at 2 ohm operation, and put out less power at 2 Ohm than 4 ohm, so a pair of I-T 4000 at 4 ohm would deliver a bit more power without limiting than an I-T 8000 loaded to 2 ohm.
Current limited power generally does not sound so good as straight power, I would not want to use an amp that is current limiting under “full tilt” use.

If you are looking for a single amp for 4 Lab subs, you should look for something rated for more power at 2 than 4 ohms.index.php/fa/27089/0/

Art Welter
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Elliot Thompson

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Re: adavantage?
« Reply #2 on: December 29, 2009, 02:44:04 pm »

Berti Jacobs wrote on Mon, 28 December 2009 17:37

Hello everybody,

I'm in the process of building 8 LAB's (4 per side)
I'm wondering whats the better way to power them:
1 Itech 8000 per 4 LAB's  or  2 Itech4000 per 4 LAB's ??

thanks for any advice

Berti




Two amplifiers are always better than one from a longevity standpoint. Many amplifiers claim they can deliver 2-ohms per channel however, how long is not guaranteed.

If you are looking for worry free results, buy two amplifiers, use them at 4-ohm per channel than, trying to extract every ounce of reserve energy from one amplifier loaded in a 2-ohm per channel load.

Best Regards,
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Elliot

jeffhtg (Jeff Kenney)

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Re: adavantage?
« Reply #3 on: February 10, 2010, 12:01:13 am »

Elliot Thompson wrote on Tue, 29 December 2009 19:44

Berti Jacobs wrote on Mon, 28 December 2009 17:37

Hello everybody,

I'm in the process of building 8 LAB's (4 per side)
I'm wondering whats the better way to power them:
1 Itech 8000 per 4 LAB's  or  2 Itech4000 per 4 LAB's ??

thanks for any advice

Berti




Two amplifiers are always better than one from a longevity standpoint. Many amplifiers claim they can deliver 2-ohms per channel however, how long is not guaranteed.

If you are looking for worry free results, buy two amplifiers, use them at 4-ohm per channel than, trying to extract every ounce of reserve energy from one amplifier loaded in a 2-ohm per channel load.

Best Regards,



unless your talking about powersoft..
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Gary Perrett

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Re: adavantage?
« Reply #4 on: February 11, 2010, 11:29:45 pm »

Ya... ain't that a bitch Laughing  Laughing  Laughing We have run 6 labs, 3 per side off a Digam 5000 INSANE output and NEVER a failure in 3 years of outdoors shows. This was for playback of music files on a lazer light show... did a show with a big outdoor stage and bands with a JBL rig with 4 JBL 4719's per side with each cab running off a Mac 5002VZ... that's 16, 18" woofers with 40,000 watts of crown power... couldn't even hear his system when the block of 6 labs was running...HE WAS SO PISSED...that was BEFORE he came over to see what was driving the labs...THAT sent him over the edge!
G
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Elliot Thompson

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Re: adavantage?
« Reply #5 on: February 12, 2010, 01:38:03 pm »

jeffhtg (Jeff Kenney) wrote on Wed, 10 February 2010 05:01

Elliot Thompson wrote on Tue, 29 December 2009 19:44

Berti Jacobs wrote on Mon, 28 December 2009 17:37

Hello everybody,

I'm in the process of building 8 LAB's (4 per side)
I'm wondering whats the better way to power them:
1 Itech 8000 per 4 LAB's  or  2 Itech4000 per 4 LAB's ??

thanks for any advice

Berti




Two amplifiers are always better than one from a longevity standpoint. Many amplifiers claim they can deliver 2-ohms per channel however, how long is not guaranteed.

If you are looking for worry free results, buy two amplifiers, use them at 4-ohm per channel than, trying to extract every ounce of reserve energy from one amplifier loaded in a 2-ohm per channel load.

Best Regards,



unless your talking about powersoft..



Powersoft is just like any other amplifier. The only magic is the marketing. Smile

Best Regards,
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Elliot

Nathan Short

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Re: adavantage?
« Reply #6 on: February 15, 2010, 12:34:15 pm »

Powersoft K10dsp is the only amp I have torture tested that will put out a continuous 50hz sine wave minute after minute  @ 76v per output, off a 20 amp circuit.

Damn hard to find another amp that can do that.  

Not magic, just damn fine engineering.  
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Elliot Thompson

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Re: adavantage?
« Reply #7 on: February 15, 2010, 04:20:28 pm »

Nathan Short wrote on Mon, 15 February 2010 17:34

Powersoft K10dsp is the only amp I have torture tested that will put out a continuous 50hz sine wave minute after minute  @ 76v per output, off a 20 amp circuit.

Damn hard to find another amp that can do that.  

Not magic, just damn fine engineering.  



I don't see the logic trying to operate an amplifier designed to deliver 12,000 watts on a 20-amp circuit more so feeding it a 50Hz sine wave.

I hope you know 76 volts only brings forth the following wattage:

76 volts @ 8 ohms = 722 watts

76 volts @ 4 ohms = 1444 watts

76 volts @ 2 ohms = 2888 watts

If you would like to believe you are going to attain more than that on a 20-amp circuit longterm you have a right to your own opinion. However, the ohms law states otherwise.   Cool

Best Regards,
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Elliot

Nathan Short

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Re: adavantage?
« Reply #8 on: February 15, 2010, 05:58:57 pm »

Oops,

I just went back over my notes The powersoft had to go back to an old business partner before I did round 2 of my last 2 weeks of torture testing.

The Powersoft K10dsp would max out at 67v drawing an average of 26amps @ 50Hz near input limit

PL380 60v drawing 29 amps consistantly.  

Those were the only 2 real sub amps I tested, the rest were a range of 4 OEM new amps of varying topology.  PL340, crown 3600, PL3602, and RMX 2402.

Detailed notes about voltage and current draw over time, were taken at Pink 6db crest, 30Hz, 50Hz, 1k, 15k, Dance Music, Dance Music into hard limit.

Power was supplied 100amps in from the wall, into a custom Military Server Farm Surge supressor with current meter, out to amplifiers through a heavy duty 20amp outlet wired to heavy 10 guage cable.

Amps were wired into a heavy resistor bank, and water heater bucket at alternating tests.

The most interesting thing was finding a flaw in the PLX3602 that at 30Hz and 15K  channel 2 would behave normally and channel 1 would try and put out 81v!!!  Danger Danger!  and the amp would go into overdrive and try and pull 33amps from the wall.  All in all, I got all the info I needed, and a good refresher course on amp layouts with a little help from Fred Merkle.  

My point being, that Powersoft to me was able to do the most, for longer, than any other brand.  

New Crown was not invited to the test, as I don't care for it.

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Elliot Thompson

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Re: adavantage?
« Reply #9 on: February 16, 2010, 09:32:05 pm »

Nathan Short wrote on Mon, 15 February 2010 22:58

Oops,

I just went back over my notes The powersoft had to go back to an old business partner before I did round 2 of my last 2 weeks of torture testing.

The Powersoft K10dsp would max out at 67v drawing an average of 26amps @ 50Hz near input limit

PL380 60v drawing 29 amps consistantly.  







Upon reading your review, it seems the K 10 current limit itself from drawing more amperage even though the line source was not the limiting factor.

67 volts using a dummy load would yield:

571 watts @ 8 ohms

1122.25 watts @ 4 ohms

QSC introduced a white paper on the PL 380 (in addition to the lower wattage models) that states 30 amperes is to be expected long term so, 29 amperes is not surprising.

60 volts would bring forth the following results:

450 watts @ 8 ohms

900 watts @ 4 ohms

Using the wattage versus dB equation (60 volts versus 67 volts), you would achieve a 0.7 dB gain.

I would imagine the user would determine which option is best for his or her needs.

Personally, I rather have an amplifier that chokes based on not enough current from the receptacle than, one that limits itself when there is more than enough current available. I do not own any Class D amplifiers as of yet so, it is always good to hear how they compare amongst one another.

Best Regards,

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