100 watts/50 watts~ only 3% difference in volume?

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cellardweller said:
There is a potentially informative thread going on over here ->100 watts is only 3% louder than 50 watts....

Just curious if anyone 'round these parts might beg to differ with what's been said there....

What say yee? :)
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While it is mathematically correct, dB wise, with tube amps for guitar it's not so simple. Amps are rated with no clipping, but the volume they can put out when they squeeze against the rails can vary quite a bit. For example, I have a 44 watt Fender Super and a 50 watt Marshall, and going strictly by the numbers they should be indistinguishable, volume-wise. When they are both BTTW, however, the Marshall is quite a bit louder.
 
What is interesting to me is the fact that most (possibly all) of the amps they mention have essentially two volume knobs. One for pre and one for post. To me, that radically changes your perception of volume because you rarely have the post cranked all the way up to full. Most all of the amps I own have ONE knob for volume (i.e. my bassman, 100watt super lead, pro junior, and nano). I also find it hard to compare various amps because they all have different tones.

I can compare the bassman and super lead because they are essentially similar amps. 2 independent channels with single volume knobs per channel. In volume, the marshall is louder, but really not by much. The bassman breaks up very quickly whereas the marshall stays "clean" longer. I don't know... I think this is a somewhat moot conversation because how many people can really bring a 50 or 100 watt amp to a gig and play it at full potential? Why do people need to be so goddamn loud! ;) I usually gig nowadays with my bassman (into a hotplate) to a 4x12 bridged with a blues junior. Its really probably too loud for most places.
 
ggunn said:
While it is mathematically correct, dB wise, with tube amps for guitar it's not so simple. Amps are rated with no clipping, but the volume they can put out when they squeeze against the rails can vary quite a bit. For example, I have a 44 watt Fender Super and a 50 watt Marshall, and going strictly by the numbers they should be indistinguishable, volume-wise. When they are both BTTW, however, the Marshall is quite a bit louder.
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That would then be because the speakers are probably not the same. The efficiency of a speaker is more important than wattage. (unless its absurd...ex: 100 vs 1)

cellardweller said:
There is a potentially informative thread going on over here ->100 watts is only 3% louder than 50 watts....

Just curious if anyone 'round these parts might beg to differ with what's been said there....

What say yee?
Click to expand...

Yes, there is not much difference volume wise from 50 - 100 watts and 99 out of 100 people wouldn't be able to tell you the difference. There is a SLIGHT bit of headroom gained, but even that I wouldn't brag about because its so minor.

from the linked thread said:
Supposedly Marshall and most British made amp companies only rate there amps at average wattage and they can as much as double when cranked.
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I don't know that they rate them different, I believe it is true with all tube amps. Marshall does not recommend you use a 100 watt amp with their 100 watt 1960AX (Greenbacks) because the amp can peak at over 150 watts (I read 150-180 on technical page somewhere) when cranked.
 
Outlaws said:
That would then be because the speakers are probably not the same. The efficiency of a speaker is more important than wattage. (unless its absurd...ex: 100 vs 1)
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Point granted, though I don't know if that totally accounts for the diff. I could try both amps through the same speakers, I guess, but the Super is configged for a 2 ohm load. As I said, with guitar amps it's not that simple; I do know for a fact that my 50 watt Marshall is considerably louder than my 44 watt Super. Why that is isn't the point; it's that just looking at the wattage doesn't tell the whole story.
 
apl said:
All else being equal it takes about ten times the power to sound twice as loud. This is because your ear is logarithmic.
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I thought that this was measured in SPLs, not with subjective hearing.
 
ggunn said:
Point granted, though I don't know if that totally accounts for the diff. I could try both amps through the same speakers, I guess, but the Super is configged for a 2 ohm load. As I said, with guitar amps it's not that simple; I do know for a fact that my 50 watt Marshall is considerably louder than my 44 watt Super. Why that is isn't the point; it's that just looking at the wattage doesn't tell the whole story.
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The SuperReverb isn't configured for 2 ohms, I used to have one. It can accept a 2 ohm load. I believe the current 410 configure is series/parallel @ 4 or 8 ohms. There is an extension speaker jack so you can run a seperate cab with the internal speakers, that is why the rating is so low.

But take a look at the efficiency of the speakers. The websites for the companies all have them. Only a single dB or two is enough to make an amp a lot louder. Plus, if your 50 watt Marshall is a single 12 or a 212, that would be another big factor. The 410 will move more air than either of those.
 
timthetortoise said:
I thought that this was measured in SPLs, not with subjective hearing.
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SPL (Sound Pressure Level) is usually expressed in dB refrenced to 20 µPa and twice as loud is 3 dB more (or 6 dB if you've got the terms squared). It takes twice as much power to get twice as loud, but it doesn't sound twice as loud. It's barely perceivably louder.
 
Outlaws said:
The SuperReverb isn't configured for 2 ohms, I used to have one. It can accept a 2 ohm load. I believe the current 410 configure is series/parallel @ 4 or 8 ohms. There is an extension speaker jack so you can run a seperate cab with the internal speakers, that is why the rating is so low.

But take a look at the efficiency of the speakers. The websites for the companies all have them. Only a single dB or two is enough to make an amp a lot louder. Plus, if your 50 watt Marshall is a single 12 or a 212, that would be another big factor. The 410 will move more air than either of those.
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My Super is a '68 with 4 10's all in parallel, and a label on the speaker out jack says "2 ohms". I don't know what yours was, but
http://www.ampwares.com/ffg/super_reverb_sf.html shows the amp I have, and if you look about halfway through the specs you'll see the line:
Speakers/Load: 4 x 10"/2 ohms (8 ohms each in parallel). It's been on the bench and its output was measured at 44 watts.

My Marshall is an '81 JMP head with two 6550's over a 4 12 cab (Celestion greenbacks) and blows the Super, volume-wise, out of the room. I've not measured its output.

But we're arguing over trivialities here. Whether it's speaker efficiency, power delivery over and above the non-clipping rated power, or a combination of both, simply looking at amp power ratings and calculating dB ratios does not tell the whole story of which amp is louder (or not) and by how much.
 
a proven fact. if one 50W produces 120db, two 50watts side by side will produce 120 plus 3 = 123db

it's always 3db. IF you double the noisemaker, meaning; put two 50w amps side by side, and you get a 3db raise in noise.
BUT!! a 100w amp is louder than two 50watters.
 
Jouni said:
a proven fact. if one 50W produces 120db, two 50watts side by side will produce 120 plus 3 = 123db
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As long as you are talking about two identical amps into identical speakers, then yes.

BUT!! a 100w amp is louder than two 50watters.
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I don't know about that one.
 
Jouni said:
a proven fact. if one 50W produces 120db, two 50watts side by side will produce 120 plus 3 = 123db

it's always 3db. IF you double the "noisemaker", meaning; put two 50w amps side by side, and you get a 3db raise in noise.
BUT!! a 100w amp is louder than two 50watters.
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This seemingly contradicts the premise originally put forth in the thread over at the boogie board.... :confused:
 
ggunn said:
My Super is a '68 with 4 10's all in parallel, and a label on the speaker out jack says "2 ohms". I don't know what yours was, but
http://www.ampwares.com/ffg/super_reverb_sf.html shows the amp I have, and if you look about halfway through the specs you'll see the line:
Speakers/Load: 4 x 10"/2 ohms (8 ohms each in parallel). It's been on the bench and its output was measured at 44 watts.

My Marshall is an '81 JMP head with two 6550's over a 4 12 cab (Celestion greenbacks) and blows the Super, volume-wise, out of the room. I've not measured its output.

But we're arguing over trivialities here. Whether it's speaker efficiency, power delivery over and above the non-clipping rated power, or a combination of both, simply looking at amp power ratings and calculating dB ratios does not tell the whole story of which amp is louder (or not) and by how much.
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I had a Marshall 412 1960AX loaded with Greenbacks. They are extremely efficient.
http://professional.celestion.com/guitar/products/classic/spec.asp?ID=6

Infact, they are a full 3dB more efficient than the Jensen speakers I had in my Super Reverb.

:D ;)
 
RE: Super Reverb

I was unaware the old Supers were all parallel. The 2 ohm on the output is just informing of the lowest load that can be used. All the reissue Supers now say "minimum 2 ohm". But if yours are all parallel then I won't aregue with that. But you can safely unplug your internal speakers and hook it to the 412 if you want to see how loud it gets.
 
Outlaws said:
I was unaware the old Supers were all parallel. The 2 ohm on the output is just informing of the lowest load that can be used. All the reissues now say "minimum ___ load". But if yours are all parallel then I won't aregue with that. But you can safely unplug your internal hook it to the 412 if you want to experiement.
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Well, of course I realize that; it's just that it's still not an apples to apples comparison with the Marshall since the Super's output tranny is for a 2 ohm load and my Marshall head is set for 16 ohms - my 1960 is a 16 ohm cab (4 16 ohm Celestion greenbacks in series/parallel). Which all speaks to my point that it's not as simple as cacultaing dB ratios based on rated watts.
 
You can't compare a marshall with a fender and get any meaningful results. A 50 watt marshall will be louder than a 50 watt fender, the wattage has nothing to do with it. There are too many variables when you aren't using the same amps to compare.

If you took a 50 watt JCM800 loaded with EL34's and a 100 watt JCM800 loaded with EL34's, set all the controls on '10', the 100 watt head would be 3db louder.

Comparing different amps is useless.
 
ggunn said:
My Super is a '68 with 4 10's all in parallel, and a label on the speaker out jack says "2 ohms". I don't know what yours was, but
http://www.ampwares.com/ffg/super_reverb_sf.html shows the amp I have, and if you look about halfway through the specs you'll see the line:
Speakers/Load: 4 x 10"/2 ohms (8 ohms each in parallel). It's been on the bench and its output was measured at 44 watts.

My Marshall is an '81 JMP head with two 6550's over a 4 12 cab (Celestion greenbacks) and blows the Super, volume-wise, out of the room. I've not measured its output.

But we're arguing over trivialities here. Whether it's speaker efficiency, power delivery over and above the non-clipping rated power, or a combination of both, simply looking at amp power ratings and calculating dB ratios does not tell the whole story of which amp is louder (or not) and by how much.
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]

I will check mine after next practice, I have the same amp. It may not be as loud as a 50 watt marshall but it sounds so much better. :p
 
Interesting...Are the wattages stated RMS? I would like to know the true meaning of root means squared. I've "heard" that RMS ratings can be quite deceiving and confusing.
 
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