Amplifier suggestions

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#1 storm02guitar

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Posted 03 March 2006 - 11:27 PM

I'm just starting out buying my own equipment here for a gigging band and needed some advice. Right now I have 4 Peavy Black Widow 18" subs running 700 watts program at 8 ohms and then 2 EV T221s that run 1,600 watts peak, 400 watts continuous LF at 8 ohms and 60 watts continuous HF at 8 ohms.

I would like to buy amps that could run these now and then function to power speakers that I would upgrade to in the future. The speakers that I'm looking at upgrading to are EV MTL-1Xs running 1200 watts continuous, 2000 program and 4800 max at 4 ohms and EV QRx 153/75s that run 400 continuous - 1600 watts max LF at 8 ohms and 150 continuous - 600 watts max HF at 12 ohms.

So I'm looking for a HF amp, a LF amp, and an amp for my subs. I was trying to decide between the new XTi series and the I-Techs, but if you have other suggestions I would be open to them as well. How does this sound: a XTi 4000 for the HF, an I-Tech 4000 for the LF, and I-Tech 6000s for the subs? Thanks for any advice you can give me.

#2 Bud Bolf

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Posted 11 March 2006 - 09:38 AM

  I'll take a crack at this.
Right now I have 4 Peavy Black Widow 18" subs running 700 watts program at 8 ohms

OK you have four 18" Black widows rated at 700 watts RMS at 8 ohms.
What kind of cabs are these? Single 18's, Dual 18's?
If they are single 18's then I would parallel two cabs together.
This would get you to a 4 ohm load at 1400 watts.
Per two 18's you would want between 2100 to 2800 watts RMS / Continuous.
This is based on a formula of 1.5 to 2x the speakers RMS / Continuous rating for a Power Amp.
Read this:How Much Power do I need?
If they are dual 18's and already at 4 ohms the power need would be the same.
You have many choices to get 2100 to 2800 watts of power.
You could do this with an amp per channel at 4 ohms and in this range.
You could do this with a Bridged Power Amp that gets you in the ballpark as well.

1) An I-Tech 4000 would let you power two 18's per channel at 2000 watts per channel at 4 ohms.
2) Two CE4000's Bridged at 2800 watts at 4 ohms would work with 1 amp per pair of 18's.
3) Two XS900's Bridged per pair of 18's would net you 2500 watts at 4 ohms.

As you can see once you know the amount of Power Amp Watts needed, then
just go shopping. I try and stay on the 2x ratio with Subs, but anywhere
in between should be OK.

then 2 EV T221s that run 1,600 watts peak, 400 watts continuous LF at 8 ohms and 60 watts continuous HF at 8 ohms.

Low Frequency first.
400 watts at 8 ohms.
With the Ratio discussed above of 1.5 to 2x Power Amp to speakers,
that would mean that you would need between 600 to 800 watts per Speaker.
Once again you could do this per Channel or Bridged.
You could also leave the Low Freq. speakers at 8 ohms or parallel the two LF speakers to get to 4 ohms.
You can run your top cabs Mono or Stereo. Decisions Decisions Decisions!
If Stereo then you want a Power Amp to run your Low Frequency speakers per Channel at 8 ohms.
The I-Tech's have too much power for your Low Frequency speakers.
1) An XS900 is rated at 600 watts per channel at 8 ohms.
2) A CE4000 is rated at 600 watts per channel at 8 ohms as well.
though I'd probably opt for the XS900 rather than the CE4000.
3) The new XTi 4000 puts out 650 watts per channel at 8 ohms.

Is a different story, you need 600 to 800 watts at 4 ohms because the two
Low Frequency drivers will be Paralleled together.
You could actually put the Low Frequency speakers on one channel at 4 ohms.
Unfortunately your High Frequency drivers are only rated at
60 watts at 8 ohms, which means that you only need 90 to 120 watts to power them.
You said:
a XTi 4000 for the HF

You were thinking of putting 650 watts on the High Frequency drivers?
Talk about Over-Powering!
You can't put the HF on the same amp that the LF is on, so you might as well run the LF and HF in Stereo.
Find an amp for the Low Frequency rating of 600 to 800 watts at 8 ohms.
Find an Amp for your High Frequency drivers of 90 to 120 watts per channel at 8 ohms.

You have read this correct:EV T221 PDF EDS Sheet

Second part of your question on upgrading later:
The EV MTL-1Xs wants between 1200 and 1680 Watts per cab at 4 ohms.
The I-Tech at 2000 watts per cab would be a tad over the 1680 but would be ok with a Limiter. The specs say that it can be powered between 2 to 4x the 1200 watts for experienced Sound Engineers.
As far as the EV QRx 153/75s from what I can see the Bi-amp power looks
ok, you might want to call Tech Support at EV and see what has worked well for these cabs as I am not familiar with them and do not want to overstate my advice.
You can also check over at PSW, you might find some people that actually use these cabs.
The Link is here: Pro Sound Web