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Overloading an Amp?

Discussion in 'Amps [BG]' started by accidentprone13, Dec 14, 2012.

  1. accidentprone13

    accidentprone13

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    I play bass in a drum/bass sludge metal duo, and I use a lot of pedals, but especially a lot of overdrive, reverb and pitch shifter. I'm using a Hartke HA2500 head with one 4x10 right now (I know it's not good for sludge, but I'm making the best with what I have right now) and the overdrive makes the bass sound like it is just way too much for the head. I posted about this a while back thinking I had blown a speaker, but now I know it's definitely just overloading the head.

    The HA2500 runs at 175 watts with only one 4x10 plugged in, if I added a second cabinet it would run at 250 watts at 4 ohms. Would that be enough power to handle a really gritty overdrive? Or am I just out of luck until I can find the money to get a new rig?

    :help:
  2. Downunderwonder

    Downunderwonder

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    Adding another cab is well proven to get you more bass for little extra money.

    When you say you're sure you're overloading the head I presume when you unplug all your pedals the amp plays clean ok?

    That would mean you're overdriving the amp with all your pedals. When this happens your signal clips in a non musical way. Or your overdrive pedal could be making unpleasant noise.

    The other way to "overload" it is putting too many cabs on it and overheating it.

    "Really gritty overdrive" is independent of the volume and number of cabs. The volume with the amount of low end you want mostly determines how well the rig does it. If you chop out some low end and have no tweeter to worry about the one cab will go stupid loud until it eventually melts the coils. It wouldn't surprise me if you did that already but you you say you haven't so I guess it's a tough one.
  3. JimmyM

    JimmyM Supporting Member

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    I think you will be fine, but consider that a 175w SS head can put out over twice that in peaks (350w peak) and your cab likely takes around 400w before fartout would start. So it's possible to blow it, but you should be able to get some crank going before that point. But as always, remember the golden rule for cabs...if it sounds like it's going to explode, it probably will.
  4. accidentprone13

    accidentprone13

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    Solid advice there at the end! haha.

    The clean signal is fine, just checked it yesterday. I really don't think anything is blown or melted, but how would I tell if the coils were melted?
  5. Downunderwonder

    Downunderwonder

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    The obvious clue is they stop working.

    If you notice it gets quieter back off!

    If you've stopped playing and they don't make nasty sounds you probably got away with it.

    The 9v battery test will show if one stopped working altogether. You can gently push the cones in to feel for scraping on suspicious ones.
  6. will33

    will33

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    Probably just have some pedals set too loud. Adjust them so the sound with the pedal on is the same volume as the clean sound with it off. Use them to change the tone and not blast a lot more volume.
  7. will33

    will33

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    If the cab has a tweeter, turn it down or off or disconnect it. May've blown the tweeter with all the distortion.
  8. Mr. Foxen

    Mr. Foxen

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    Cut some lows after all the effects, like on the amp, or with an eq at the end of the chain. Probably all sorts of lumpy boost going on there that is upsetting things.
  9. ThisBass

    ThisBass

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    Most of the time this assumption is of theoretical nature.

    Feeding the amp with "overdrive" signals permanent all along the time I'd point out that the output power of amp cant be higher then 1/3 to 1/2 of the rated power. But if the output power is gained/mastered to higher RMS values probably the cooling system runs eventually into protecting mode due of to much heating losses.


    Whereas some random clipping content of signals at "full power" is unsuitable to overload the cooling system of any amps.
  10. Downunderwonder

    Downunderwonder

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    Ugh. Any time he stops to let something ring on the next note can fart out if he slams it. That's 350w or thereabouts in theory speaking out.
  11. accidentprone13

    accidentprone13

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    There's good advice all through this thread. Gonna try backing off the pedals and seeing what that does. I'm also getting a second 4x10 while I'm hope, so hopefully that helps.

    However, I am really worried about messing up the cooling system. I don't want to melt the insides and have no idea how to check that haha. Also how I would I go about disconnecting the tweeter?

    Thanks everyone, you've all been a huge help.
  12. JimmyM

    JimmyM Supporting Member

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    Second cab will help a ton. Insides of the head should be OK as long as you don't run it flat out all the way up.
  13. accidentprone13

    accidentprone13

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    Awesome, it's only been on about 7 or 8. Thanks!
  14. ThisBass

    ThisBass

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    I told the physics but not the myths.
  15. Downunderwonder

    Downunderwonder

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    No myths here.
  16. ThisBass

    ThisBass

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    That's the myth
  17. Downunderwonder

    Downunderwonder

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    I got that from the same source as Jimmy, Bill Fitzmaurice. You gonna tell us clipping kills woofers next?
  18. ThisBass

    ThisBass

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    That's misunderstanding theoretical nature, or physics.
    But never ever anybody did the prove.
    Audible clipping kills your sound but not the woofers.
    But non audible clipping kills your sound as well, depending on your choice/fashion of listening.
  19. JimmyM

    JimmyM Supporting Member

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    Sure seems to be backed up by a lot of amp builders throughout history.
  20. Downunderwonder

    Downunderwonder

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    Sorry mate, I know English isn't your first language, but you never seem to really make a point.

    At issue is whether or not a solid state amp will roughly double its power output, 1.4x its rail voltage briefly under a sudden spike of input. I'm told they do, you say they don't.

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