How much power do I need for two 800W cabs (8 ohms each)

#41
I'm using a single 410 cab rated at 1400-watts rms @ 8ohms. I'm running an Eden WT500/800 (upgraded to 800-watts rms bridged at 8 ohms) into it and rarely run the master above 9:30 because it's just too darn LOUD! With that master volume setting I am running no where near the 800 watts my amp will put out, let alone the 1400 rms watts that the speaker cab can handle. So like it was said in one of the responses earlier, you "probably" don't need to have a 1600 watt amp for your two cabs with their 800-watt "power-handling" rating.

The nice thing about having an amp that will put out more power than you need (even though it won't max out my cab) is that running it at 1/4 to 1/3 power puts little strain on it and it runs a lot cooler than a less powerful amp running close to max for the same volume. So there is something to be said about having plenty of watts. More important would be to make sure your amp can run a 4 ohm load (almost all modern amps can), since two 8 ohm cabs hooked up in parallel create a 4 ohm load.

My guess would be that as long as you have an amp that puts out about 800-watts rms, you'll probably be fine. You could go with one that puts out 1600-watts - enough to run both cabs to max - but odds are you'll never use a fraction of that power.

If you think you really need a LOT of power and a lightweight amp, check out the DNA (David Nordschow Amplification) 1350 amp, which will give you 1350-watts into a 4 ohm load while weighing in at just 7-lbs.
 
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#42
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#43
/\/\3phist0 said:
You want to win volume wars and sound great at the same time? Mesa TITAN
MESA/Boogie®
  • 1200 Watts @ 4 Ohms (840 Watts @ 2 Ohms, 650 Watts @ 8 Ohms), Simul-State™ Power w/ 4 or 2 Ohm Impedance Select Switch for optimum Power/Load Performance / 22 Tube driven Power MOSFET’s, 4x12AX7
  • Active/Passive Input Switch
  • 2 Fully Independent Footswitchable Channels featuring Gain, Active Bass, Passive Mid, Active Mid w/Mid Frequency Control (adjustable from 200 Hz to 2 kHz), Active Treble, Master Volume, Footswitchable Tube Over Drive & Over Drive Level Controls
  • Two Instrument Inputs (A or B) with Input Selector Switch (A, B or Footswitch), which allows you to plug 1 instrument into Input 1 and footswitch between the 2 Channels or plug 2 separate instruments into Inputs 1 & 2 and route them to their own corresponding, optimized preamp channel for seamless live transitions
  • Output Level Control (over all channels)
  • Footswitchable Solo Level Control – Patent 6,724,897 (over all channels)
  • FX Loop w/True “Hard” Bypass Switch (over all channels when activated)
  • Front & Rear Panel Tuner Outputs with Footswitchable or Front Panel Amplifier Mute/Standby Control
  • Balanced XLR Line Out with Pre/Post Switch, Level Control & Ground Lift
  • External Switching
    Jacks for Channels 1 & 2, Over Drive Channels 1 & 2, Input Select A & B, Solo & Mute
  • 2 – Speakon - 1/4” Combination Speaker Output Jacks
  • Slave Out w/Level Control
  • Fan Cooled
  • 5-Button Footswitch (Channel 1, Channel 2, Channel 1 Over Drive, Channel 2 Over Drive, Input
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    Big Block Titan V12 Bass Amplifier • 3 Rack Spaces
    Big Block Titan V12 Classic Head • Black Bronco (standard)
Click to expand...

Are you sure you don't have the 2 ohm and 4 ohm ratings on this amp flip-flopped? Never seen a SS amp that will run a 2 ohm load delivering fewer watts than it does with a 4 ohm load. Sounds counter-intuitive.
 
#45
Rip Van Dan said:
The nice thing about having an amp that will put out more power than you need (even though it won't max out my cab) is that running it at 1/4 to 1/3 power puts little strain on it and it runs a lot cooler than a less powerful amp running close to max for the same volume. So there is something to be said about having plenty of watts. More important would be to make sure your amp can run a 4 ohm load (almost all modern amps can), since two 8 ohm cabs hooked up in parallel create a 4 ohm load.
Click to expand...
Common misconception, but the least efficient operating point for a class AB amp (such as with the WT-500/800) is right around 1/3 power. It's the point of highest heat dissipation per watt of audio output power.
 
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#47
Rip Van Dan said:
Are you sure you don't have the 2 ohm and 4 ohm ratings on this amp flip-flopped? Never seen a SS amp that will run a 2 ohm load delivering fewer watts than it does with a 4 ohm load. Sounds counter-intuitive.
Click to expand...
There's a few that do. I had a Yorkville XS800 that ran 600w@8ohms, 800w@4ohms and 600w@2ohms.
 
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#49
Rip Van Dan said:
Are you sure you don't have the 2 ohm and 4 ohm ratings on this amp flip-flopped? Never seen a SS amp that will run a 2 ohm load delivering fewer watts than it does with a 4 ohm load. Sounds counter-intuitive.
Click to expand...
The specs are correct, I understand that this was to allow the amp to limit themal overrun, caused by the additional current, while still allowing the user to run a 2ohm load safely.
 
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#50
BadExample said:
As Andy stated, headroom is the unused amount of wattage rating, so it causes nothing. On an amp its like keeping a good healthy balance in your checking account. Cab headroom might be more like overdraft protection. Neither means its safe to dime all the knobs or write a huge check at the music shop.
Click to expand...

I know what headroom is. I was just stating that you can achieve a certain sound out of an amp with less power if you opt for a lower powered amp in some cases. Some people are not looking for loud and clean
 
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#55
watts is only part of the picture ... amp = headroom , cabs = sensitivity

please protect your ears ..!! from someone who lost 95% hearing in my left ear while in highschool ! (1974)

that said , having some extra power is a good thing ... having to little and then maxing out your power into distorted crap , can harm your speakers ..
 
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#56
Some problems that might be causing this.
1) Your amp has a problem and is not making power like it should.
Test with a different amp of similar power with your speakers.
2) Your speakers may actually be 4 ohms each.
Are you absolutely certain they are 8 Ohm cabs? Have you measured? Don't just believe the lable, unless you bought them new and are 100% sure they've not been modded.
3) Your two cabs are out of phase in relation to each other.
Play your amp into one cab only at a set volume, then without changing volume, play the same way with both cabs connected. They should get louder, if the aren't or they get quieter, you may have a phase reverse problem.
 
#57
DavC said:
that said , having some extra power is a good thing ... having to little and then maxing out your power into distorted crap , can harm your speakers ..
Click to expand...
To large of an amp can just as easily damage speakers, maybe more often than with a smaller amp.
 
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#59
TrevorOfDoom said:
I knew a guy who ran a 1000w head into a 1x12 rated for 300 watts. Worked perfectly for him, just jamming in his living room.
Click to expand...
Sure it's entirely possible, but I have also seen the results of this same thing gone very wrong because the players had no idea they were damaging their speakers from the effects of using too much power (not in a living room though).
 
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#60
Thanks for the replies everyone.

It's not that the 750x "isn't enough", just a few things like having owned it for 10 years, including leaving it in a damp basement where we practiced for months. The gain and volume pots crackle loudly when adjusted, even after having it cleaned, and one of the 2 channel outputs on the back doesn't work anymore, so I kinda fear its a matter of time, + having GAS and the fact that a used Eden WT800 is only like $500....could probably hold out with the 750x a little longer though, considering I'm not really gigging right now -_-
 
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