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Head and Power amp?

Discussion in 'Amps and Cabs [BG]' started by Dream Works, Jun 5, 2005.

  1. Dream Works

    Dream Works

    Dec 5, 2003
    I own a Peavey Mark III 300 watt amp, which powers a Madison 1x15 cab. Whenever I'm playing with my drumming brother, I often have to crank up the volume rather high in which the clip LED lights. Even When I play in my band (The guitarist has one of them small little combo amps) I feel as if I should have to crank it up that much to be able to cut through. Now I'm wondering, is it possible to run my Mark III into a power amp and boost the volume? I've done much searching on this, but to no avail. I've checked the output of the head, and the output gives 23 volts RMS. If attach that to a power amp, would that work or would we have to call the fire department? I'm also wondering -- Does a power amp simply cause the signal to become whatever wattage it gives or would it boost the signal (If I have a 500w power amp, would it take any signal it gets and churn it out into 500w, or would it amplify 500w)?
  2. Sending 500 watts into a power amp = fire and death. Do not do that. You can run the line out on your amp into a power amp, and then use the power amp to power another speaker cabinet. Note that this will also require the purchase of more speakers.
  3. fire bad, FIRE BAD

    Yeah, as was said, if you have a preamp output or a balanced output (XLR) you can use them to power a power amp
  4. I think there's a chance you are not getting the full 300watts out of your amp. If your cab is 8 ohms you are only getting about 150-200watts out of it. If your cab is 4 ohms then disregard this post.

    May I suggest that if you get another 8 ohm 1x15 cab you would get a 6db increase due to increased power and cone area. It would take about a 1000watt amp to accomplish the same thing.
  5. surely you mean a 3db increase?

    because each cab will still only be getting 150 watts, so it will double the loudness (maybe just a bit over if its a tad over 150 watts at 8ohms)
  6. You get a 3db increase when you double the wattage AND when you double the cone area.

    If you fed the same signal into 1 or 2 cabs there would be a 3db increase with 2 cabs.

    If you double the signal into 1 cab there would be a 3db increase.

    When you double the signal AND double the cone area there would be a 6db increase.

    Anyway back to the original post! ;) ;) ;)
  7. Hmm, ok, maybe ive got this wrong

    Double wattage into same cab = 3db increase

    but this is doubling the wattage, so each cab is getting the same amount of wattage as the single, each cab would not be getting 300 watts, so it would surely be a 3db increase?

    Anyway, im probably wrong, yeah, back on topic . . .
  8. Tash


    Feb 13, 2005
    Bel Air Maryland
    Assuming the current cab is 8ohms he is not getting 300 watts out of the head right now. He's getting ~150.

    Adding a second cab will double the cone area AND increase the output to ~300 watts @4ohms. You can think of it as 150 watts into each of two speakers, but functionally its the same thing: the amp is now putting out 300 watts where before it was only putting out 150.

    300 = 2*150

    So the net result would be a doubling of BOTH speaker area AND power output.
  9. fairly nough, my bad, physics was never my strong point :)
  10. Dream Works

    Dream Works

    Dec 5, 2003
    Isn't there another way to boost my volume without having to buy a cab >.>? A volume pedal?
    Oh and yes, my head puts out 150w into 8 omhs.
  11. Fraid not, a volume pedal cuts not boosts, to control the volume (im sure)

    Because if you increase the input signal the amp is going to clip at either the pre or power stage, and that'll induce (the equivilant) of DC current and fry your speaker and quite possibly the amp aswell
  12. Buying another cab is the most cost effective and sensible way to get more volume in your particular situation.

  13. Dream Works

    Dream Works

    Dec 5, 2003
    Luckily, my birthday is coming up in a few months (It took me half a year for me to actually get my rig last year ~_~) and I have a little stash for such occasions.
    It seems that I'm lacking quite some info on my cab. Eh.
    Madison 153 1x15" speaker + Horn
    500 watts RMS, 1000 watts peak.
    8 Ohms.
  14. karrot-x

    karrot-x Inactive

    Feb 21, 2004
    Omicron Persei 8
    I suggest you get a Avatar 2x10 to complement your Madison 1x15. It's pretty cheap too ~$220 shipped.
  15. Get another cab. I had same prob. Got myself a 4x10 cab & kaboom!!! If you are in U.K. find a good qual. either 4x10 2x10 or 1x15 cab maker. I actually measured the Fender 2x10 in my local recently & built one up (I had a couple of ok 10" spkrs) - it sounds great! BUT wait until I get the same Eminence spkrs that are in the Fender cab & put 'em in mine!

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