Discussion in 'Amps and Cabs [BG]' started by mosmute, Apr 22, 2002.

  1. mosmute


    Apr 22, 2002
    i really don't know much about amps and stuff but i have a 10x4 cab with a wattage of 500 and an impedance of 8ohms. and i also have another cab-1X15 and impedance of 8ohms.
    If i plan on using both, does that mean i need an amp head with a power output of 4 ohms and a wattage of under or equalto 300?
    i was looking at buying a GK 800rb or a swr 350 and i was wondering if everything would be kosher.

    thanx for the help
  2. you need a head with a minimum output of 4 ohms or less. The closer to 4ohms you get, the more power and headroom you'll get, just make sure the head is not rated at 8 ohms, and you should be fine.

    The maximum power you should use is the combined power handling of the cabinets, 500watts plus the 15's power rating. You can go over it without doing damage, but be careful.
  3. SWR 350 specs:


    GK 800rb specs:

    These pages show that both of these amps are stable to at least 4 ohms which is what you would need if you have parallel outputs and two 8 ohm cabs. Most heads will be ok with 4 ohms, but some full tube heads that I've seen are only stable down to 8 ohms.

    As for the power, you don't need to stay below a certain amount. You should be fine with either of the two heads you have chosen. In fact, some people argue that more power is better, no matter what speakers you have, because you'll get less distortion from the head itself.

    This is the way I understand it, but I'm by no means an expert.. If I'm wrong someone please correct me!!

    Hope I helped:)
  4. steve-o

    steve-o Guest

    Apr 17, 2002
    i have been told by funkcarnivore that
    not enough power hurts the speaker more than to much power.
    you don't run that full 500 watts that is what head room is for not to run the full wattage
    so get something with as much power as possible and just not turn it up. it will also sound a lot cleaner just my 2 cents

  5. go to carvin's website and to the Dr. Sound articles. Select the one about ohms, watts, and impedence. It's a really informative article; it saved my cabinet.
  6. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    how much low end do you get out of those 10 fours?
  7. mosmute


    Apr 22, 2002
    so let me get this straight.

    i should get a head that is closer to 800W (300+500) as to not under power my cabs.
    and closer to 4Ohms???????

    or am i still really confused????
  8. Matthias


    May 30, 2000
    Vienna, Austria
    If you want to use the full potential of your cabs you should get a head rated 800W or more at 4Ohms (or 2x400W at 8Ohms if it is a stereo amp).
    Of cause you can also use a head with less power, this will not hurt your cabs unless you don't push the amp too far beyond it's limit (if you do this, the amp will start clipping and this can damage your cabs).

  9. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    There's no such thing as underpowering your cabs. That's a myth. The only time a smaller amp is a problem is when it's not enough for your gig, and you have to crank it and make it clip. That's being underpowered *for your gig*, not for your cab. As Matthias pointed out, if a smaller amp, say, 300 watts, lets you play as loud as you need to, with enough volume in reserve, then it's not a problem.

    If you're not sure how much power you need, though, consider that it's better to have more power and not need it than to need it and not have it. I'd get a bigger amp if I were you and could afford it.
  10. mosmute


    Apr 22, 2002
    can you recomend something???
  11. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Much depends on the budget, of course, but for reasonable bucks I'd consider the Carvin R1000, my fave bang-for-the-buck head and a very good amp, period, IMO. The G-K you mentioned could work, and some folks swear by the Peavey Firebass 700 (one heavy piece of gear, though). I'm not an Ampeg person at all, but somebody here could probably give you the straight dope on those. If an Eden is in your price range, the WT-800 would probably be great. SWR often strikes me these days as a tad pricey for what you get, but if you get a good deal on the 350, you like the sound, and it's enough power for you, go for it. If you come acroos a used SWR 750 (I think that's the model? the bigger version of the 350) in good shape, think about that too.
  12. ZuluFunk

    ZuluFunk Supporting Member

    Apr 14, 2001
    I recommend you get a stereo power amp. Then you can turn down the side that can only handle 300watts without having to keep the 410 down. You'll never get a perfect balance, but you can save your cabs. You also can run the load bridged by daisey chaining them to the mono signal. A

    Just about any power amp gives you this ability. Call the Carvin Pro Audio 800 number on the Carvin site. QSC and Mackie service reps can also explain it.

    My advice would be a stereo power amp with about 800-1000 watts per side at 8 ohms, or a bridged mono 4ohm load at 1200-1600 watts. Remember, that's just available power. Just like your car, you don't have to red-line the thing. Having headroom saves your cabs, amp, and tone.

    When I first came to TB, I had no clue, and I had been playing for over 20 years. I still don't know squat, but I am able to talk the lingo when making a purchase. One thing I did learn is to try to have about double the watts that each cab can handle at a normal signal in each side to keep from clipping and screwing things up big time. I aslo learned that power amps are an economic option.