Using a head that has a higher wattage than the cab

Discussion in 'Amps [BG]' started by bass_thefish, Jan 12, 2013.


  1. bass_thefish

    bass_thefish

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    I have a vintage hiwatt 2x15 that has the original fane speakers in it. The cab is only rated for 100w at 8 ohms.

    I was just wondering if it would be bad if I used say a 400w head. I don't want to blow the speakers out of my cab but I would like more power than the 100w head I'm using. The guitar player in my band seems to think it should be fine but I'm hesitant to trust him since I've had some bad experiences already with some speakers through my pa system.

    Any info on the subject is appreciated!
     
  2. CL400Peavey

    CL400Peavey Supporting Member

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    This is why you have a volume knob. If the cab sounds like you are pushing it too hard, then you are.
     
  3. Bass_Pounder

    Bass_Pounder

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    Won't get any louder, but will be more likely to blow the cab if you are not very careful in your volume knob useage.
     
  4. valencia0919

    valencia0919 Supporting Member

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    The power ratings on cabs are ignorable, I would say. You really need to hear it out yourself. If you go pass certain level of gain, it might start farting, which is not good for your cab. There should be a plenty of threads about this problem. Use search function!
     
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  6. BassmanPaul

    BassmanPaul Gold Supporting Member

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    Using a 400W amp with a cabinet rated at 100W is a recipe for disaster. You will inevitably blow the drivers.
     
  7. Thomas Kievit

    Thomas Kievit Thou shall not F*** up the groove Supporting Member

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    I was thinking the same. The best for him would be a different amp that can handle a higher wattage.
     
  8. Bassman62

    Bassman62

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    Who would dream of expecting an ancient speaker to live up to todays requirements, speakers of today are totaly different to those we used in days gone by.
     
  9. rockman1

    rockman1

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    i have a vintage acoustic 301 folded horn cab that i bought in the 70s.it had a 300w cerwin-vega 18 40hm in it.i just recently blew it up buy running a acoustic 600w head through it that puts out 450w at 4ohms.very stupid.i replaced it with a carvin 500w 4ohm speaker that is working very well.
     
  10. Bassman62

    Bassman62

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    The Accoustic folded horn cab was from the 1970s with a speaker that is ancient compared to todays technology.

    Modern loudspeaker are far more robust to those of the 70s where if you had a 100 watt amp you were always told you needed a 200 watt cab.
     
  11. bongomania

    bongomania Gold Supporting Member

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    The truth is a combination of the above posts. Those old speakers are simply not capable of handling more power, they will die. But OTOH if you turn the volume on the amp down to where there is no distortion (blatting, fuzzing) from the speakers, and if you play with consistent smooth dynamics (no big peaks from thumping the strings etc.) then you can use that amp with that cab all night long. Except, see the dilemma? You are using a head capable of putting out more wattage, but you can't use that wattage.
     
  12. bass_thefish

    bass_thefish

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    Thanks a lot for all the help! You've all pretty much confirmed my original beliefs.
    I guess I'll stick with my V4. It still sounds great I was just hoping to cut through the mix a bit better, but I guess that's what DI is for.
     
  13. KrisHayes

    KrisHayes

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    Exactly. Get a new cab! You don't wanna be in a gig situation reaching for the master!
     
  14. JimmyM

    JimmyM Supporting Member

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    If a cab has a 100w power handling limit, running more than a 100w head isn't going to do a thing for you.
     
  15. Bassmec

    Bassmec

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    Today they build in an enormous difference between X max and X damage/lim into the driver design and use much heavier voice coil assemblies, this has made it possible for those suffering from, here to fore unimagined levels of idiocy:hyper: to operate bass loudspeaker systems without returning it under warranty in week 1.
    This has been a major advance and although in terms of high frequency response, tone and efficiency things have taken a bit of a steep dive in pure performance terms since the formerly ubiquitous JBL K 140 and
    similar high performance drivers from the seventies, idiot proofing has advanced considerably, to the point at which even though the loudspeaker low frequency fart out point is still almost exactly the same, it is now at far less than half the thermal rated power.
    Meaning that the modern bass player can perform with a much greater frequency of farting noises emanating from his modern cabinet without any danger of this horrendous row suddenly succumbing to the melting point of copper, Stubbornly still resisting sales technology nomenclature advances at a lowly 1084 deg C.
    Another huge recent advance in bringing bass guitar amplification equipment into compass for the disabled or mentally impaired has been the use of neodymium lightweight magnet materials and very thin plywood.
    This has had the knock on effect that many modern loudspeaker cabinets are now almost as loud (in boomy boxy bass sound terms) when auditioned from the back the cabinet.:bag:
     
  16. avvie

    avvie

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    Good info Bassmec for the cab retarded such as myself. What year would you say was the turning point in this technology? And if I had a 4 ohm SWR Goliath Jr II cab from the early 90's would you recommend a speaker change?
     
  17. Bassman62

    Bassman62

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    The point is if it works there is the proof, I build my own cabs using Eminence Neos to a compact design built from 12mm ply with bracing struts on all internal walls, I don't need to augment through F.O.H on all but the largest gigs.
    The overall build cost to me is around £100 GBP including castors (I don't have to pay for a nameplate).
    Gone are the days when a huge W folded horn cab was needed to pump out the sound.
    More to the point and slightly digressing is how compact sound systems at concerts are these days compared to 20+ years ago when you saw loads of various types of cabs stacked up to the roof either side of the stage for the disabled or mentally impaired sound engineers and crew.
     
  18. chienmort

    chienmort

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    one thing that has been hinted at is that those old Fanes Celestions, JBLs etc had a much better midrange than current 15s and I suspect that they were also more efficient. The race to ultra, high power, high xmax speakers has been at the expense of mid range/efficiency. So if you replace with modern 15s you may well be disappointed with the sound.
     
  19. chienmort

    chienmort

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    Where do you get Eminence neos and build a cab for £100s
     
  20. Bassmec

    Bassmec

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    Back in the day we would drive 15" JBL 4560 cabs with 150 watts of the old Amcron DC 300' IE half a channel and we did the same with 16ohm 2" horn units and 16 ohm 1" horns above that.
    At Tasco sound and light we used eventide digital delay to time align the rig and Midas consoles to mix with.
    Knebworth main stage for the big lips tour had thirty DC 300's a side.
    It was loud clean and very punchy and the sound didn't tend to blow away in the wind quite as much as the arrays we have today, as we had a speaker on axis with just about everybody in the audience it only lost out at the windward end of the stage a bit.
    Yes the old stuff was better for windy outdoors where there is no substitute for cubic inches.
    And the new array is very much better for indoor closed environments where notch filtering and pulling phase nodes about with digital system controllers is handy.
    Now without all the horn loading of the old school system, the
    industry standard amp has gone from the Amcron DC 300A at 500watts per channel to about the same number of MA5000VZ's. at 2500 watts a channel.
    The thing is that with all that plywood around one fifteen a whole 40 footer full of 4560's only weighed 6 tons and that's not an efficient load when the vehicle is OK for 19 tons.
    So after the seventies Things just started getting smaller and heavier and now they are getting even smaller and much much lighter but the power supply cables are getting immensely heavy.:bassist:
    Of course the old school efficiency is making a comeback with lightweight materials and so we are moving steadily back to the seventies designs for outdoor gigs.
    [​IMG]
    Takes me right back to the old Martin systems, the midrange phase plugs are kind of cool diversion from the old Phillishave style mids.:bassist:
     
  21. Bassman62

    Bassman62

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    Where did the shot come from, a museum? BTW where are the 4560s? don't see any 4520a either.
     

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