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300w amp = ???

Discussion in 'Amps and Cabs [BG]' started by RoMeRz, Mar 10, 2006.


  1. RoMeRz

    RoMeRz

    Feb 13, 2006
    Glasgow, Scotland
    Ive got a 300w head, but thats at 4ohmz. If I get an 8ohmz cab - what would the wattage end up being ?
     
  2. TrooperFarva

    TrooperFarva

    Nov 25, 2004
    New City, NY
    It depends, what kind of amp is it?
     
  3. When an amp puts out 300W into impedance X, at impedance 2(X) it usually does around 180. Thus, your 300W@4ohms amp will probably do 180W@8ohms.

    HTH, YMMV, HAND, YMIABFS, etc.
     
  4. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    If it is a modern solid state head, then "something a bit above 150 W" is likely, and give or take 10 W doesn't matter. My GK Backline 600 head is rated at 180 W into 8 Ohms.

    You start with half of the 4-Ohm power, and then add a bit for the reduced voltage drop through the power supply from running at lower output current.
     
  5. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    You would get the same if its a tube head.
     
  6. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    But tube Ohms are louder than solid state Ohms ;)
     
  7. 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
    I don't know whether to kill myself or go bowling.
     
  8. RoMeRz

    RoMeRz

    Feb 13, 2006
    Glasgow, Scotland
    So if i were to use two 8ohmz cabs they could still both pump about about 150w each ?
     
  9. Just to clarify Most tube amps put out the same power @ 2-4 or 8 ohms. You just use different taps off the transformer. ANd there is no such thing as a difference in tube vs solid state ohms. The difference is in precieved power output between tube and solid state amps of the samw power RMS rateing. Tubes supposedly being much louder
     
  10. What are you talking about, tube ohms all the way, at 2 or 4 my SVT sounds ace :rolleyes:




    ;)
     
  11. RoMeRz

    RoMeRz

    Feb 13, 2006
    Glasgow, Scotland
    Well I have the opertunity to get a decent 4x10 200w cab. If i were to get this and then maybe something else along the same lines later on - would they work together ?

    Im restricted to a small budget so atm I can't buy anything. Just wondering if these would work.

    My amp is a Solid State Laney RB9.
     
  12. Groundloop

    Groundloop

    Jun 21, 2005
    Toronto
    If the 4x10 is a 4 Ohm cab, then you wouldn't be able to add another cab later, since your amp is rated for a minimum 4 Ohm impedence. If the 4x10 is 8 Ohms, then you could add another 8 Ohm cab later.
     
  13. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    That's a false dichotomy. :bag:
     
  14. chaosMK

    chaosMK

    May 26, 2005
    Albuquerque, NM
    Hi-fi into an old tube amp
    I use 4 tube ohms, and it sounds awesome.
     
  15. Herman

    Herman

    Dec 25, 2005
    Lynchburg, VA
    Er...what's a "tube ohm"?
     
  16. cadduc

    cadduc

    Mar 4, 2006
    Ohms is Ohms
    Volts is Volts
    and
    Watts is Watts
    and
    Ohms law is universal

    and the deal is this
    the only reason a ss amp of 300 w rms @ 4 Ohms
    is not as loud as a tube amp of 300 w rms @ 4 Ohms
    is because the manufacturer lied about the the output

    or because it is sick and needs to be fixed
     
  17. No, because a 300 watt SS amp will not handle running a 300 watt output of anything bar a constant waveform, seeing playing a bass is not a constant smooth waveform, ie it has many jumps, those jumps in signal clip the SS amp, and you get a horrible sound, so people turn down lower so thier amp isnt putting out 300 watts

    With 300 watts of tube amp, the clipping occurs, but it sounds good, so people are fine with it!
     
  18. Herman

    Herman

    Dec 25, 2005
    Lynchburg, VA
    OK, so what's a "tube ohm"? Or did they mean say "tube watt" which is what your response addresses?
     
  19. ghindman

    ghindman

    Feb 10, 2006
    No such thing as a tube watt, or a tube ohm, he's either yanking your chain, or very confused - likely the former. As mohawk said, the SS/Tube power difference is largely perception. You can't drive a SS head past the point of signal distortion, or you get very harsh, unpleasant clipping, while driving a tube head past the point of distortion is pretty much normal operating procedure. So, you generally get 'more power'/volume from a tube head than a SS head with the same power rating. (plus mfg power ratings are somewhat subjective)
     
  20. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Ah, thanks for the vote of confidence. I was indeed chain-yanking.

    You think we have our arguments about Watts. A friend of mine talks about "British Watts" or "American Watts" with respect to guitar amps.