Choosing correct speaker wattage...

Discussion in 'Amps and Cabs' started by Lammy, Jan 25, 2006.

  1. Lammy

    Lammy Member

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    I have a traynor yba-1 and just got a hiwatt dr504, I was planning on getting an avatar oversized 2x12 cab with a red fang/wizard, maybe a pair of red fangs. I know both of these amps are rated at 50 watts, but are pretty loud, should i be more conservative on the speaker side of things and get more wattage? i.e. a weber bluedog/silver bell @50w a piece?
     
  2. GCDEF

    GCDEF Supporting Member

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    I'd shoot for a combined wattage of at least 60. Avatar should be able to point you in the right direction.
     
  3. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    The bad news is that power ratings for tube amps are all over the map, but are higher when the amp is dimed/pushed/buried (whatever word works for you!)...I recently perused the JCM 800 manual that is available online... get this...

    1) A 1987 style Marshall is rated at 50 watts, with dual EL 34 tubes, right? Well, in the Marshall manual it states (and I quote this directly):

    Power Output: Typical power at clipping, measured at 1KHz, average distortion 3%, in excess of 50 watts RMS into 4.8 or 16 ohms. Typical output power at 10% distortion 90 watts into 16 ohms.

    2) My Risson ETA 100 with dual 6550 tubes is rated at 60 watts. Now I wonder if that means it actually puts out 100.

    3) Found the page on 2203 & 4103 amps with four EL 34 tubes in the same JCM 800 manual. Supposedly the power output of those amps is 115 watts RMS at 4% distortion into 4/8/16 ohms, but 170 watts at 10% distortion into 4 ohms.

    Needless to say, the 10% factor must be somewhere near the "dimed" region, right?

    You'd better carefully review what your amp puts out for wattage, and more importantly, what does it put out where you set it, so that you can get the right power handling for your speakers.

    No wonder they put two of those "100" logo 4x12's with those old Marshall 100 watt Plexis, they knew what they put out, and knew the "safe zone" of power handling for their speakers.

    Myself, I always try to setup speakers to handle the amp with a comfort zone. So an amp that puts out 20 watts dimed, gets at least 25 watts, preferably a 30 watt speaker. I feel the best tone is achieved when speakers are between 50-85% of their power rating. Those Plexis putting out 170 watts at full clip had either 200 (8 G12M 25 watters) or 240 watts (8 G12H30 30 watters) watts power handling. Enough to handle a Plexi on 10 with some headroom to spare.

    Seems to make sense...so if I were you, carefully review your wattage needs, but you need to know what your amp is putting out first. Good luck!
     
  4. Lammy

    Lammy Member

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    So how does the wattage rating compare with speakers that don't have the same number i.e. the wizard 75 watts, and the red fang which is 30 watts? Do i have to worry about blowing the red fang but not the wizard?
     
  5. Lucky7

    Lucky7 Senior Member

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    Here is another question.....A tech once told me if I paired a high wattage speaker with a low watt amp it would sound thin. For example....at that time I had a Ghia head running through a 1-12 cab loaded with a Tonker. I was told this was a terrible match and I wasn't getting near the tone I should be. Well.....to me it sounded great. Plenty of low punch and certainly not thin by any means. Did I just misunderstand or is it best to say match an amp like the Ghia with a Greenback?
     
  6. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    It depends on the speaker, IME. I know my H75 65 watt speakers sound great with a 25-30 watt amp. So much of this depends on the amp/amp settings and how it makes the speaker respond that it's going to be subjective, and personal preference plays a part, too.

    For example: Marshall Studio 15's came with a V30, a 60 watt speaker for a 15 watt amp.

    Lots of folks like to run their speakers on the "ragged edge" of their power handling, because the speaker adds in more of it's own tone/cone character when "pushed hard"...although you can run the risk of blowing the speaker, too. Witness the power ratings I posted above for the JCM 800 Marshalls, for example. They put out "well past" their rated outputs...even the Studio 15 puts out 29.5 watts RMS at full clip. I wouldn't use a 25 watt G12M type speaker with that amp, even a 30 watt might be on the "ragged edge" if the amp is totally healthy.

    I'm having my Studio 15 completely restored, new Mercury Magnetics power tranny (mine was a replacement and putting out 15% less plate voltage than it was supposed to!), and Mercury is also doing the output transformer by unwinding and rebuilding a new (better) one.

    Should be a fun grab and go combo when it's all done, but I'll be using an H75-8 30 watter in the combo...so I'll know whether or not it's real healthy if it blows my speaker...huh? LOL I'll report back when it's done...
     
  7. tjs

    tjs Senior Member

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    Sorry to hijack the thread, but is a G12H30 (reissue) safe to use in a 1X12 combo with 4xEL84? I generally run the amp in half-power mode, so I would think it should be safe under those conditions, but would running it in full-power mode be a bad idea?
     
  8. tjs

    tjs Senior Member

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    On second thought, after reading Scumbag's post, even the half-power mode might be dangerous to my speaker? If so, what would be a good replacement for the G12H30 at a higher power rating that has a similar tone (but preferably without the piercing treble when I crank the amp)?
     
  9. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    tjs...1/2 power mode...probably OK...full power mode...probably smell funny quickly!

    Most quad EL 84 amps I know put out at least 30-35 watts clean, and a bunch more when "pushed", dimed, etc... proceed cautiously... what amp are you talking about? Maybe the amp maker can tell you it's real "full clip" RMS output (kinda like that Marshall JCM 800 manual I quoted) at your "sweet spot" on the volume knob...I'd ask them as they should know best.
     
  10. tjs

    tjs Senior Member

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    Yeah, I had a feeling that would be the case. It's a Kingsley D32, and it's one of the louder 4XEL84 amps I've owned.

    Which of your speakers would you recommend for a similar balanced tone, but at a safe output rating? The amp has a Vox/Fender-like clean tone, but drives more like a Marshall/Dumble hybrid, so I'd like something that connects well with all of those tone types.
     
  11. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    The H75-XHP (X for your preferred ohm rating)... probably out to take this to email so as not to further hijack this thread...OK?
     
  12. Guinness Lad

    Guinness Lad Silver Supporting Member

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    I think another point which is very important is are the speakers going into a OB or CB cabinet and if you play clean stuff or heavy distortion. OB cabs will not dampen the speaker properly which can lead to excessive cone movement i.e. speaker rub through hard driving. I have heard from various sources that OB cabs should use speaker that are at least 50% above the amp's output rating. For example 50 watt amp uses 75 watt speakers minimum. I'm pretty sure CB cabs without ports and such could go a little lower but I'd still be a little cautious.
     

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