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A Question about Watts and Ohms

Discussion in 'Amps [BG]' started by ilansgroove, Feb 19, 2014.


  1. ilansgroove

    ilansgroove

    Joined:
    Jan 24, 2012
    Location:
    paris, france
    i searched many threads and couldn't find my answer so i'll just ask .... :)

    i'm using a Tone Hammer 350

    i use a Trace Eliot 8Ohm cab , so i know my amp delivers only 175W

    I'm looking for either a second cab under 8 Ohm or replace it to a 4 Ohm cab

    my question is, if i get a 4 ohm amp that can deliver more than 350 Watts, will it damage the amp?

    how about a second cab, does it matter if the 2 cabs make together more than 350 Watts .... as long as i don't go lower than 4Ohm?
     
  2. orangejulius3

    orangejulius3

    Joined:
    May 6, 2013
    Location:
    La Habra CA
  3. HolmeBass

    HolmeBass Supporting Member

    Joined:
    Jan 18, 2007
    Media:
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    Location:
    Charlottesville, VA
    Uh... not sure if there is a language barrier at work here, or just some real bad understanding.

    Cabinets don't "make" watts. Amps do.

    Your ToneHammer amp has a minimum load of 4 Ohms. That means the load can't be below 4 Ohms, or the amp would produce too much power, too much heat, and burn itself up.

    So if you add a 2nd cabinet to your existing 8 Ohm one it should be another 8 ohm cabinet. The two 8 ohm cabinets, connected in "parallel", will give a 4 ohm load. Read up on Wikipedia or Google about "parallel" vs "serial" circuits.

    99% of speaker connections on amp heads, and on the back of the cabinets, are parallel connections, so whether you run both cabinets into the amp, or "daisy-chain" by running the amp to one cab, and then connect that cab to the 2nd cab, it will all still be parallel connections.

    The wattage rating on the cabinets is their "maximum wattage" determined by heat considerations in the speakers. Having cabinets that can handle more power than your amp will deliver is fine, won't hurt either. Having cabinets that take significantly less power than your amp delivers could end up hurting the cabinets.

    With two cabinets of the same nominal impedance - that is, ohm rating - connected in parallel they each take 1/2 of the total power put out by the amp.

    Your question about a "4 ohm amp than can deliver more than 350 watts, will it damage the amp?" is undecipherable, not sure which word should be "cabinet" although obviously one of those "amps" should be "cab" instead... please repost after considering my answer and reading the amps FAQ.
     
  4. Cirk

    Cirk

    Joined:
    Jan 16, 2011
    Location:
    Newport News, VA
    If language is a barrier, I'm sure one of our French speaking friends will be glad to help.
     
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  6. ilansgroove

    ilansgroove

    Joined:
    Jan 24, 2012
    Location:
    paris, france
    hehehehe

    i guess i kinda blabbered too much
    but it's ok, i understand , just wanted to reassure myself ....

    don't go lower than 4ohm ...
    for example , if the Cab is a 550 Watts 4 ohm ... and i use my TH 350 ... it will be able to deliver its max output of 350 Watts, the cab will be ok since it can accept up to 550 Watts ...
     
  7. ilansgroove

    ilansgroove

    Joined:
    Jan 24, 2012
    Location:
    paris, france
    i would actually prefer a hebrew speaker :)
     
  8. bassmeknik

    bassmeknik

    Joined:
    Nov 6, 2009
    Location:
    Fair Haven, MI
    please read the sticky notes at the top of the amps forum. It would answer this and much more.

    Amps make watts, cabs don't. You are concerned that your 8 ohm cab won't be loud enough because you can't get all the watts your amp has to deliver while running at 8 ohms? Your amp will provide more power if given (connected to) a 4 ohm cab compared to an 8 ohm cab. It is the total impedance the cab or combination of cabs that determines the wattage a given amp will be able to produce. So yes your amp will provide more watts if you have it connected to a 4 ohm load compared to an 8 ohm load. HOWEVER this does not account for speaker sensitivity so I really think you should ask youself what you are trying to accomplish here. Many 8 ohm cabs have high sensitivity and would be louder than other 4 ohm cabs hooked up to the same amp.

    I will assume for a minute that your existing rig is not loud enough and that is why you are asking (?) You could get another trace cab like you have (most recommended, most flexible rig...), or just get another cab that is more sensitive (higher db/1 watt @ 1 meter spec). The impedance isn't your problem the cab sensitivity is the issue. A 4 ohm load will allow your amp to produce more power but that doesn't necessarily translate into louder. (a second identical cab would however due to more speaker area). Not all cabs are created equal so learn a bit about the science of loud and spend your money on either a:

    1. second identical cab (or)
    2. different cab with higher sensitivity rating (ohms are not as important as sensitivity, just don't go below the 4 ohm minimum)

    Having more power at the amp than the cabs can handle is ideal for clean headroom but must be run with a knowledgeable eye on the controls so the amp doesn't damage the speakers. If on the other hand you are not familiar with equipment then having speakers that can handle more than the amp can deliver lessens the chance of failure from operator error. UNDER POWERING SPEAKERS WILL NOT HURT THEM.
     
  9. gumtown

    gumtown Supporting Member

    Joined:
    May 7, 2007
    Location:
    New Zealand
    With regard to either getting another 8 ohm cab or replacing the 8 ohm one with a 4 ohm,
    you are better off having as much speaker surface area as possible (more speakers).

    i.e.
    (i don't know the specs on your particular cab)
    but for example....
    if your existing cab is a 2 x 10 @ 8 ohm,
    and adding an extra 2 x10 @ 8 ohm
    (total = 4 x10 @ 4 ohm)

    will give you better use of your power than a single 2 x 10 @ 4ohm.

    Then you can choose to use a single cab for small venues, or both cabs for bigger venues.

    That is my opinion, others may have different views.
     
  10. bassmeknik

    bassmeknik

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    Nov 6, 2009
    Location:
    Fair Haven, MI

    correct
     
  11. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Location:
    New Zealand
    Adding another of your Trace cabs is a much better bet. More speakers trumps more watts as a rule.
     
  12. Cirk

    Cirk

    Joined:
    Jan 16, 2011
    Location:
    Newport News, VA
    If a Hebrew speaker is required, i can just call my friend Matt. No problem.
     
  13. ilansgroove

    ilansgroove

    Joined:
    Jan 24, 2012
    Location:
    paris, france
    ok !!!

    thanks ...

    a second Cab it is :)

    now a slightly different questions

    if i use the trace eliot 400W 8ohm and GK 100W 8ohm.. i will damage the GK, right?
     
  14. orangejulius3

    orangejulius3

    Joined:
    May 6, 2013
    Location:
    La Habra CA
    Hebrew speakers?
    We're they at NAMM this year?
    Do you know the specs on those speakers?
     
  15. ilansgroove

    ilansgroove

    Joined:
    Jan 24, 2012
    Location:
    paris, france
    i think i'll manage in english ...

    anyway if we start to exchange messages in hebrew it would be rude to the rest of the guys here :)
     
  16. gumtown

    gumtown Supporting Member

    Joined:
    May 7, 2007
    Location:
    New Zealand
    Yes - something matched would be better, or atleast something equivalent.
    the 100 watter will consume 1/2 of the 350 watts from the amp, and crap itself.
     
  17. ilansgroove

    ilansgroove

    Joined:
    Jan 24, 2012
    Location:
    paris, france
    hebrew speakers are usually very loud !!! heheheheheehe
     
  18. ilansgroove

    ilansgroove

    Joined:
    Jan 24, 2012
    Location:
    paris, france
    ok, that's what i thought ....

    thanks
     
  19. bassmeknik

    bassmeknik

    Joined:
    Nov 6, 2009
    Location:
    Fair Haven, MI
    Just an fyi, the idea of mixing cabs is debated highly here on TB. It is generally accepted that mixing different types of cabs gives mixed results. Some pairings work well together some do not, One camp on TB (I am one...) believe the best set up is a rig of all the same type of speakers (drivers) with one exception, multi driver rigs that use crossovers to send selected frequencies to woofers, mid drivers and (if equipt) tweeters (such as the fEarful designs).

    Others like to pair 15's for lows with 10's for the highs or similar but send a full range signal to both. Some like this arrangement, with all due respect to my fellow TBers I don't.

    This is why you will get some that say get another identical Trace cab where others might say get a 115 to go with that 210 etc... If you like 15's get a 215 for more volume or 2-8 ohm 115's so you get a 4 ohm load when using both cabs.

    So IMO you need either a second identical cab or a different cab altogether with higher sensitivity.
     
  20. orangejulius3

    orangejulius3

    Joined:
    May 6, 2013
    Location:
    La Habra CA
    You could use it if ever needed but it's not recommended.

    I would use the GK cab by itself and set your amps settings to go easy on that cab. Once set up, attach your trace cab but do not move your settings.
    You will gain volume with more speakers and a little more power from your amp. I would adjust volume down if needed. Plus the GK cab would be better on top so you can here if it's in distress.
    i.e. Distorting, farting out.
     
  21. JohnMCA72

    JohnMCA72

    Joined:
    Feb 4, 2009
    No guarantees. No matter what the watt ratings of either amp or speaker, or where you might set the "volume" or "gain" knobs, it's still possible to generate a signal that's hotter than either the amp or speaker can handle.
     

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