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High wattage amps into low wattage cabs

Discussion in 'Amps and Cabs [BG]' started by mancefine, Feb 10, 2014.

  1. mancefine


    Jul 7, 2013
    Endorsing Artist: Orange Amplifiers and Spector Basses
    Hi Guys,

    As usual, I'm sure this has been covered a bunch on TB, but I couldn't find it immediately.

    I have an Orange TB1000 and the OBC 4x10 and OBC 115 stack. Both cabs are 8 ohms and the 4x10 is rated at 600 watts while the 115 is at 400. I usually run both cabs with the head at 4 ohms. Obviously there are times that I don’t want to carry both cabs to jam, so here is my question: Since I can run the head at 4 or 8 ohms, what risks do I run if I run the TB into the OBC 115? That is running a 900 watt class D head (I think the head is 900 watts at 8 ohms and 1000 at 4) into a 400 watt cabinet. To be more specific, I am wondering if the head is always putting out 1000 watts no matter where the volume/gain are set, or If it puts more wattage out as you crank the volume? Can I use the head with the 115 cabinet if I barely crank the volume, or will plugging the head into the cabinet in general result in overdriving the cabinet and possibly blowing it? Is there any negative effect on my head by doing this, or would the risk just be posed to the cabinet? Thanks!
  2. KablesP


    Oct 29, 2013

    Chances are you won't blow the speaker unless you have the head cranked. Chances are you won't have to crank a 1000 watt head. Also, smaller gigs are generally quieter so you don't blow peoples heads off with volume.

    I don't see a problem as long as you don't push the cab too hard.
  3. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    As long as you are sensitive to the sound of an over stressed loudspeaker and don't drive it into farting and you are not hiding its stress with distortion effects or octivider etc.
    Not a problem just be careful.:bassist:
  4. JHAz


    Jun 29, 2011
    greater power equals greater volume, right? so when there's less volume, it's less power. The amp puts out however much power is called for by the level of the input and the setting of volume and gain controls. essentially zero when you are not playing, and when you play at home, likely not much more than one watt, depending on cab efficiency.

    You CANNOT judge power by the volume control setting. But if you don't use a highly distorted tone, the speakers will tell you when they're starting to be overdriven, (they fart out) and you can turn down a bit. Simply using your ears and a bit of common sense can make the combination perfectly safe. IMO. YMMV, etc.
  5. IMO, this is no different than a high powered engine in a light weight vehicle.

    Go back in time to 1970, when the air was dirty and sex was clean.
    Dodge put a few 426 Hemi engines into small E-body vehicles like the Challenger.
    This combination by itself was not fatal to the vehicle.

    When operated by a dumb@ss, most of these wound up wrapped around trees.
    It all depends on the operator.

    I routinely power my small cabs with a PLX-3002, but not at full power.
  6. el murdoque

    el murdoque

    Mar 10, 2013
    I have not seen the numbers for the 1000, but the TB 500 is known to put out a lot more than 500W in certain circumstances.
    Given, you have a full stack, you will not bring only one cab to a place where you need a lot of volume, so you shall be fine.

    Don't dime it.
    When the cab starts farting, dial back on the master or the bass knob.
    The only possibility for you to kill the cab is to ignore the signs.
    Turn the amp way down and listen to it. now turn it just a bit louder. sounds the same only louder. now repeat, and again. still, sounding the same, only louder.
    Somewhere when you're past 10 o clock on the master, the cab might start adding distortion and farting noises. That's when its about to take serious damage.
    It's hard to ignore.
    Usually that's only possible because you have to crank the amp to be able to hear yourself.
  7. Sid Fang

    Sid Fang Reformed Fusion Player Supporting Member

    Jun 12, 2008
    You're probably in more danger of cooking your 115 running in parallel with the 410 than using it alone. At least when it's used alone, and you drive it into the danger zone, you'll probably hear it breaking up and farting before real damage is done. With the more robust 410 running cover for it, you might not, even though you have to run the rig as a whole rig harder to get to the danger zone.
  8. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

    Feb 24, 2013

    There are two kinds of limits - thermal, which has to do with how fast/well the voice coil can reject the heat it makes as a result of working to pump air - and mechanical, which has to do with how much excursion is available.

    Applying too much power to a cab can put it against its mechanical limits immediately. While this is bad, it also sounds bad - so listen for it.

    Thermal limits are harder to judge, but are rarely encountered immediately. If you find the cab sounding quieter at the end of a session, you may be there. "Thermal compression" is what you're searching for through the FAQ's...

    The volume knob is like a lamp dimmer - at low volumes you are sending little power. For a variety of reasons, the knob position has very little relationship to delivered power, however - it is _not_ linear. So you can't go in thinking "I'm safe because I'm only on '2'"

    Total gain plays a picture, as does EQ. Boosting bass in an effort to make a cab sound louder than it can is a sure way to hit mechanical limits in a hurry.

    You must listen and act accordingly...
  9. mrmills


    Jun 22, 2009
    Kent, UK
    I use an Ashdown Little Giant (the orange one) into two speaker cabs that are not designed to take the 500W per cab the amp can provide, they are both around 300W cabs. I have not blown the speakers up yet.

    I agree with everyone else who has commented that you just need to be careful. Driving a speaker too hard (with too much power) will not only sound awful but will cause damage through overheating the voice coil. I know it sounds obvious but a more powerful amp can drive a lot more current into the same speaker. The problem is, you might not be able to hear sound problems during transients where large currents would be driven into the speaker(s) for a short time.

    I could not say what is safe as it does really depend on what you are playing, for how long and how well the speakers are ventilated.
  10. BassmanPaul

    BassmanPaul Gold Supporting Member

    Aug 25, 2007
    Toronto Ontario Canada
    +1 If you must use this poor combination stack the 15 in the top position you you have a chance of hearing its cries of pain. Do a search on the subject - it's been covered extensively.
  11. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Everyone else has covered most things pretty well. If you insist on having a 4x10 + 1x15 setup, please at least put the 1x15 on top so you can hear it when it cries out in pain. Most likely, the 4x10 is louder and goes deeper than the 1x15, so with the 1x15 on bottom, you won't hear it when it is stressed.
  12. mancefine


    Jul 7, 2013
    Endorsing Artist: Orange Amplifiers and Spector Basses
    I literally never turn my volume above 4 (out of 10) when running both cabs, so I think I should be OK as far as blowing the 15.

    I can understand hating on the 410/115 set up if it were Ampeg, as I used to hate it, but the Orange set up is night and day different. It sounds amazing, period.
  13. KablesP


    Oct 29, 2013
    Try one of these speakers.

    It can handle 600 watts and isn't too expensive for what you get. Not sure how it sounds compared to the Orange speaker but you could flip the Orange speaker to make this one a little cheaper. Its also 8ohms so you can still run the 410.
  14. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    It's not "hating" on the setup. It also doesn't matter if you're on 4, 1, 1.78, 3.14 or 11 on the volume knob. That knob has little bearing on how much power you're pushing out. You could easily be pushing the 1x15 past it's mechanical or thermal limits, and having it stacked on the bottom, you likely will never hear it until it is far too late.

    TB doesn't just pick things out to recommend and have as "best practice" willy nilly, to make players lives difficult. It's done to potentially save you money, time, and headache. What's the harm in reversing your stack? If it sounds good to you, that's fine and dandy. The "issue", is as I have said above. The 4x10 is louder, and likely goes deeper than the 1x15 anyway, so having a 1x15 "because it goes lower" is a misnomer at best.
  15. wcriley


    Apr 5, 2010
    Western PA
    As has been said: Knob position means nothing.
    Almost every knob and switch on an amp is (to some degree) a "volume control".
  16. AaronVonRock


    Feb 22, 2013
    I have an Orange TB 500 powering two Hartke 112 Hydrives (300 watts each). Sometimes I only use one cab and have the same concerns as you. When using one cab, I keep the bass knob turned way down and have the volume knob around 9-10 o'clock. So far, so good. No issues. But it's always in the back of my mind that something could happen.