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

#61
If you were able to find a real tech who knows their stuff, your amp would really be fixed and not just patched together. You might find the same reliability situation with any used amp, such as the one you are looking at.
 
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#64
I think a good tech could repair your 750 for a reasonable fee. It has enough watts, IMO. If you like the way it sounds do that. Otherwise, go for the new amp. Have fun! good luck.

Back in the day I could play pretty much any gig with my Sunn 2000s(120w) and a couple of 2x15 JBL cabs. So having 5 times the amp power is like the new Corvettes streeting 650hp. Fun to have but not the most useful a lot of the time. But hey, I'd buy the Corvette!
 
#66
Munjibunga said:
If he put 800 watts into an 800-watt cab for any length of time, he'd be looking for a new cab shortly thereafter.
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If the cab couldn't handle 800 watts then the 800 watt rating is BS as I suspect are a lot of ratings nowadays. But if it is a real rating it would have no problem handling what it says it will. I have put 300 watts real watts (300 WRMS @< 2% distortion into 4 ohms into a 150 watt RMS 4 ohm cab for years with no problems.
 
#67
bobyoung53 said:
Only with a SS amp, you can overdrive a tube amp all you want (if you stay within the speaker specs) without worrying about your speakers.
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Is it a full moon today or what?

Clipping is clipping, and overdriving a tube amp brings with it the same cautions that overdriving a solid state amp does.
 
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#68
bobyoung53 said:
If the cab couldn't handle 800 watts then the 800 watt rating is BS as I suspect are a lot of ratings nowadays. But if it is a real rating it would have no problem handling what it says it will. I have put 300 watts real watts (300 WRMS @< 2% distortion into 4 ohms into a 150 watt RMS 4 ohm cab for years with no problems.
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So you had the amp cranked to full power? I run 800-watt amps (500w at 8Ω) into 700- and 400-watt cabs all the time, but I never put all 800 or 500 watts into the cab. I'm very doubtful that you could run a cab at its full-rated power for an hour without blowing it up. @agedhorse come in for the smackdown.
 
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#71
Siggy said:
Over driving an lower wattage amp (CLIPPING) will damage speakers. I typically like some headroom in my amps.
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Not necessarily. I run through an amp that is clipping basically all the time. My amp is 180 watts, my cab handles 800. It sounds good, no speaker damage. Also if clipping itself damaged speakers, guitarists would be destroying speakers all the time. It's overpowering that destroys speakers, not whether the signal is clipped.

Damani311 said:
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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So just get your 750 fixed up by a good tech. It'll cost less than $500. Also, why do you want the WT800 so much? Seems kinda meh, to me.
 
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#72
Munjibunga said:
So you had the amp cranked to full power? I run 800-watt amps (500w at 8Ω) into 700- and 400-watt cabs all the time, but I never put all 800 or 500 watts into the cab. I'm very doubtful that you could run a cab at its full-rated power for an hour without blowing it up. @agedhorse come in for the smackdown.
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You just gotta listen to it, if it makes funny noises turn it down. I have run a 150 watt B-15T (15") cab in little rooms with an SVT head and have done so for years with no problems. How do you know if you are running full power at any instant? Output power is instantaneous with a source like a bass guitar, it's only constant with a constant tone like from a signal generator, if you are an exceptionally even player you might be at a fairly constant output most of the time, but more likely your amp could put out anywhere from 0 watts and up and then hit a good loud low E and it's cranked. If you are not playing it's putting out 0 watts, play a loud low B or E and it could be at maximum rated power.
 
#73
bobyoung53 said:
You just gotta listen to it, if it makes funny noises turn it down. I have run a 150 watt B-15T (15") cab in little rooms with an SVT head and have done so for years with no problems. How do you know if you are running full power at any instant? Output power is instantaneous with a source like a bass guitar, it's only constant with a constant tone like from a signal generator, if you are an exceptionally even player you might be at a fairly constant output most of the time, but more likely your amp could put out anywhere from 0 watts and up and then hit a good loud low E and it's cranked. If you are not playing it's putting out 0 watts, play a loud low B or E and it could be at maximum rated power.
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Right. I've never blown or creased a speaker because I know what a stressed cab sounds like. But if you run a cab with the volume pegged and the gain real high, you can easily kill an 800-watt cab with an 800-watt head.
 
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#74
The mechanical power handling of an 800 watt "RMS" rated speaker may only be 400 watts at 40-50Hz, this is why large amps used without good common sense and self control can end poorly for the speaker.
 
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#75
agedhorse said:
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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Good to know. I had no idea. However, mine is running cooler using it bridged into my 410 than it did with the 410/115 stack I used to use (hooked one up in each channel - both were 8 ohm cabs). I commonly ran that at 10 to 10:30. So perhaps I'm running a little above or below 1/3. Thanks for the info agedhorse, I never would have guessed that. Always appreciate you insights.
 
#77
DavC said:
please protect your ears ..!! from someone who lost 95% hearing in my left ear while in highschool ! (1974)
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Amen to that. I toured with a nightclub group back in the early 70's playing 5-nights a week, 50 weeks a year for 3-years and luckily only have moderate hearing loss. However that "moderate" loss means I have trouble understanding speech if background noise gets to be too much and I run the volume on the TV much higher than my wife likes so I don't have to keep asking her "what'd they say?" My hearing above the high mids drops off drastically. Running the volume up lets me hear it again, but about blows everyone else out of the room. Definitely NOT a good situation

So, I bit the bullet and hearing aids for both ears should arrive in the next week. I've been cautioned to be sure to remove them for rehearsals...
 
#78
Just adding the 2nd cab to the same amp should get you in the neighborhood of +6db, which is like quadrupling your amp power. You get about +3 from the more or less doubling the wattage from running at half the impedance, and another +3 from doubling the speaker area (not exactly but close enough, since nobody knows what a "db" sounds like anyway). So 750-800w range is completely fine, and I would say anything in the range of 500-1200 or so would be well within the usable range. Beyond that is probably overkill. You could always get a Trace AH-1200-12, which would probably slay with those cabs (and you could run stereo effects if you were into that).
 
#79
An SVT is 300W and capable of killing small furry animals at 100 paces, anything more powerful will only create a tear in the fabric of space-time and generate a super massive black hole.
 
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#80
I have never blown a speaker and don't know what a stressed speaker sounds like. Also I don't understand why anyone would play a cab at anywhere close to it's limit.

You don't drive your car at 70mph in 2nd gear, you do that safely and without causing damage by getting into top first. If it's going to get loud add cabs. Headroom in amps seems to be a concept that most players understand. I ensure that I also have headroom in my cabs. I also think I get a better tone by doing this.
 
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