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View Full Version : SPEAKER WATTS vs AMP HEAD WATTS



piebaldpython
July 18th, 2009, 08:11 AM
This is probably a DUH question but I just want to make sure. Should the Watts a speaker(s) is rate at always be larger than the amp head watts that are driving it???

So, if you have an amp head of 30 Watts and it's driving a 15 Watt speaker, you're definitely running the risk of "cooking it", right????

And it doesn't matter if the amp head is tube, hybrid or SS, right?

WackyT
July 18th, 2009, 08:15 AM
Yup. Speaker watt rating should be larger than amp watt rating.

ibanezjunkie
July 18th, 2009, 08:22 AM
my cab is 140 watts, and i use 100w and a 5 watt head.

im cautious about getting anything bigger than 100w because i like ot have a good 40w of space before i kill my speakers.

thats why the valve junior cab is 75 watts isnt it?

tunghaichuan
July 18th, 2009, 09:09 AM
The general rule of thumb I like to use is at least double the speaker wattage for any particular amp. So if I'm using a 25W amp, I like to have it connected to at least a 50W speaker load. With a tube amp, the 25W rating is usually measured with the amp fairly clean with low harmonic distortion. When the amp is cranked, the wattage rating will go up the louder it will get. The classic example of this is the 100W Marshall head. It puts out 100W relatively clean. When dimed it can put out 150W or so. In that case it is necessary to have it hooked up to a 200W cab or better.

However, there are players who use 100W Marshall heads with 100W rated Marshall cabinets (4X12" Greenbacks) and have done so for decades with no problems. I personally wouldn't do it, but it seems to work for some.

It is okay to connect a high-wattage speaker to a low wattage amp. Like Junkie pointed out, the VJ cab is rated at 70W but the VJ head is only puts out 5W clean.

tung

jim p
July 18th, 2009, 11:47 AM
One place to look regarding speaker wattage rating relative to the power of the amp is the Q&A section over on the Ted Weber speaker web site. http://www.webervst.com/sptalk.html
Reading through all the questions and answers will give you a better understanding of speakers and information to base your choice on. One thing to keep in mind the higher the wattage the larger the voice coil so the speaker is more dampened and the efficiency will be lower. Another interesting thing about speakers more for bass then guitar is the wattage rating can be a function of the speaker cabinet it is mounted into. A small closed back cabinet will dampen the speaker movement allowing for higher wattage while an open back or ported cabinet will lower the wattage rating.
You could also e-mail Weber speakers to see what there answer is to find out even if you are considering a different brand of speaker.

Just noticed this article and thought I would add it to see if anyone has tried this Directivity Modifier on a speaker cabinet http://www.tgpwebzine.com/?page_id=424. It sounds interesting and might reduce the boxey sound on a small combo amp. What is nice is they show output signal response at different angles to show that it does work. Just take a hit in high frequency peaking so will need to turn up the treble.
Then on the wrong wattage speaker front maybe this could be the result http://www.sacbee.com/breaking/story/1471436.html

Duff49
July 28th, 2009, 03:25 AM
I replace a lot of speakers and always make sure that there is a significant difference between the amp output and the speaker rating. I put a celestion seventy eighty in a ss Crate Flexwave fifteen reverb. Big tonal improvement. The Celestion is a lot more powerful than the amp.

I plug my Blackheart three/five watt head into my Epiphone twelve inch cab which I'm not sure what it i rated at and I plug my Blackheart and my Epi Valve Junior v.3 into my Epiphone super heavy Eminence loaded Southern California four by twelve cabinet rated at some awesome rating compared to the five watt output of the Blackheart and Valve Junior - and both amps sound super great thru that big cabinet; all BS aside, they sound incredible and I don't think I'm hurting the cabinet by doing so.

Those little five watt amps might be peaking out at twenty five watts or so. That Crate fifteen watt flexwave might be peaking out at fourty five watts or so.

I'd say be careful and get lots of wattage if you plan on cranking up your amp, adding boost pedals or other pedals that boost the signal, overdrive, etc. This is just amateur tech experience talking, but I would adhere to good solid advice from people who know before buying speakers. I asked around before I did but just can't remember the exact details. Memory problems and I'm only 59.

Another super important factor to consider when re speakering an amp is SENSITIVITY of the speaker. Some speakers are 95dB, others are up to 103dB. The higher the dB rating the louder the speaker will be and just a couple dB will make the speaker WAY louder. I like to get over 100dB, preferably 102 or 103. This really gets the amp to scream. My Ragin Cajun' in my Super Champ XD, which I'm playing myself to sleep with, hooked up to a Boss Overdrive OD-3 has a lot more sensitivity than the low dB stock Fender speaker which looked like a miniture model compared to the huge Ragin Cajun' which had a massive magnet about twenty times the size of the stock Fender speaker, and overall superior construction. Those Eminence speakers are a real value. My Celestion seventy eighty is no slouch either and I got it free, brand new. I seem to find deals by just checking around.

You going to re speaker that Behringer GM110 Pie? I thought of doing that to mine. The Eminince Ragin Cajun' is a good speaker for modelling amps, if it has the correct ohm rating and they are only like 64 dollars from MF. Very hot very nice sounding speaker, as attested by many.

Good luck,

Duffy